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[ Upstream commit 457965c13f0837a289c9164b842d0860133f6274 ]
If trigger_data_alloc() fails and returns NULL, event_hist_trigger_parse()
jumps to the out_free error path. While kfree() safely handles a NULL
pointer, trigger_data_free() does not. This causes a NULL pointer
dereference in trigger_data_free() when evaluating
data->cmd_ops->set_filter.
Fix the problem by adding a NULL pointer check to trigger_data_free().
The problem was found by an experimental code review agent based on
gemini-3.1-pro while reviewing backports into v6.18.y.
Cc: Miaoqian Lin <linmq006@gmail.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Link: https://patch.msgid.link/20260305193339.2810953-1-linux@roeck-us.net
Fixes: 0550069cc25f ("tracing: Properly process error handling in event_hist_trigger_parse()")
Assisted-by: Gemini:gemini-3.1-pro
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit e39bb9e02b68942f8e9359d2a3efe7d37ae6be0e upstream.
When a process forks, the child process copies the parent's VMAs but the
user_mapped reference count is not incremented. As a result, when both the
parent and child processes exit, tracing_buffers_mmap_close() is called
twice. On the second call, user_mapped is already 0, causing the function to
return -ENODEV and triggering a WARN_ON.
Normally, this isn't an issue as the memory is mapped with VM_DONTCOPY set.
But this is only a hint, and the application can call
madvise(MADVISE_DOFORK) which resets the VM_DONTCOPY flag. When the
application does that, it can trigger this issue on fork.
Fix it by incrementing the user_mapped reference count without re-mapping
the pages in the VMA's open callback.
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Vincent Donnefort <vdonnefort@google.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Link: https://patch.msgid.link/20260227025842.1085206-1-wangqing7171@gmail.com
Fixes: cf9f0f7c4c5bb ("tracing: Allow user-space mapping of the ring-buffer")
Reported-by: syzbot+3b5dd2030fe08afdf65d@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=3b5dd2030fe08afdf65d
Tested-by: syzbot+3b5dd2030fe08afdf65d@syzkaller.appspotmail.com
Signed-off-by: Qing Wang <wangqing7171@gmail.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 9678e53179aa7e907360f5b5b275769008a69b80 ]
The event_hist_poll() function attempts to verify whether an event file is
being removed, but this check may not occur or could be unnecessarily
delayed. This happens because hist_poll_wakeup() is currently invoked only
from event_hist_trigger() when a hist command is triggered. If the event
file is being removed, no associated hist command will be triggered and a
waiter will be woken up only after an unrelated hist command is triggered.
Fix the issue by adding a call to hist_poll_wakeup() in
remove_event_file_dir() after setting the EVENT_FILE_FL_FREED flag. This
ensures that a task polling on a hist file is woken up and receives
EPOLLERR.
Cc: stable@vger.kernel.org
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Tom Zanussi <zanussi@kernel.org>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Link: https://patch.msgid.link/20260219162737.314231-3-petr.pavlu@suse.com
Fixes: 1bd13edbbed6 ("tracing/hist: Add poll(POLLIN) support on hist file")
Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit f0a0da1f907e8488826d91c465f7967a56a95aca ]
The event_hist_open() and event_hist_poll() functions currently retrieve
a trace_event_file pointer from a file struct by invoking
event_file_data(), which simply returns file->f_inode->i_private. The
functions then check if the pointer is NULL to determine whether the event
is still valid. This approach is flawed because i_private is assigned when
an eventfs inode is allocated and remains set throughout its lifetime.
Instead, the code should call event_file_file(), which checks for
EVENT_FILE_FL_FREED. Using the incorrect access function may result in the
code potentially opening a hist file for an event that is being removed or
becoming stuck while polling on this file.
Correct the access method to event_file_file() in both functions.
Cc: stable@vger.kernel.org
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Tom Zanussi <zanussi@kernel.org>
Link: https://patch.msgid.link/20260219162737.314231-2-petr.pavlu@suse.com
Fixes: 1bd13edbbed6 ("tracing/hist: Add poll(POLLIN) support on hist file")
Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit f4ff9f646a4d373f9e895c2f0073305da288bc0a ]
The function graph tracer was modified to us the ftrace_ops of the
function tracer. This simplified the code as well as allowed more features
of the function graph tracer.
Not all architectures were converted over as it required the
implementation of HAVE_DYNAMIC_FTRACE_WITH_ARGS to implement. For those
architectures, it still did it the old way where the function graph tracer
handle was called by the function tracer trampoline. The handler then had
to check the hash to see if the registered handlers wanted to be called by
that function or not.
In order to speed up the function graph tracer that used ftrace_ops, if
only one callback was registered with function graph, it would call its
function directly via a static call.
Now, if the architecture does not support the use of using ftrace_ops and
still has the ftrace function trampoline calling the function graph
handler, then by doing a direct call it removes the check against the
handler's hash (list of functions it wants callbacks to), and it may call
that handler for functions that the handler did not request calls for.
On 32bit x86, which does not support the ftrace_ops use with function
graph tracer, it shows the issue:
~# trace-cmd start -p function -l schedule
~# trace-cmd show
# tracer: function_graph
#
# CPU DURATION FUNCTION CALLS
# | | | | | | |
2) * 11898.94 us | schedule();
3) # 1783.041 us | schedule();
1) | schedule() {
------------------------------------------
1) bash-8369 => kworker-7669
------------------------------------------
1) | schedule() {
------------------------------------------
1) kworker-7669 => bash-8369
------------------------------------------
1) + 97.004 us | }
1) | schedule() {
[..]
Now by starting the function tracer is another instance:
~# trace-cmd start -B foo -p function
This causes the function graph tracer to trace all functions (because the
function trace calls the function graph tracer for each on, and the
function graph trace is doing a direct call):
~# trace-cmd show
# tracer: function_graph
#
# CPU DURATION FUNCTION CALLS
# | | | | | | |
1) 1.669 us | } /* preempt_count_sub */
1) + 10.443 us | } /* _raw_spin_unlock_irqrestore */
1) | tick_program_event() {
1) | clockevents_program_event() {
1) 1.044 us | ktime_get();
1) 6.481 us | lapic_next_event();
1) + 10.114 us | }
1) + 11.790 us | }
1) ! 181.223 us | } /* hrtimer_interrupt */
1) ! 184.624 us | } /* __sysvec_apic_timer_interrupt */
1) | irq_exit_rcu() {
1) 0.678 us | preempt_count_sub();
When it should still only be tracing the schedule() function.
To fix this, add a macro FGRAPH_NO_DIRECT to be set to 0 when the
architecture does not support function graph use of ftrace_ops, and set to
1 otherwise. Then use this macro to know to allow function graph tracer to
call the handlers directly or not.
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Link: https://patch.msgid.link/20260218104244.5f14dade@gandalf.local.home
Fixes: cc60ee813b503 ("function_graph: Use static_call and branch to optimize entry function")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 912b0ee248c529a4f45d1e7f568dc1adddbf2a4a ]
Check the event length before adding it for accessing next index in
rb_read_data_buffer(). Since this function is used for validating
possibly broken ring buffers, the length of the event could be broken.
In that case, the new event (e + len) can point a wrong address.
To avoid invalid memory access at boot, check whether the length of
each event is in the possible range before using it.
Cc: stable@vger.kernel.org
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Fixes: 5f3b6e839f3c ("ring-buffer: Validate boot range memory events")
Link: https://patch.msgid.link/177123421541.142205.9414352170164678966.stgit@devnote2
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit f1547779402c4cd67755c33616b7203baa88420b ]
There is a pointer head_page in rb_meta_validate_events() which is not
initialized at the beginning of a function. This pointer can be dereferenced
if there is a failure during reader page validation. In this case the control
is passed to "invalid" label where the pointer is dereferenced in a loop.
To fix the issue initialize orig_head and head_page before calling
rb_validate_buffer.
Found by Linux Verification Center (linuxtesting.org) with SVACE.
Cc: stable@vger.kernel.org
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Link: https://patch.msgid.link/20260213100130.2013839-1-d.dulov@aladdin.ru
Closes: https://lore.kernel.org/r/202406130130.JtTGRf7W-lkp@intel.com/
Fixes: 5f3b6e839f3c ("ring-buffer: Validate boot range memory events")
Signed-off-by: Daniil Dulov <d.dulov@aladdin.ru>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 53b2fae90ff01fede6520ca744ed5e8e366497ba ]
When registering a second fgraph callback, direct path is disabled and
array loop is used instead. When ftrace_graph_active falls back to one,
we try to re-enable direct mode via ftrace_graph_enable_direct(true, ...).
But ftrace_graph_enable_direct() incorrectly disables the static key
rather than enabling it. This leaves fgraph_do_direct permanently off
after first multi-callback transition, so direct fast mode is never
restored.
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260213142932519cuWSpEXeS4-UnCvNXnK2P@zte.com.cn
Fixes: cc60ee813b503 ("function_graph: Use static_call and branch to optimize entry function")
Signed-off-by: Shengming Hu <hu.shengming@zte.com.cn>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 804c4a2209bcf6ed4c45386f033e4d0f7c5bfda5 ]
Commit 32dc0042528d ("tracing: Reset last-boot buffers when reading
out all cpu buffers") resets the last_boot_info when user read out
all data via trace_pipe* files. But it is not reset when user
resets the buffer from other files. (e.g. write `trace` file)
Reset it when the corresponding ring buffer is reset too.
Cc: stable@vger.kernel.org
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://patch.msgid.link/177071302364.2293046.17895165659153977720.stgit@mhiramat.tok.corp.google.com
Fixes: 32dc0042528d ("tracing: Reset last-boot buffers when reading out all cpu buffers")
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit f844282deed7481cf2f813933229261e27306551 ]
Since the per-cpu buffer_size_kb file is writable for changing
per-cpu ring buffer size, the file should have the write access
permission.
Cc: stable@vger.kernel.org
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://patch.msgid.link/177071301597.2293046.11683339475076917920.stgit@mhiramat.tok.corp.google.com
Fixes: 21ccc9cd7211 ("tracing: Disable "other" permission bits in the tracefs files")
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit f743435f988cb0cf1f521035aee857851b25e06d ]
The get_sample() function in the hwlat tracer assumes the caller holds
hwlat_data.lock, but this is not actually happening. The result is
unprotected data access to hwlat_data, and in per-cpu mode can result in
false sharing which may show up as false positive latency events.
The specific case of false sharing observed was primarily between
hwlat_data.sample_width and hwlat_data.count. These are separated by
just 8B and are therefore likely to share a cache line. When one thread
modifies count, the cache line is in a modified state so when other
threads read sample_width in the main latency detection loop, they fetch
the modified cache line. On some systems, the fetch itself may be slow
enough to count as a latency event, which could set up a self
reinforcing cycle of latency events as each event increments count which
then causes more latency events, continuing the cycle.
The other result of the unprotected data access is that hwlat_data.count
can end up with duplicate or missed values, which was observed on some
systems in testing.
Convert hwlat_data.count to atomic64_t so it can be safely modified
without locking, and prevent false sharing by pulling sample_width into
a local variable.
One system this was tested on was a dual socket server with 32 CPUs on
each numa node. With settings of 1us threshold, 1000us width, and
2000us window, this change reduced the number of latency events from
500 per second down to approximately 1 event per minute. Some machines
tested did not exhibit measurable latency from the false sharing.
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://patch.msgid.link/20260210074810.6328-1-clord@mykolab.com
Signed-off-by: Colin Lord <clord@mykolab.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 276f3b6daf6024ae2742afd161e7418a5584a660 ]
Mahe reported issue with bpf_override_return helper not working when
executed from kprobe.multi bpf program on arm.
The problem is that on arm we use alternate storage for pt_regs object
that is passed to bpf_prog_run and if any register is changed (which
is the case of bpf_override_return) it's not propagated back to actual
pt_regs object.
Fixing this by introducing and calling ftrace_partial_regs_update function
to propagate the values of changed registers (ip and stack).
Reported-by: Mahe Tardy <mahe.tardy@gmail.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/bpf/20260112121157.854473-1-jolsa@kernel.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 9df0e49c5b9b8d051529be9994e4f92f2d20be6f ]
The macros ENABLE_EVENT_STR and DISABLE_EVENT_STR were added to trace.h so
that more than one file can have access to them, but was never removed
from their original location. Remove the duplicates.
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Tom Zanussi <zanussi@kernel.org>
Link: https://patch.msgid.link/20260126130037.4ba201f9@gandalf.local.home
Fixes: d0bad49bb0a09 ("tracing: Add enable_hist/disable_hist triggers")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 0550069cc25f513ce1f109c88f7c1f01d63297db ]
Memory allocated with trigger_data_alloc() requires trigger_data_free()
for proper cleanup.
Replace kfree() with trigger_data_free() to fix this.
Found via static analysis and code review.
This isn't a real bug due to the current code basically being an open
coded version of trigger_data_free() without the synchronization. The
synchronization isn't needed as this is the error path of creation and
there's nothing to synchronize against yet. Replace the kfree() to be
consistent with the allocation.
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Tom Zanussi <zanussi@kernel.org>
Link: https://patch.msgid.link/20251211100058.2381268-1-linmq006@gmail.com
Fixes: e1f187d09e11 ("tracing: Have existing event_command.parse() implementations use helpers")
Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit e8a1e7eaa19d0b757b06a2f913e3eeb4b1c002c6 ]
__sprint_symbol() might access an invalid pointer when
kallsyms_lookup_buildid() returns a symbol found by
ftrace_mod_address_lookup().
The ftrace lookup function must set both @modname and @modbuildid the same
way as module_address_lookup().
Link: https://lkml.kernel.org/r/20251128135920.217303-7-pmladek@suse.com
Fixes: 9294523e3768 ("module: add printk formats to add module build ID to stacktraces")
Signed-off-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Aaron Tomlin <atomlin@atomlin.com>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkman <daniel@iogearbox.net>
Cc: Daniel Gomez <da.gomez@samsung.com>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Luis Chamberalin <mcgrof@kernel.org>
Cc: Marc Rutland <mark.rutland@arm.com>
Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Petr Pavlu <petr.pavlu@suse.com>
Cc: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 802eef5afb1865bc5536a5302c068ba2215a1f72 ]
After commit 37cce22dbd51 ("bpf: verifier: Refactor helper access type tracking"),
the verifier started relying on the access type flags in helper
function prototypes to perform memory access optimizations.
Currently, several helper functions utilizing ARG_PTR_TO_MEM lack the
corresponding MEM_RDONLY or MEM_WRITE flags. This omission causes the
verifier to incorrectly assume that the buffer contents are unchanged
across the helper call. Consequently, the verifier may optimize away
subsequent reads based on this wrong assumption, leading to correctness
issues.
For bpf_get_stack_proto_raw_tp, the original MEM_RDONLY was incorrect
since the helper writes to the buffer. Change it to ARG_PTR_TO_UNINIT_MEM
which correctly indicates write access to potentially uninitialized memory.
Similar issues were recently addressed for specific helpers in commit
ac44dcc788b9 ("bpf: Fix verifier assumptions of bpf_d_path's output buffer")
and commit 2eb7648558a7 ("bpf: Specify access type of bpf_sysctl_get_name args").
Fix these prototypes by adding the correct memory access flags.
Fixes: 37cce22dbd51 ("bpf: verifier: Refactor helper access type tracking")
Co-developed-by: Shuran Liu <electronlsr@gmail.com>
Signed-off-by: Shuran Liu <electronlsr@gmail.com>
Co-developed-by: Peili Gao <gplhust955@gmail.com>
Signed-off-by: Peili Gao <gplhust955@gmail.com>
Co-developed-by: Haoran Ni <haoran.ni.cs@gmail.com>
Signed-off-by: Haoran Ni <haoran.ni.cs@gmail.com>
Signed-off-by: Zesen Liu <ftyghome@gmail.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20260120-helper_proto-v3-1-27b0180b4e77@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 00f13e28a9c3acd40f0551cde7e9d2d1a41585bf ]
64-bit truncation to 32-bit can result in the sign of the truncated
value changing. The cmp_mod_entry is used in bsearch and so the
truncation could result in an invalid search order. This would only
happen were the addresses more than 2GB apart and so unlikely, but
let's fix the potentially broken compare anyway.
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://patch.msgid.link/20260108002625.333331-1-irogers@google.com
Signed-off-by: Ian Rogers <irogers@google.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 6435ffd6c7fcba330dfa91c58dc30aed2df3d0bf ]
When user resize all trace ring buffer through file 'buffer_size_kb',
then in ring_buffer_resize(), kernel allocates buffer pages for each
cpu in a loop.
If the kernel preemption model is PREEMPT_NONE and there are many cpus
and there are many buffer pages to be freed, it may not give up cpu
for a long time and finally cause a softlockup.
To avoid it, call cond_resched() after each cpu buffer free as Commit
f6bd2c92488c ("ring-buffer: Avoid softlockup in ring_buffer_resize()")
does.
Detailed call trace as follow:
rcu: INFO: rcu_sched self-detected stall on CPU
rcu: 24-....: (14837 ticks this GP) idle=521c/1/0x4000000000000000 softirq=230597/230597 fqs=5329
rcu: (t=15004 jiffies g=26003221 q=211022 ncpus=96)
CPU: 24 UID: 0 PID: 11253 Comm: bash Kdump: loaded Tainted: G EL 6.18.2+ #278 NONE
pc : arch_local_irq_restore+0x8/0x20
arch_local_irq_restore+0x8/0x20 (P)
free_frozen_page_commit+0x28c/0x3b0
__free_frozen_pages+0x1c0/0x678
___free_pages+0xc0/0xe0
free_pages+0x3c/0x50
ring_buffer_resize.part.0+0x6a8/0x880
ring_buffer_resize+0x3c/0x58
__tracing_resize_ring_buffer.part.0+0x34/0xd8
tracing_resize_ring_buffer+0x8c/0xd0
tracing_entries_write+0x74/0xd8
vfs_write+0xcc/0x288
ksys_write+0x74/0x118
__arm64_sys_write+0x24/0x38
Cc: <mathieu.desnoyers@efficios.com>
Link: https://patch.msgid.link/20251228065008.2396573-1-mawupeng1@huawei.com
Signed-off-by: Wupeng Ma <mawupeng1@huawei.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 033c55fe2e326bea022c3cc5178ecf3e0e459b82 ]
The fields of ftrace specific events (events used to save ftrace internal
events like function traces and trace_printk) are generated similarly to
how normal trace event fields are generated. That is, the fields are added
to a trace_events_fields array that saves the name, offset, size,
alignment and signness of the field. It is used to produce the output in
the format file in tracefs so that tooling knows how to parse the binary
data of the trace events.
The issue is that some of the ftrace event structures are packed. The
function graph exit event structures are one of them. The 64 bit calltime
and rettime fields end up 4 byte aligned, but the algorithm to show to
userspace shows them as 8 byte aligned.
The macros that create the ftrace events has one for embedded structure
fields. There's two macros for theses fields:
__field_desc() and __field_packed()
The difference of the latter macro is that it treats the field as packed.
Rename that field to __field_desc_packed() and create replace the
__field_packed() to be a normal field that is packed and have the calltime
and rettime use those.
This showed up on 32bit architectures for function graph time fields. It
had:
~# cat /sys/kernel/tracing/events/ftrace/funcgraph_exit/format
[..]
field:unsigned long func; offset:8; size:4; signed:0;
field:unsigned int depth; offset:12; size:4; signed:0;
field:unsigned int overrun; offset:16; size:4; signed:0;
field:unsigned long long calltime; offset:24; size:8; signed:0;
field:unsigned long long rettime; offset:32; size:8; signed:0;
Notice that overrun is at offset 16 with size 4, where in the structure
calltime is at offset 20 (16 + 4), but it shows the offset at 24. That's
because it used the alignment of unsigned long long when used as a
declaration and not as a member of a structure where it would be aligned
by word size (in this case 4).
By using the proper structure alignment, the format has it at the correct
offset:
~# cat /sys/kernel/tracing/events/ftrace/funcgraph_exit/format
[..]
field:unsigned long func; offset:8; size:4; signed:0;
field:unsigned int depth; offset:12; size:4; signed:0;
field:unsigned int overrun; offset:16; size:4; signed:0;
field:unsigned long long calltime; offset:20; size:8; signed:0;
field:unsigned long long rettime; offset:28; size:8; signed:0;
Cc: stable@vger.kernel.org
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reported-by: "jempty.liang" <imntjempty@163.com>
Link: https://patch.msgid.link/20260204113628.53faec78@gandalf.local.home
Fixes: 04ae87a52074e ("ftrace: Rework event_create_dir()")
Closes: https://lore.kernel.org/all/20260130015740.212343-1-imntjempty@163.com/
Closes: https://lore.kernel.org/all/20260202123342.2544795-1-imntjempty@163.com/
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
[ Different variable types and some renames ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 90f9f5d64cae4e72defd96a2a22760173cb3c9ec upstream.
When creating a synthetic event based on an existing synthetic event that
had a stacktrace field and the new synthetic event used that field a
kernel crash occurred:
~# cd /sys/kernel/tracing
~# echo 's:stack unsigned long stack[];' > dynamic_events
~# echo 'hist:keys=prev_pid:s0=common_stacktrace if prev_state & 3' >> events/sched/sched_switch/trigger
~# echo 'hist:keys=next_pid:s1=$s0:onmatch(sched.sched_switch).trace(stack,$s1)' >> events/sched/sched_switch/trigger
The above creates a synthetic event that takes a stacktrace when a task
schedules out in a non-running state and passes that stacktrace to the
sched_switch event when that task schedules back in. It triggers the
"stack" synthetic event that has a stacktrace as its field (called "stack").
~# echo 's:syscall_stack s64 id; unsigned long stack[];' >> dynamic_events
~# echo 'hist:keys=common_pid:s2=stack' >> events/synthetic/stack/trigger
~# echo 'hist:keys=common_pid:s3=$s2,i0=id:onmatch(synthetic.stack).trace(syscall_stack,$i0,$s3)' >> events/raw_syscalls/sys_exit/trigger
The above makes another synthetic event called "syscall_stack" that
attaches the first synthetic event (stack) to the sys_exit trace event and
records the stacktrace from the stack event with the id of the system call
that is exiting.
When enabling this event (or using it in a historgram):
~# echo 1 > events/synthetic/syscall_stack/enable
Produces a kernel crash!
BUG: unable to handle page fault for address: 0000000000400010
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 0 P4D 0
Oops: Oops: 0000 [#1] SMP PTI
CPU: 6 UID: 0 PID: 1257 Comm: bash Not tainted 6.16.3+deb14-amd64 #1 PREEMPT(lazy) Debian 6.16.3-1
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.17.0-debian-1.17.0-1 04/01/2014
RIP: 0010:trace_event_raw_event_synth+0x90/0x380
Code: c5 00 00 00 00 85 d2 0f 84 e1 00 00 00 31 db eb 34 0f 1f 00 66 66 2e 0f 1f 84 00 00 00 00 00 66 66 2e 0f 1f 84 00 00 00 00 00 <49> 8b 04 24 48 83 c3 01 8d 0c c5 08 00 00 00 01 cd 41 3b 5d 40 0f
RSP: 0018:ffffd2670388f958 EFLAGS: 00010202
RAX: ffff8ba1065cc100 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000001 RSI: fffff266ffda7b90 RDI: ffffd2670388f9b0
RBP: 0000000000000010 R08: ffff8ba104e76000 R09: ffffd2670388fa50
R10: ffff8ba102dd42e0 R11: ffffffff9a908970 R12: 0000000000400010
R13: ffff8ba10a246400 R14: ffff8ba10a710220 R15: fffff266ffda7b90
FS: 00007fa3bc63f740(0000) GS:ffff8ba2e0f48000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000400010 CR3: 0000000107f9e003 CR4: 0000000000172ef0
Call Trace:
<TASK>
? __tracing_map_insert+0x208/0x3a0
action_trace+0x67/0x70
event_hist_trigger+0x633/0x6d0
event_triggers_call+0x82/0x130
trace_event_buffer_commit+0x19d/0x250
trace_event_raw_event_sys_exit+0x62/0xb0
syscall_exit_work+0x9d/0x140
do_syscall_64+0x20a/0x2f0
? trace_event_raw_event_sched_switch+0x12b/0x170
? save_fpregs_to_fpstate+0x3e/0x90
? _raw_spin_unlock+0xe/0x30
? finish_task_switch.isra.0+0x97/0x2c0
? __rseq_handle_notify_resume+0xad/0x4c0
? __schedule+0x4b8/0xd00
? restore_fpregs_from_fpstate+0x3c/0x90
? switch_fpu_return+0x5b/0xe0
? do_syscall_64+0x1ef/0x2f0
? do_fault+0x2e9/0x540
? __handle_mm_fault+0x7d1/0xf70
? count_memcg_events+0x167/0x1d0
? handle_mm_fault+0x1d7/0x2e0
? do_user_addr_fault+0x2c3/0x7f0
entry_SYSCALL_64_after_hwframe+0x76/0x7e
The reason is that the stacktrace field is not labeled as such, and is
treated as a normal field and not as a dynamic event that it is.
In trace_event_raw_event_synth() the event is field is still treated as a
dynamic array, but the retrieval of the data is considered a normal field,
and the reference is just the meta data:
// Meta data is retrieved instead of a dynamic array
str_val = (char *)(long)var_ref_vals[val_idx];
// Then when it tries to process it:
len = *((unsigned long *)str_val) + 1;
It triggers a kernel page fault.
To fix this, first when defining the fields of the first synthetic event,
set the filter type to FILTER_STACKTRACE. This is used later by the second
synthetic event to know that this field is a stacktrace. When creating
the field of the new synthetic event, have it use this FILTER_STACKTRACE
to know to create a stacktrace field to copy the stacktrace into.
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Tom Zanussi <zanussi@kernel.org>
Link: https://patch.msgid.link/20260122194824.6905a38e@gandalf.local.home
Fixes: 00cf3d672a9d ("tracing: Allow synthetic events to pass around stacktraces")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit be55257fab181b93af38f8c4b1b3cb453a78d742 upstream.
The pg_remaining calculation in ftrace_process_locs() assumes that
ENTRIES_PER_PAGE multiplied by 2^order equals the actual capacity of the
allocated page group. However, ENTRIES_PER_PAGE is PAGE_SIZE / ENTRY_SIZE
(integer division). When PAGE_SIZE is not a multiple of ENTRY_SIZE (e.g.
4096 / 24 = 170 with remainder 16), high-order allocations (like 256 pages)
have significantly more capacity than 256 * 170. This leads to pg_remaining
being underestimated, which in turn makes skip (derived from skipped -
pg_remaining) larger than expected, causing the WARN(skip != remaining)
to trigger.
Extra allocated pages for ftrace: 2 with 654 skipped
WARNING: CPU: 0 PID: 0 at kernel/trace/ftrace.c:7295 ftrace_process_locs+0x5bf/0x5e0
A similar problem in ftrace_allocate_records() can result in allocating
too many pages. This can trigger the second warning in
ftrace_process_locs().
Extra allocated pages for ftrace
WARNING: CPU: 0 PID: 0 at kernel/trace/ftrace.c:7276 ftrace_process_locs+0x548/0x580
Use the actual capacity of a page group to determine the number of pages
to allocate. Have ftrace_allocate_pages() return the number of allocated
pages to avoid having to calculate it. Use the actual page group capacity
when validating the number of unused pages due to skipped entries.
Drop the definition of ENTRIES_PER_PAGE since it is no longer used.
Cc: stable@vger.kernel.org
Fixes: 4a3efc6baff93 ("ftrace: Update the mcount_loc check of skipped entries")
Link: https://patch.msgid.link/20260113152243.3557219-1-linux@roeck-us.net
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 1e2ed4bfd50ace3c4272cfab7e9aa90956fb7ae0 ]
The ftrace_dump_on_oops string is not used outside of trace.c so
make it static to avoid the export warning from sparse:
kernel/trace/trace.c:141:6: warning: symbol 'ftrace_dump_on_oops' was not declared. Should it be static?
Fixes: dd293df6395a2 ("tracing: Move trace sysctls into trace.c")
Link: https://patch.msgid.link/20260106231054.84270-1-ben.dooks@codethink.co.uk
Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit 5f1ef0dfcb5b7f4a91a9b0e0ba533efd9f7e2cdb upstream.
A bug was reported about an infinite recursion caused by tracing the rcu
events with the kernel stack trace trigger enabled. The stack trace code
called back into RCU which then called the stack trace again.
Expand the ftrace recursion protection to add a set of bits to protect
events from recursion. Each bit represents the context that the event is
in (normal, softirq, interrupt and NMI).
Have the stack trace code use the interrupt context to protect against
recursion.
Note, the bug showed an issue in both the RCU code as well as the tracing
stacktrace code. This only handles the tracing stack trace side of the
bug. The RCU fix will be handled separately.
Link: https://lore.kernel.org/all/20260102122807.7025fc87@gandalf.local.home/
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Link: https://patch.msgid.link/20260105203141.515cd49f@gandalf.local.home
Reported-by: Yao Kai <yaokai34@huawei.com>
Tested-by: Yao Kai <yaokai34@huawei.com>
Fixes: 5f5fa7ea89dc ("rcu: Don't use negative nesting depth in __rcu_read_unlock()")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 1650a1b6cb1ae6cb99bb4fce21b30ebdf9fc238e upstream.
When registering ftrace_graph, check if ftrace_pids_enabled is active.
If enabled, assign entryfunc to fgraph_pid_func to ensure filtering
is performed before executing the saved original entry function.
Cc: stable@vger.kernel.org
Cc: <wang.yaxin@zte.com.cn>
Cc: <mhiramat@kernel.org>
Cc: <mark.rutland@arm.com>
Cc: <mathieu.desnoyers@efficios.com>
Cc: <zhang.run@zte.com.cn>
Cc: <yang.yang29@zte.com.cn>
Link: https://patch.msgid.link/20251126173331679XGVF98NLhyLJRdtNkVZ6w@zte.com.cn
Fixes: df3ec5da6a1e7 ("function_graph: Add pid tracing back to function graph tracer")
Signed-off-by: Shengming Hu <hu.shengming@zte.com.cn>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit b5d6d3f73d0bac4a7e3a061372f6da166fc6ee5c upstream.
The ftrace_pids_enabled(op) check relies on op->private being properly
initialized, but fgraph_ops's underlying ftrace_ops->private was left
uninitialized. This caused ftrace_pids_enabled() to always return false,
effectively disabling PID filtering for function graph tracing.
Fix this by copying src_ops->private to dst_ops->private in
fgraph_init_ops(), ensuring PID filter state is correctly propagated.
Cc: stable@vger.kernel.org
Cc: <wang.yaxin@zte.com.cn>
Cc: <mhiramat@kernel.org>
Cc: <mark.rutland@arm.com>
Cc: <mathieu.desnoyers@efficios.com>
Cc: <zhang.run@zte.com.cn>
Cc: <yang.yang29@zte.com.cn>
Fixes: c132be2c4fcc1 ("function_graph: Have the instances use their own ftrace_ops for filtering")
Link: https://patch.msgid.link/20251126172926004y3hC8QyU4WFOjBkU_UxLC@zte.com.cn
Signed-off-by: Shengming Hu <hu.shengming@zte.com.cn>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 47ef834209e5981f443240d8a8b45bf680df22aa upstream.
The commit 4d38328eb442d ("tracing: Fix synth event printk format for str
fields") replaced "%.*s" with "%s" but missed removing the number size of
the dynamic and static strings. The commit e1a453a57bc7 ("tracing: Do not
add length to print format in synthetic events") fixed the dynamic part
but did not fix the static part. That is, with the commands:
# echo 's:wake_lat char[] wakee; u64 delta;' >> /sys/kernel/tracing/dynamic_events
# echo 'hist:keys=pid:ts=common_timestamp.usecs if !(common_flags & 0x18)' > /sys/kernel/tracing/events/sched/sched_waking/trigger
# echo 'hist:keys=next_pid:delta=common_timestamp.usecs-$ts:onmatch(sched.sched_waking).trace(wake_lat,next_comm,$delta)' > /sys/kernel/tracing/events/sched/sched_switch/trigger
That caused the output of:
<idle>-0 [001] d..5. 193.428167: wake_lat: wakee=(efault)sshd-sessiondelta=155
sshd-session-879 [001] d..5. 193.811080: wake_lat: wakee=(efault)kworker/u34:5delta=58
<idle>-0 [002] d..5. 193.811198: wake_lat: wakee=(efault)bashdelta=91
The commit e1a453a57bc7 fixed the part where the synthetic event had
"char[] wakee". But if one were to replace that with a static size string:
# echo 's:wake_lat char[16] wakee; u64 delta;' >> /sys/kernel/tracing/dynamic_events
Where "wakee" is defined as "char[16]" and not "char[]" making it a static
size, the code triggered the "(efaul)" again.
Remove the added STR_VAR_LEN_MAX size as the string is still going to be
nul terminated.
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Douglas Raillard <douglas.raillard@arm.com>
Link: https://patch.msgid.link/20251204151935.5fa30355@gandalf.local.home
Fixes: e1a453a57bc7 ("tracing: Do not add length to print format in synthetic events")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit ef7f38df890f5dcd2ae62f8dbde191d72f3bebae upstream.
Synthetic events currently do not have a function to register perf events.
This leads to calling the tracepoint register functions with a NULL
function pointer which triggers:
------------[ cut here ]------------
WARNING: kernel/tracepoint.c:175 at tracepoint_add_func+0x357/0x370, CPU#2: perf/2272
Modules linked in: kvm_intel kvm irqbypass
CPU: 2 UID: 0 PID: 2272 Comm: perf Not tainted 6.18.0-ftest-11964-ge022764176fc-dirty #323 PREEMPTLAZY
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.17.0-debian-1.17.0-1 04/01/2014
RIP: 0010:tracepoint_add_func+0x357/0x370
Code: 28 9c e8 4c 0b f5 ff eb 0f 4c 89 f7 48 c7 c6 80 4d 28 9c e8 ab 89 f4 ff 31 c0 5b 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc <0f> 0b 49 c7 c6 ea ff ff ff e9 ee fe ff ff 0f 0b e9 f9 fe ff ff 0f
RSP: 0018:ffffabc0c44d3c40 EFLAGS: 00010246
RAX: 0000000000000001 RBX: ffff9380aa9e4060 RCX: 0000000000000000
RDX: 000000000000000a RSI: ffffffff9e1d4a98 RDI: ffff937fcf5fd6c8
RBP: 0000000000000001 R08: 0000000000000007 R09: ffff937fcf5fc780
R10: 0000000000000003 R11: ffffffff9c193910 R12: 000000000000000a
R13: ffffffff9e1e5888 R14: 0000000000000000 R15: ffffabc0c44d3c78
FS: 00007f6202f5f340(0000) GS:ffff93819f00f000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055d3162281a8 CR3: 0000000106a56003 CR4: 0000000000172ef0
Call Trace:
<TASK>
tracepoint_probe_register+0x5d/0x90
synth_event_reg+0x3c/0x60
perf_trace_event_init+0x204/0x340
perf_trace_init+0x85/0xd0
perf_tp_event_init+0x2e/0x50
perf_try_init_event+0x6f/0x230
? perf_event_alloc+0x4bb/0xdc0
perf_event_alloc+0x65a/0xdc0
__se_sys_perf_event_open+0x290/0x9f0
do_syscall_64+0x93/0x7b0
? entry_SYSCALL_64_after_hwframe+0x76/0x7e
? trace_hardirqs_off+0x53/0xc0
entry_SYSCALL_64_after_hwframe+0x76/0x7e
Instead, have the code return -ENODEV, which doesn't warn and has perf
error out with:
# perf record -e synthetic:futex_wait
Error:
The sys_perf_event_open() syscall returned with 19 (No such device) for event (synthetic:futex_wait).
"dmesg | grep -i perf" may provide additional information.
Ideally perf should support synthetic events, but for now just fix the
warning. The support can come later.
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://patch.msgid.link/20251216182440.147e4453@gandalf.local.home
Fixes: 4b147936fa509 ("tracing: Add support for 'synthetic' events")
Reported-by: Ian Rogers <irogers@google.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit ac44dcc788b950606793e8f9690c30925f59df02 ]
Commit 37cce22dbd51 ("bpf: verifier: Refactor helper access type
tracking") started distinguishing read vs write accesses performed by
helpers.
The second argument of bpf_d_path() is a pointer to a buffer that the
helper fills with the resulting path. However, its prototype currently
uses ARG_PTR_TO_MEM without MEM_WRITE.
Before 37cce22dbd51, helper accesses were conservatively treated as
potential writes, so this mismatch did not cause issues. Since that
commit, the verifier may incorrectly assume that the buffer contents
are unchanged across the helper call and base its optimizations on this
wrong assumption. This can lead to misbehaviour in BPF programs that
read back the buffer, such as prefix comparisons on the returned path.
Fix this by marking the second argument of bpf_d_path() as
ARG_PTR_TO_MEM | MEM_WRITE so that the verifier correctly models the
write to the caller-provided buffer.
Fixes: 37cce22dbd51 ("bpf: verifier: Refactor helper access type tracking")
Co-developed-by: Zesen Liu <ftyg@live.com>
Signed-off-by: Zesen Liu <ftyg@live.com>
Co-developed-by: Peili Gao <gplhust955@gmail.com>
Signed-off-by: Peili Gao <gplhust955@gmail.com>
Co-developed-by: Haoran Ni <haoran.ni.cs@gmail.com>
Signed-off-by: Haoran Ni <haoran.ni.cs@gmail.com>
Signed-off-by: Shuran Liu <electronlsr@gmail.com>
Reviewed-by: Matt Bobrowski <mattbobrowski@google.com>
Link: https://lore.kernel.org/r/20251206141210.3148-2-electronlsr@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull ring-buffer fix from Steven Rostedt:
- Do not allow mmapped ring buffer to be split
When the ring buffer VMA is split by a partial munmap or a MAP_FIXED,
the kernel calls vm_ops->close() on each portion. This causes the
ring_buffer_unmap() to be called multiple times. This causes
subsequent calls to return -ENODEV and triggers a warning.
There's no reason to allow user space to split up memory mapping of
the ring buffer. Have it return -EINVAL when that happens.
* tag 'trace-ringbuffer-v6.18-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
tracing: Fix WARN_ON in tracing_buffers_mmap_close for split VMAs
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When a VMA is split (e.g., by partial munmap or MAP_FIXED), the kernel
calls vm_ops->close on each portion. For trace buffer mappings, this
results in ring_buffer_unmap() being called multiple times while
ring_buffer_map() was only called once.
This causes ring_buffer_unmap() to return -ENODEV on subsequent calls
because user_mapped is already 0, triggering a WARN_ON.
Trace buffer mappings cannot support partial mappings because the ring
buffer structure requires the complete buffer including the meta page.
Fix this by adding a may_split callback that returns -EINVAL to prevent
VMA splits entirely.
Cc: stable@vger.kernel.org
Fixes: cf9f0f7c4c5bb ("tracing: Allow user-space mapping of the ring-buffer")
Link: https://patch.msgid.link/20251119064019.25904-1-kartikey406@gmail.com
Closes: https://syzkaller.appspot.com/bug?extid=a72c325b042aae6403c7
Tested-by: syzbot+a72c325b042aae6403c7@syzkaller.appspotmail.com
Reported-by: syzbot+a72c325b042aae6403c7@syzkaller.appspotmail.com
Signed-off-by: Deepanshu Kartikey <kartikey406@gmail.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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Pull bpf fixes from Alexei Starovoitov:
- Fix interaction between livepatch and BPF fexit programs (Song Liu)
With Steven and Masami acks.
- Fix stack ORC unwind from BPF kprobe_multi (Jiri Olsa)
With Steven and Masami acks.
- Fix out of bounds access in widen_imprecise_scalars() in the verifier
(Eduard Zingerman)
- Fix conflicts between MPTCP and BPF sockmap (Jiayuan Chen)
- Fix net_sched storage collision with BPF data_meta/data_end (Eric
Dumazet)
- Add _impl suffix to BPF kfuncs with implicit args to avoid breaking
them in bpf-next when KF_IMPLICIT_ARGS is added (Mykyta Yatsenko)
* tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
selftests/bpf: Test widen_imprecise_scalars() with different stack depth
bpf: account for current allocated stack depth in widen_imprecise_scalars()
bpf: Add bpf_prog_run_data_pointers()
selftests/bpf: Add mptcp test with sockmap
mptcp: Fix proto fallback detection with BPF
mptcp: Disallow MPTCP subflows from sockmap
selftests/bpf: Add stacktrace ips test for raw_tp
selftests/bpf: Add stacktrace ips test for kprobe_multi/kretprobe_multi
x86/fgraph,bpf: Fix stack ORC unwind from kprobe_multi return probe
Revert "perf/x86: Always store regs->ip in perf_callchain_kernel()"
bpf: add _impl suffix for bpf_stream_vprintk() kfunc
bpf:add _impl suffix for bpf_task_work_schedule* kfuncs
selftests/bpf: Add tests for livepatch + bpf trampoline
ftrace: bpf: Fix IPMODIFY + DIRECT in modify_ftrace_direct()
ftrace: Fix BPF fexit with livepatch
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git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull tracing fixes from Steven Rostedt:
- Check for reader catching up in ring_buffer_map_get_reader()
If the reader catches up to the writer in the memory mapped ring
buffer then calling rb_get_reader_page() will return NULL as there's
no pages left. But this isn't checked for before calling
rb_get_reader_page() and the return of NULL causes a warning.
If it is detected that the reader caught up to the writer, then
simply exit the routine
- Fix memory leak in histogram create_field_var()
The couple of the error paths in create_field_var() did not properly
clean up what was allocated. Make sure everything is freed properly
on error
- Fix help message of tools latency_collector
The help message incorrectly stated that "-t" was the same as
"--threads" whereas "--threads" is actually represented by "-e"
* tag 'trace-v6.18-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
tracing/tools: Fix incorrcet short option in usage text for --threads
tracing: Fix memory leaks in create_field_var()
ring-buffer: Do not warn in ring_buffer_map_get_reader() when reader catches up
|
|
The function create_field_var() allocates memory for 'val' through
create_hist_field() inside parse_atom(), and for 'var' through
create_var(), which in turn allocates var->type and var->var.name
internally. Simply calling kfree() to release these structures will
result in memory leaks.
Use destroy_hist_field() to properly free 'val', and explicitly release
the memory of var->type and var->var.name before freeing 'var' itself.
Link: https://patch.msgid.link/20251106120132.3639920-1-zilin@seu.edu.cn
Fixes: 02205a6752f22 ("tracing: Add support for 'field variables'")
Signed-off-by: Zilin Guan <zilin@seu.edu.cn>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
|
|
The function ring_buffer_map_get_reader() is a bit more strict than the
other get reader functions, and except for certain situations the
rb_get_reader_page() should not return NULL. If it does, it triggers a
warning.
This warning was triggering but after looking at why, it was because
another acceptable situation was happening and it wasn't checked for.
If the reader catches up to the writer and there's still data to be read
on the reader page, then the rb_get_reader_page() will return NULL as
there's no new page to get.
In this situation, the reader page should not be updated and no warning
should trigger.
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Vincent Donnefort <vdonnefort@google.com>
Reported-by: syzbot+92a3745cea5ec6360309@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/690babec.050a0220.baf87.0064.GAE@google.com/
Link: https://lore.kernel.org/20251016132848.1b11bb37@gandalf.local.home
Fixes: 117c39200d9d7 ("ring-buffer: Introducing ring-buffer mapping functions")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
|
|
__unregister_trace_fprobe() checks tf->tuser to put it when removing
tprobe. However, disable_trace_fprobe() does not use it and only calls
unregister_fprobe(). Thus it forgets to disable tracepoint_user.
If the trace_fprobe has tuser, put it for unregistering the tracepoint
callbacks when disabling tprobe correctly.
Link: https://lore.kernel.org/all/176244794466.155515.3971904050506100243.stgit@devnote2/
Fixes: 2867495dea86 ("tracing: tprobe-events: Register tracepoint when enable tprobe event")
Cc: stable@vger.kernel.org
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Tested-by: Beau Belgrave <beaub@linux.microsoft.com>
Reviewed-by: Beau Belgrave <beaub@linux.microsoft.com>
|
|
Since __tracepoint_user_init() calls tracepoint_user_register() without
initializing tuser->tpoint with given tracpoint, it does not register
tracepoint stub function as callback correctly, and tprobe does not work.
Initializing tuser->tpoint correctly before tracepoint_user_register()
so that it sets up tracepoint callback.
I confirmed below example works fine again.
echo "t sched_switch preempt prev_pid=prev->pid next_pid=next->pid" > /sys/kernel/tracing/dynamic_events
echo 1 > /sys/kernel/tracing/events/tracepoints/sched_switch/enable
cat /sys/kernel/tracing/trace_pipe
Link: https://lore.kernel.org/all/176244793514.155515.6466348656998627773.stgit@devnote2/
Fixes: 2867495dea86 ("tracing: tprobe-events: Register tracepoint when enable tprobe event")
Reported-by: Beau Belgrave <beaub@linux.microsoft.com>
Cc: stable@vger.kernel.org
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Tested-by: Beau Belgrave <beaub@linux.microsoft.com>
Reviewed-by: Beau Belgrave <beaub@linux.microsoft.com>
|
|
ftrace_hash_ipmodify_enable() checks IPMODIFY and DIRECT ftrace_ops on
the same kernel function. When needed, ftrace_hash_ipmodify_enable()
calls ops->ops_func() to prepare the direct ftrace (BPF trampoline) to
share the same function as the IPMODIFY ftrace (livepatch).
ftrace_hash_ipmodify_enable() is called in register_ftrace_direct() path,
but not called in modify_ftrace_direct() path. As a result, the following
operations will break livepatch:
1. Load livepatch to a kernel function;
2. Attach fentry program to the kernel function;
3. Attach fexit program to the kernel function.
After 3, the kernel function being used will not be the livepatched
version, but the original version.
Fix this by adding __ftrace_hash_update_ipmodify() to
__modify_ftrace_direct() and adjust some logic around the call.
Signed-off-by: Song Liu <song@kernel.org>
Reviewed-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20251027175023.1521602-3-song@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
|
|
When livepatch is attached to the same function as bpf trampoline with
a fexit program, bpf trampoline code calls register_ftrace_direct()
twice. The first time will fail with -EAGAIN, and the second time it
will succeed. This requires register_ftrace_direct() to unregister
the address on the first attempt. Otherwise, the bpf trampoline cannot
attach. Here is an easy way to reproduce this issue:
insmod samples/livepatch/livepatch-sample.ko
bpftrace -e 'fexit:cmdline_proc_show {}'
ERROR: Unable to attach probe: fexit:vmlinux:cmdline_proc_show...
Fix this by cleaning up the hash when register_ftrace_function_nolock hits
errors.
Also, move the code that resets ops->func and ops->trampoline to the error
path of register_ftrace_direct(); and add a helper function reset_direct()
in register_ftrace_direct() and unregister_ftrace_direct().
Fixes: d05cb470663a ("ftrace: Fix modification of direct_function hash while in use")
Cc: stable@vger.kernel.org # v6.6+
Reported-by: Andrey Grodzovsky <andrey.grodzovsky@crowdstrike.com>
Closes: https://lore.kernel.org/live-patching/c5058315a39d4615b333e485893345be@crowdstrike.com/
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Cc: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-and-tested-by: Andrey Grodzovsky <andrey.grodzovsky@crowdstrike.com>
Signed-off-by: Song Liu <song@kernel.org>
Reviewed-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20251027175023.1521602-2-song@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
|
|
There is no page fault without MMU. Compiling the rtapp/pagefault monitor
without CONFIG_MMU fails as page fault tracepoints' definitions are not
available.
Make rtapp/pagefault monitor depends on CONFIG_MMU.
Fixes: 9162620eb604 ("rv: Add rtapp_pagefault monitor")
Signed-off-by: Nam Cao <namcao@linutronix.de>
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202509260455.6Z9Vkty4-lkp@intel.com/
Cc: stable@vger.kernel.org
Reviewed-by: Gabriele Monaco <gmonaco@redhat.com>
Link: https://lore.kernel.org/r/20251002082317.973839-1-namcao@linutronix.de
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
|
|
The callbacks in enabled_monitors_seq_ops are inconsistent. Some treat the
iterator as struct rv_monitor *, while others treat the iterator as struct
list_head *.
This causes a wrong type cast and crashes the system as reported by Nathan.
Convert everything to use struct list_head * as iterator. This also makes
enabled_monitors consistent with available_monitors.
Fixes: de090d1ccae1 ("rv: Fix wrong type cast in enabled_monitors_next()")
Reported-by: Nathan Chancellor <nathan@kernel.org>
Closes: https://lore.kernel.org/linux-trace-kernel/20250923002004.GA2836051@ax162/
Signed-off-by: Nam Cao <namcao@linutronix.de>
Cc: stable@vger.kernel.org
Reviewed-by: Gabriele Monaco <gmonaco@redhat.com>
Link: https://lore.kernel.org/r/20251002082235.973099-1-namcao@linutronix.de
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull tracing fixes from Steven Rostedt:
"The previous fix to trace_marker required updating trace_marker_raw as
well. The difference between trace_marker_raw from trace_marker is
that the raw version is for applications to write binary structures
directly into the ring buffer instead of writing ASCII strings. This
is for applications that will read the raw data from the ring buffer
and get the data structures directly. It's a bit quicker than using
the ASCII version.
Unfortunately, it appears that our test suite has several tests that
test writes to the trace_marker file, but lacks any tests to the
trace_marker_raw file (this needs to be remedied). Two issues came
about the update to the trace_marker_raw file that syzbot found:
- Fix tracing_mark_raw_write() to use per CPU buffer
The fix to use the per CPU buffer to copy from user space was
needed for both the trace_maker and trace_maker_raw file.
The fix for reading from user space into per CPU buffers properly
fixed the trace_marker write function, but the trace_marker_raw
file wasn't fixed properly. The user space data was correctly
written into the per CPU buffer, but the code that wrote into the
ring buffer still used the user space pointer and not the per CPU
buffer that had the user space data already written.
- Stop the fortify string warning from writing into trace_marker_raw
After converting the copy_from_user_nofault() into a memcpy(),
another issue appeared. As writes to the trace_marker_raw expects
binary data, the first entry is a 4 byte identifier. The entry
structure is defined as:
struct {
struct trace_entry ent;
int id;
char buf[];
};
The size of this structure is reserved on the ring buffer with:
size = sizeof(*entry) + cnt;
Then it is copied from the buffer into the ring buffer with:
memcpy(&entry->id, buf, cnt);
This use to be a copy_from_user_nofault(), but now converting it to
a memcpy() triggers the fortify-string code, and causes a warning.
The allocated space is actually more than what is copied, as the
cnt used also includes the entry->id portion. Allocating
sizeof(*entry) plus cnt is actually allocating 4 bytes more than
what is needed.
Change the size function to:
size = struct_size(entry, buf, cnt - sizeof(entry->id));
And update the memcpy() to unsafe_memcpy()"
* tag 'trace-v6.18-3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
tracing: Stop fortify-string from warning in tracing_mark_raw_write()
tracing: Fix tracing_mark_raw_write() to use buf and not ubuf
|
|
The way tracing_mark_raw_write() records its data is that it has the
following structure:
struct {
struct trace_entry;
int id;
char buf[];
};
But memcpy(&entry->id, buf, size) triggers the following warning when the
size is greater than the id:
------------[ cut here ]------------
memcpy: detected field-spanning write (size 6) of single field "&entry->id" at kernel/trace/trace.c:7458 (size 4)
WARNING: CPU: 7 PID: 995 at kernel/trace/trace.c:7458 write_raw_marker_to_buffer.isra.0+0x1f9/0x2e0
Modules linked in:
CPU: 7 UID: 0 PID: 995 Comm: bash Not tainted 6.17.0-test-00007-g60b82183e78a-dirty #211 PREEMPT(voluntary)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.17.0-debian-1.17.0-1 04/01/2014
RIP: 0010:write_raw_marker_to_buffer.isra.0+0x1f9/0x2e0
Code: 04 00 75 a7 b9 04 00 00 00 48 89 de 48 89 04 24 48 c7 c2 e0 b1 d1 b2 48 c7 c7 40 b2 d1 b2 c6 05 2d 88 6a 04 01 e8 f7 e8 bd ff <0f> 0b 48 8b 04 24 e9 76 ff ff ff 49 8d 7c 24 04 49 8d 5c 24 08 48
RSP: 0018:ffff888104c3fc78 EFLAGS: 00010292
RAX: 0000000000000000 RBX: 0000000000000006 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 1ffffffff6b363b4 RDI: 0000000000000001
RBP: ffff888100058a00 R08: ffffffffb041d459 R09: ffffed1020987f40
R10: 0000000000000007 R11: 0000000000000001 R12: ffff888100bb9010
R13: 0000000000000000 R14: 00000000000003e3 R15: ffff888134800000
FS: 00007fa61d286740(0000) GS:ffff888286cad000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000560d28d509f1 CR3: 00000001047a4006 CR4: 0000000000172ef0
Call Trace:
<TASK>
tracing_mark_raw_write+0x1fe/0x290
? __pfx_tracing_mark_raw_write+0x10/0x10
? security_file_permission+0x50/0xf0
? rw_verify_area+0x6f/0x4b0
vfs_write+0x1d8/0xdd0
? __pfx_vfs_write+0x10/0x10
? __pfx_css_rstat_updated+0x10/0x10
? count_memcg_events+0xd9/0x410
? fdget_pos+0x53/0x5e0
ksys_write+0x182/0x200
? __pfx_ksys_write+0x10/0x10
? do_user_addr_fault+0x4af/0xa30
do_syscall_64+0x63/0x350
entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7fa61d318687
Code: 48 89 fa 4c 89 df e8 58 b3 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
RSP: 002b:00007ffd87fe0120 EFLAGS: 00000202 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fa61d286740 RCX: 00007fa61d318687
RDX: 0000000000000006 RSI: 0000560d28d509f0 RDI: 0000000000000001
RBP: 0000560d28d509f0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000006
R13: 00007fa61d4715c0 R14: 00007fa61d46ee80 R15: 0000000000000000
</TASK>
---[ end trace 0000000000000000 ]---
This is because fortify string sees that the size of entry->id is only 4
bytes, but it is writing more than that. But this is OK as the
dynamic_array is allocated to handle that copy.
The size allocated on the ring buffer was actually a bit too big:
size = sizeof(*entry) + cnt;
But cnt includes the 'id' and the buffer data, so adding cnt to the size
of *entry actually allocates too much on the ring buffer.
Change the allocation to:
size = struct_size(entry, buf, cnt - sizeof(entry->id));
and the memcpy() to unsafe_memcpy() with an added justification.
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: https://lore.kernel.org/20251011112032.77be18e4@gandalf.local.home
Fixes: 64cf7d058a00 ("tracing: Have trace_marker use per-cpu data to read user space")
Reported-by: syzbot+9a2ede1643175f350105@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/68e973f5.050a0220.1186a4.0010.GAE@google.com/
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
|
|
The fix to use a per CPU buffer to read user space tested only the writes
to trace_marker. But it appears that the selftests are missing tests to
the trace_maker_raw file. The trace_maker_raw file is used by applications
that writes data structures and not strings into the file, and the tools
read the raw ring buffer to process the structures it writes.
The fix that reads the per CPU buffers passes the new per CPU buffer to
the trace_marker file writes, but the update to the trace_marker_raw write
read the data from user space into the per CPU buffer, but then still used
then passed the user space address to the function that records the data.
Pass in the per CPU buffer and not the user space address.
TODO: Add a test to better test trace_marker_raw.
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: https://lore.kernel.org/20251011035243.386098147@kernel.org
Fixes: 64cf7d058a00 ("tracing: Have trace_marker use per-cpu data to read user space")
Reported-by: syzbot+9a2ede1643175f350105@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/68e973f5.050a0220.1186a4.0010.GAE@google.com/
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull tracing clean up and fixes from Steven Rostedt:
- Have osnoise tracer use memdup_user_nul()
The function osnoise_cpus_write() open codes a kmalloc() and then a
copy_from_user() and then adds a nul byte at the end which is the
same as simply using memdup_user_nul().
- Fix wakeup and irq tracers when failing to acquire calltime
When the wakeup and irq tracers use the function graph tracer for
tracing function times, it saves a timestamp into the fgraph shadow
stack. It is possible that this could fail to be stored. If that
happens, it exits the routine early. These functions also disable
nesting of the operations by incremeting the data "disable" counter.
But if the calltime exits out early, it never increments the counter
back to what it needs to be.
Since there's only a couple of lines of code that does work after
acquiring the calltime, instead of exiting out early, reverse the if
statement to be true if calltime is acquired, and place the code that
is to be done within that if block. The clean up will always be done
after that.
- Fix ring_buffer_map() return value on failure of __rb_map_vma()
If __rb_map_vma() fails in ring_buffer_map(), it does not return an
error. This means the caller will be working against a bad vma
mapping. Have ring_buffer_map() return an error when __rb_map_vma()
fails.
- Fix regression of writing to the trace_marker file
A bug fix was made to change __copy_from_user_inatomic() to
copy_from_user_nofault() in the trace_marker write function. The
trace_marker file is used by applications to write into it (usually
with a file descriptor opened at the start of the program) to record
into the tracing system. It's usually used in critical sections so
the write to trace_marker is highly optimized.
The reason for copying in an atomic section is that the write
reserves space on the ring buffer and then writes directly into it.
After it writes, it commits the event. The time between reserve and
commit must have preemption disabled.
The trace marker write does not have any locking nor can it allocate
due to the nature of it being a critical path.
Unfortunately, converting __copy_from_user_inatomic() to
copy_from_user_nofault() caused a regression in Android. Now all the
writes from its applications trigger the fault that is rejected by
the _nofault() version that wasn't rejected by the _inatomic()
version. Instead of getting data, it now just gets a trace buffer
filled with:
tracing_mark_write: <faulted>
To fix this, on opening of the trace_marker file, allocate per CPU
buffers that can be used by the write call. Then when entering the
write call, do the following:
preempt_disable();
cpu = smp_processor_id();
buffer = per_cpu_ptr(cpu_buffers, cpu);
do {
cnt = nr_context_switches_cpu(cpu);
migrate_disable();
preempt_enable();
ret = copy_from_user(buffer, ptr, size);
preempt_disable();
migrate_enable();
} while (!ret && cnt != nr_context_switches_cpu(cpu));
if (!ret)
ring_buffer_write(buffer);
preempt_enable();
This works similarly to seqcount. As it must enabled preemption to do
a copy_from_user() into a per CPU buffer, if it gets preempted, the
buffer could be corrupted by another task.
To handle this, read the number of context switches of the current
CPU, disable migration, enable preemption, copy the data from user
space, then immediately disable preemption again. If the number of
context switches is the same, the buffer is still valid. Otherwise it
must be assumed that the buffer may have been corrupted and it needs
to try again.
Now the trace_marker write can get the user data even if it has to
fault it in, and still not grab any locks of its own.
* tag 'trace-v6.18-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
tracing: Have trace_marker use per-cpu data to read user space
ring buffer: Propagate __rb_map_vma return value to caller
tracing: Fix irqoff tracers on failure of acquiring calltime
tracing: Fix wakeup tracers on failure of acquiring calltime
tracing/osnoise: Replace kmalloc + copy_from_user with memdup_user_nul
|
|
It was reported that using __copy_from_user_inatomic() can actually
schedule. Which is bad when preemption is disabled. Even though there's
logic to check in_atomic() is set, but this is a nop when the kernel is
configured with PREEMPT_NONE. This is due to page faulting and the code
could schedule with preemption disabled.
Link: https://lore.kernel.org/all/20250819105152.2766363-1-luogengkun@huaweicloud.com/
The solution was to change the __copy_from_user_inatomic() to
copy_from_user_nofault(). But then it was reported that this caused a
regression in Android. There's several applications writing into
trace_marker() in Android, but now instead of showing the expected data,
it is showing:
tracing_mark_write: <faulted>
After reverting the conversion to copy_from_user_nofault(), Android was
able to get the data again.
Writes to the trace_marker is a way to efficiently and quickly enter data
into the Linux tracing buffer. It takes no locks and was designed to be as
non-intrusive as possible. This means it cannot allocate memory, and must
use pre-allocated data.
A method that is actively being worked on to have faultable system call
tracepoints read user space data is to allocate per CPU buffers, and use
them in the callback. The method uses a technique similar to seqcount.
That is something like this:
preempt_disable();
cpu = smp_processor_id();
buffer = this_cpu_ptr(&pre_allocated_cpu_buffers, cpu);
do {
cnt = nr_context_switches_cpu(cpu);
migrate_disable();
preempt_enable();
ret = copy_from_user(buffer, ptr, size);
preempt_disable();
migrate_enable();
} while (!ret && cnt != nr_context_switches_cpu(cpu));
if (!ret)
ring_buffer_write(buffer);
preempt_enable();
It's a little more involved than that, but the above is the basic logic.
The idea is to acquire the current CPU buffer, disable migration, and then
enable preemption. At this moment, it can safely use copy_from_user().
After reading the data from user space, it disables preemption again. It
then checks to see if there was any new scheduling on this CPU. If there
was, it must assume that the buffer was corrupted by another task. If
there wasn't, then the buffer is still valid as only tasks in preemptable
context can write to this buffer and only those that are running on the
CPU.
By using this method, where trace_marker open allocates the per CPU
buffers, trace_marker writes can access user space and even fault it in,
without having to allocate or take any locks of its own.
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Luo Gengkun <luogengkun@huaweicloud.com>
Cc: Wattson CI <wattson-external@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/20251008124510.6dba541a@gandalf.local.home
Fixes: 3d62ab32df065 ("tracing: Fix tracing_marker may trigger page fault during preempt_disable")
Reported-by: Runping Lai <runpinglai@google.com>
Tested-by: Runping Lai <runpinglai@google.com>
Closes: https://lore.kernel.org/linux-trace-kernel/20251007003417.3470979-2-runpinglai@google.com/
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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The return value from `__rb_map_vma()`, which rejects writable or
executable mappings (VM_WRITE, VM_EXEC, or !VM_MAYSHARE), was being
ignored. As a result the caller of `__rb_map_vma` always returned 0
even when the mapping had actually failed, allowing it to proceed
with an invalid VMA.
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/20251008172516.20697-1-ankitkhushwaha.linux@gmail.com
Fixes: 117c39200d9d7 ("ring-buffer: Introducing ring-buffer mapping functions")
Reported-by: syzbot+ddc001b92c083dbf2b97@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?id=194151be8eaebd826005329b2e123aecae714bdb
Signed-off-by: Ankit Khushwaha <ankitkhushwaha.linux@gmail.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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The functions irqsoff_graph_entry() and irqsoff_graph_return() both call
func_prolog_dec() that will test if the data->disable is already set and
if not, increment it and return. If it was set, it returns false and the
caller exits.
The caller of this function must decrement the disable counter, but misses
doing so if the calltime fails to be acquired.
Instead of exiting out when calltime is NULL, change the logic to do the
work if it is not NULL and still do the clean up at the end of the
function if it is NULL.
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/20251008114943.6f60f30f@gandalf.local.home
Fixes: a485ea9e3ef3 ("tracing: Fix irqsoff and wakeup latency tracers when using function graph")
Reported-by: Sasha Levin <sashal@kernel.org>
Closes: https://lore.kernel.org/linux-trace-kernel/20251006175848.1906912-2-sashal@kernel.org/
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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The functions wakeup_graph_entry() and wakeup_graph_return() both call
func_prolog_preempt_disable() that will test if the data->disable is
already set and if not, increment it and disable preemption. If it was
set, it returns false and the caller exits.
The caller of this function must decrement the disable counter, but misses
doing so if the calltime fails to be acquired.
Instead of exiting out when calltime is NULL, change the logic to do the
work if it is not NULL and still do the clean up at the end of the
function if it is NULL.
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/20251008114835.027b878a@gandalf.local.home
Fixes: a485ea9e3ef3 ("tracing: Fix irqsoff and wakeup latency tracers when using function graph")
Reported-by: Sasha Levin <sashal@kernel.org>
Closes: https://lore.kernel.org/linux-trace-kernel/20251006175848.1906912-1-sashal@kernel.org/
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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Replace kmalloc() followed by copy_from_user() with memdup_user_nul() to
simplify and improve osnoise_cpus_write(). Remove the manual
NUL-termination.
No functional changes intended.
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/20251001130907.364673-2-thorsten.blum@linux.dev
Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull tracing updates from Steven Rostedt:
- Use READ_ONCE() and WRITE_ONCE() instead of RCU for syscall
tracepoints
Individual system call trace events are pseudo events attached to the
raw_syscall trace events that just trace the entry and exit of all
system calls. When any of these individual system call trace events
get enabled, an element in an array indexed by the system call number
is assigned to the trace file that defines how to trace it. When the
trace event triggers, it reads this array and if the array has an
element, it uses that trace file to know what to write it (the trace
file defines the output format of the corresponding system call).
The issue is that it uses rcu_dereference_ptr() and marks the
elements of the array as using RCU. This is incorrect. There is no
RCU synchronization here. The event file that is pointed to has a
completely different way to make sure its freed properly. The reading
of the array during the system call trace event is only to know if
there is a value or not. If not, it does nothing (it means this
system call isn't being traced). If it does, it uses the information
to store the system call data.
The RCU usage here can simply be replaced by READ_ONCE() and
WRITE_ONCE() macros.
- Have the system call trace events use "0x" for hex values
Some system call trace events display hex values but do not have "0x"
in front of it. Seeing "count: 44" can be assumed that it is 44
decimal when in actuality it is 44 hex (68 decimal). Display "0x44"
instead.
- Use vmalloc_array() in tracing_map_sort_entries()
The function tracing_map_sort_entries() used array_size() and
vmalloc() when it could have simply used vmalloc_array().
- Use for_each_online_cpu() in trace_osnoise.c()
Instead of open coding for_each_cpu(cpu, cpu_online_mask), use
for_each_online_cpu().
- Move the buffer field in struct trace_seq to the end
The buffer field in struct trace_seq is architecture dependent in
size, and caused padding for the fields after it. By moving the
buffer to the end of the structure, it compacts the trace_seq
structure better.
- Remove redundant zeroing of cmdline_idx field in
saved_cmdlines_buffer()
The structure that contains cmdline_idx is zeroed by memset(), no
need to explicitly zero any of its fields after that.
- Use system_percpu_wq instead of system_wq in user_event_mm_remove()
As system_wq is being deprecated, use the new wq.
- Add cond_resched() is ftrace_module_enable()
Some modules have a lot of functions (thousands of them), and the
enabling of those functions can take some time. On non preemtable
kernels, it was triggering a watchdog timeout. Add a cond_resched()
to prevent that.
- Add a BUILD_BUG_ON() to make sure PID_MAX_DEFAULT is always a power
of 2
There's code that depends on PID_MAX_DEFAULT being a power of 2 or it
will break. If in the future that changes, make sure the build fails
to ensure that the code is fixed that depends on this.
- Grab mutex_lock() before ever exiting s_start()
The s_start() function is a seq_file start routine. As s_stop() is
always called even if s_start() fails, and s_stop() expects the
event_mutex to be held as it will always release it. That mutex must
always be taken in s_start() even if that function fails.
* tag 'trace-v6.18' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
tracing: Fix lock imbalance in s_start() memory allocation failure path
tracing: Ensure optimized hashing works
ftrace: Fix softlockup in ftrace_module_enable
tracing: replace use of system_wq with system_percpu_wq
tracing: Remove redundant 0 value initialization
tracing: Move buffer in trace_seq to end of struct
tracing/osnoise: Use for_each_online_cpu() instead of for_each_cpu()
tracing: Use vmalloc_array() to improve code
tracing: Have syscall trace events show "0x" for values greater than 10
tracing: Replace syscall RCU pointer assignment with READ/WRITE_ONCE()
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