| Age | Commit message (Collapse) | Author | Files | Lines |
|---|
|
[ Upstream commit 5f1ef0dfcb5b7f4a91a9b0e0ba533efd9f7e2cdb ]
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: Leon Chen <leonchen.oss@139.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit d008ba8be8984760e36d7dcd4adbd5a41a645708 upstream.
Some of the sizing logic through tracer_alloc_buffers() uses int
internally, causing unexpected behavior if the user passes a value that
does not fit in an int (on my x86 machine, the result is uselessly tiny
buffers).
Fix by plumbing the parameter's real type (unsigned long) through to the
ring buffer allocation functions, which already use unsigned long.
It has always been possible to create larger ring buffers via the sysfs
interface: this only affects the cmdline parameter.
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://patch.msgid.link/bff42a4288aada08bdf74da3f5b67a2c28b761f8.1772852067.git.calvin@wbinvd.org
Fixes: 73c5162aa362 ("tracing: keep ring buffer to minimum size till used")
Signed-off-by: Calvin Owens <calvin@wbinvd.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
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>
|
|
[ 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>
|
|
commit b042fdf18e89a347177a49e795d8e5184778b5b6 upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
[ Upstream commit cd4453c5e983cf1fd5757e9acb915adb1e4602b6 ]
Syzkaller trigger a fault injection warning:
WARNING: CPU: 1 PID: 12326 at tracepoint_add_func+0xbfc/0xeb0
Modules linked in:
CPU: 1 UID: 0 PID: 12326 Comm: syz.6.10325 Tainted: G U 6.14.0-rc5-syzkaller #0
Tainted: [U]=USER
Hardware name: Google Compute Engine/Google Compute Engine
RIP: 0010:tracepoint_add_func+0xbfc/0xeb0 kernel/tracepoint.c:294
Code: 09 fe ff 90 0f 0b 90 0f b6 74 24 43 31 ff 41 bc ea ff ff ff
RSP: 0018:ffffc9000414fb48 EFLAGS: 00010283
RAX: 00000000000012a1 RBX: ffffffff8e240ae0 RCX: ffffc90014b78000
RDX: 0000000000080000 RSI: ffffffff81bbd78b RDI: 0000000000000001
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: ffffffffffffffef
R13: 0000000000000000 R14: dffffc0000000000 R15: ffffffff81c264f0
FS: 00007f27217f66c0(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2e80dff8 CR3: 00000000268f8000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
tracepoint_probe_register_prio+0xc0/0x110 kernel/tracepoint.c:464
register_trace_prio_sched_switch include/trace/events/sched.h:222 [inline]
register_pid_events kernel/trace/trace_events.c:2354 [inline]
event_pid_write.isra.0+0x439/0x7a0 kernel/trace/trace_events.c:2425
vfs_write+0x24c/0x1150 fs/read_write.c:677
ksys_write+0x12b/0x250 fs/read_write.c:731
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
We can reproduce the warning by following the steps below:
1. echo 8 >> set_event_notrace_pid. Let tr->filtered_pids owns one pid
and register sched_switch tracepoint.
2. echo ' ' >> set_event_pid, and perform fault injection during chunk
allocation of trace_pid_list_alloc. Let pid_list with no pid and
assign to tr->filtered_pids.
3. echo ' ' >> set_event_pid. Let pid_list is NULL and assign to
tr->filtered_pids.
4. echo 9 >> set_event_pid, will trigger the double register
sched_switch tracepoint warning.
The reason is that syzkaller injects a fault into the chunk allocation
in trace_pid_list_alloc, causing a failure in trace_pid_list_set, which
may trigger double register of the same tracepoint. This only occurs
when the system is about to crash, but to suppress this warning, let's
add failure handling logic to trace_pid_list_set.
Link: https://lore.kernel.org/20250908024658.2390398-1-pulehui@huaweicloud.com
Fixes: 8d6e90983ade ("tracing: Create a sparse bitmask for pid filtering")
Reported-by: syzbot+161412ccaeff20ce4dde@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/67cb890e.050a0220.d8275.022e.GAE@google.com
Signed-off-by: Pu Lehui <pulehui@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
|
|
[ Upstream commit 3d62ab32df065e4a7797204a918f6489ddb8a237 ]
Both tracing_mark_write and tracing_mark_raw_write call
__copy_from_user_inatomic during preempt_disable. But in some case,
__copy_from_user_inatomic may trigger page fault, and will call schedule()
subtly. And if a task is migrated to other cpu, the following warning will
be trigger:
if (RB_WARN_ON(cpu_buffer,
!local_read(&cpu_buffer->committing)))
An example can illustrate this issue:
process flow CPU
---------------------------------------------------------------------
tracing_mark_raw_write(): cpu:0
...
ring_buffer_lock_reserve(): cpu:0
...
cpu = raw_smp_processor_id() cpu:0
cpu_buffer = buffer->buffers[cpu] cpu:0
...
...
__copy_from_user_inatomic(): cpu:0
...
# page fault
do_mem_abort(): cpu:0
...
# Call schedule
schedule() cpu:0
...
# the task schedule to cpu1
__buffer_unlock_commit(): cpu:1
...
ring_buffer_unlock_commit(): cpu:1
...
cpu = raw_smp_processor_id() cpu:1
cpu_buffer = buffer->buffers[cpu] cpu:1
As shown above, the process will acquire cpuid twice and the return values
are not the same.
To fix this problem using copy_from_user_nofault instead of
__copy_from_user_inatomic, as the former performs 'access_ok' before
copying.
Link: https://lore.kernel.org/20250819105152.2766363-1-luogengkun@huaweicloud.com
Fixes: 656c7f0d2d2b ("tracing: Replace kmap with copy_from_user() in trace_marker writing")
Signed-off-by: Luo Gengkun <luogengkun@huaweicloud.com>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
|
|
[ Upstream commit 4013aef2ced9b756a410f50d12df9ebe6a883e4a ]
When calling ftrace_dump_one() concurrently with reading trace_pipe,
a WARN_ON_ONCE() in trace_printk_seq() can be triggered due to a race
condition.
The issue occurs because:
CPU0 (ftrace_dump) CPU1 (reader)
echo z > /proc/sysrq-trigger
!trace_empty(&iter)
trace_iterator_reset(&iter) <- len = size = 0
cat /sys/kernel/tracing/trace_pipe
trace_find_next_entry_inc(&iter)
__find_next_entry
ring_buffer_empty_cpu <- all empty
return NULL
trace_printk_seq(&iter.seq)
WARN_ON_ONCE(s->seq.len >= s->seq.size)
In the context between trace_empty() and trace_find_next_entry_inc()
during ftrace_dump, the ring buffer data was consumed by other readers.
This caused trace_find_next_entry_inc to return NULL, failing to populate
`iter.seq`. At this point, due to the prior trace_iterator_reset, both
`iter.seq.len` and `iter.seq.size` were set to 0. Since they are equal,
the WARN_ON_ONCE condition is triggered.
Move the trace_printk_seq() into the if block that checks to make sure the
return value of trace_find_next_entry_inc() is non-NULL in
ftrace_dump_one(), ensuring the 'iter.seq' is properly populated before
subsequent operations.
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Ingo Molnar <mingo@elte.hu>
Link: https://lore.kernel.org/20250822033343.3000289-1-wutengda@huaweicloud.com
Fixes: d769041f8653 ("ring_buffer: implement new locking")
Signed-off-by: Tengda Wu <wutengda@huaweicloud.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
|
|
[ Upstream commit 6a909ea83f226803ea0e718f6e88613df9234d58 ]
When the length of the string written to set_ftrace_filter exceeds
FTRACE_BUFF_MAX, the following KASAN alarm will be triggered:
BUG: KASAN: slab-out-of-bounds in strsep+0x18c/0x1b0
Read of size 1 at addr ffff0000d00bd5ba by task ash/165
CPU: 1 UID: 0 PID: 165 Comm: ash Not tainted 6.16.0-g6bcdbd62bd56-dirty
Hardware name: linux,dummy-virt (DT)
Call trace:
show_stack+0x34/0x50 (C)
dump_stack_lvl+0xa0/0x158
print_address_description.constprop.0+0x88/0x398
print_report+0xb0/0x280
kasan_report+0xa4/0xf0
__asan_report_load1_noabort+0x20/0x30
strsep+0x18c/0x1b0
ftrace_process_regex.isra.0+0x100/0x2d8
ftrace_regex_release+0x484/0x618
__fput+0x364/0xa58
____fput+0x28/0x40
task_work_run+0x154/0x278
do_notify_resume+0x1f0/0x220
el0_svc+0xec/0xf0
el0t_64_sync_handler+0xa0/0xe8
el0t_64_sync+0x1ac/0x1b0
The reason is that trace_get_user will fail when processing a string
longer than FTRACE_BUFF_MAX, but not set the end of parser->buffer to 0.
Then an OOB access will be triggered in ftrace_regex_release->
ftrace_process_regex->strsep->strpbrk. We can solve this problem by
limiting access to parser->buffer when trace_get_user failed.
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/20250813040232.1344527-1-pulehui@huaweicloud.com
Fixes: 8c9af478c06b ("ftrace: Handle commands when closing set_ftrace_filter file")
Signed-off-by: Pu Lehui <pulehui@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
[ Upstream commit c89504a703fb779052213add0e8ed642f4a4f1c8 ]
Several places in the trace.c file there's a goto out where the out is
simply a return. There's no reason to jump to the out label if it's not
doing any more logic but simply returning from the function.
Replace the goto outs with a return and remove the out labels.
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/20250801203857.538726745@kernel.org
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Stable-dep-of: 6a909ea83f22 ("tracing: Limit access to parser->buffer when trace_get_user failed")
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
[ Upstream commit 119a5d573622ae90ba730d18acfae9bb75d77b9a ]
When the ring buffer was first introduced, reading the non-consuming
"trace" file required disabling the writing of the ring buffer. To make
sure the writing was fully disabled before iterating the buffer with a
non-consuming read, it would set the disable flag of the buffer and then
call an RCU synchronization to make sure all the buffers were
synchronized.
The function ring_buffer_read_start() originally would initialize the
iterator and call an RCU synchronization, but this was for each individual
per CPU buffer where this would get called many times on a machine with
many CPUs before the trace file could be read. The commit 72c9ddfd4c5bf
("ring-buffer: Make non-consuming read less expensive with lots of cpus.")
separated ring_buffer_read_start into ring_buffer_read_prepare(),
ring_buffer_read_sync() and then ring_buffer_read_start() to allow each of
the per CPU buffers to be prepared, call the read_buffer_read_sync() once,
and then the ring_buffer_read_start() for each of the CPUs which made
things much faster.
The commit 1039221cc278 ("ring-buffer: Do not disable recording when there
is an iterator") removed the requirement of disabling the recording of the
ring buffer in order to iterate it, but it did not remove the
synchronization that was happening that was required to wait for all the
buffers to have no more writers. It's now OK for the buffers to have
writers and no synchronization is needed.
Remove the synchronization and put back the interface for the ring buffer
iterator back before commit 72c9ddfd4c5bf was applied.
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/20250630180440.3eabb514@batman.local.home
Reported-by: David Howells <dhowells@redhat.com>
Fixes: 1039221cc278 ("ring-buffer: Do not disable recording when there is an iterator")
Tested-by: David Howells <dhowells@redhat.com>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
|
|
commit 2fbdb6d8e03b70668c0876e635506540ae92ab05 upstream.
On arm32, size_t is defined to be unsigned int, while PAGE_SIZE is
unsigned long. This hence triggers a compilation warning as min()
asserts the type of two operands to be equal. Casting PAGE_SIZE to size_t
solves this issue and works on other target architectures as well.
Compilation warning details:
kernel/trace/trace.c: In function 'tracing_splice_read_pipe':
./include/linux/minmax.h:20:28: warning: comparison of distinct pointer types lacks a cast
(!!(sizeof((typeof(x) *)1 == (typeof(y) *)1)))
^
./include/linux/minmax.h:26:4: note: in expansion of macro '__typecheck'
(__typecheck(x, y) && __no_side_effects(x, y))
^~~~~~~~~~~
...
kernel/trace/trace.c:6771:8: note: in expansion of macro 'min'
min((size_t)trace_seq_used(&iter->seq),
^~~
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/20250526013731.1198030-1-pantaixi@huaweicloud.com
Fixes: f5178c41bb43 ("tracing: Fix oob write in trace_seq_to_buffer()")
Reviewed-by: Jeongjun Park <aha310510@gmail.com>
Signed-off-by: Pan Taixi <pantaixi@huaweicloud.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
[ Upstream commit 196a062641fe68d9bfe0ad36b6cd7628c99ad22c ]
Binary printing functions are using printf() type of format, and compiler
is not happy about them as is:
kernel/trace/trace.c:3292:9: error: function ‘trace_vbprintk’ might be a candidate for ‘gnu_printf’ format attribute [-Werror=suggest-attribute=format]
kernel/trace/trace_seq.c:182:9: error: function ‘trace_seq_bprintf’ might be a candidate for ‘gnu_printf’ format attribute [-Werror=suggest-attribute=format]
Fix the compilation errors by adding __printf() attribute.
While at it, move existing __printf() attributes from the implementations
to the declarations. IT also fixes incorrect attribute parameters that are
used for trace_array_printk().
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Kees Cook <kees@kernel.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20250321144822.324050-4-andriy.shevchenko@linux.intel.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
|
|
commit f5178c41bb43444a6008150fe6094497135d07cb upstream.
syzbot reported this bug:
==================================================================
BUG: KASAN: slab-out-of-bounds in trace_seq_to_buffer kernel/trace/trace.c:1830 [inline]
BUG: KASAN: slab-out-of-bounds in tracing_splice_read_pipe+0x6be/0xdd0 kernel/trace/trace.c:6822
Write of size 4507 at addr ffff888032b6b000 by task syz.2.320/7260
CPU: 1 UID: 0 PID: 7260 Comm: syz.2.320 Not tainted 6.15.0-rc1-syzkaller-00301-g3bde70a2c827 #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:408 [inline]
print_report+0xc3/0x670 mm/kasan/report.c:521
kasan_report+0xe0/0x110 mm/kasan/report.c:634
check_region_inline mm/kasan/generic.c:183 [inline]
kasan_check_range+0xef/0x1a0 mm/kasan/generic.c:189
__asan_memcpy+0x3c/0x60 mm/kasan/shadow.c:106
trace_seq_to_buffer kernel/trace/trace.c:1830 [inline]
tracing_splice_read_pipe+0x6be/0xdd0 kernel/trace/trace.c:6822
....
==================================================================
It has been reported that trace_seq_to_buffer() tries to copy more data
than PAGE_SIZE to buf. Therefore, to prevent this, we should use the
smaller of trace_seq_used(&iter->seq) and PAGE_SIZE as an argument.
Link: https://lore.kernel.org/20250422113026.13308-1-aha310510@gmail.com
Reported-by: syzbot+c8cd2d2c412b868263fb@syzkaller.appspotmail.com
Fixes: 3c56819b14b0 ("tracing: splice support for tracing_pipe")
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Jeongjun Park <aha310510@gmail.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit 22bec11a569983f39c6061cb82279e7de9e3bdfc upstream.
When the function tracing_set_tracer() switched over to using the guard()
infrastructure, it did not need to save the 'ret' variable and would just
return the value when an error arised, instead of setting ret and jumping
to an out label.
When CONFIG_TRACER_SNAPSHOT is enabled, it had code that expected the
"ret" variable to be initialized to zero and had set 'ret' while holding
an arch_spin_lock() (not used by guard), and then upon releasing the lock
it would check 'ret' and exit if set. But because ret was only set when an
error occurred while holding the locks, 'ret' would be used uninitialized
if there was no error. The code in the CONFIG_TRACER_SNAPSHOT block should
be self contain. Make sure 'ret' is also set when no error occurred.
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/20250106111143.2f90ff65@gandalf.local.home
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/r/202412271654.nJVBuwmF-lkp@intel.com/
Fixes: d33b10c0c73ad ("tracing: Switch trace.c code over to use guard()")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
[ Upstream commit 60b8f711143de7cd9c0f55be0fe7eb94b19eb5c7 ]
Currently if __tracing_resize_ring_buffer() returns an error, the
tracing_resize_ringbuffer() returns -ENOMEM. But it may not be a memory
issue that caused the function to fail. If the ring buffer is memory
mapped, then the resizing of the ring buffer will be disabled. But if the
user tries to resize the buffer, it will get an -ENOMEM returned, which is
confusing because there is plenty of memory. The actual error returned was
-EBUSY, which would make much more sense to the user.
Cc: stable@vger.kernel.org
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Vincent Donnefort <vdonnefort@google.com>
Link: https://lore.kernel.org/20250213134132.7e4505d7@gandalf.local.home
Fixes: 117c39200d9d7 ("ring-buffer: Introducing ring-buffer mapping functions")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
|
|
[ Upstream commit d33b10c0c73adca00f72bf4a153a07b7f5f34715 ]
There are several functions in trace.c that have "goto out;" or
equivalent on error in order to release locks or free values that were
allocated. This can be error prone or just simply make the code more
complex.
Switch every location that ends with unlocking a mutex or freeing on error
over to using the guard(mutex)() and __free() infrastructure to let the
compiler worry about releasing locks. This makes the code easier to read
and understand.
There's one place that should probably return an error but instead return
0. This does not change the return as the only changes are to do the
conversion without changing the logic. Fixing that location will have to
come later.
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Link: https://lore.kernel.org/20241224221413.7b8c68c3@batman.local.home
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Stable-dep-of: 60b8f711143d ("tracing: Have the error of __tracing_resize_ring_buffer() passed to user")
Signed-off-by: Sasha Levin <sashal@kernel.org>
|
|
commit 129fe718819cc5e24ea2f489db9ccd4371f0c6f6 upstream.
When trying to mmap a trace instance buffer that is attached to
reserve_mem, it would crash:
BUG: unable to handle page fault for address: ffffe97bd00025c8
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 2862f3067 P4D 2862f3067 PUD 0
Oops: Oops: 0000 [#1] PREEMPT_RT SMP PTI
CPU: 4 UID: 0 PID: 981 Comm: mmap-rb Not tainted 6.14.0-rc2-test-00003-g7f1a5e3fbf9e-dirty #233
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:validate_page_before_insert+0x5/0xb0
Code: e2 01 89 d0 c3 cc cc cc cc 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 44 00 00 <48> 8b 46 08 a8 01 75 67 66 90 48 89 f0 8b 50 34 85 d2 74 76 48 89
RSP: 0018:ffffb148c2f3f968 EFLAGS: 00010246
RAX: ffff9fa5d3322000 RBX: ffff9fa5ccff9c08 RCX: 00000000b879ed29
RDX: ffffe97bd00025c0 RSI: ffffe97bd00025c0 RDI: ffff9fa5ccff9c08
RBP: ffffb148c2f3f9f0 R08: 0000000000000004 R09: 0000000000000004
R10: 0000000000000000 R11: 0000000000000200 R12: 0000000000000000
R13: 00007f16a18d5000 R14: ffff9fa5c48db6a8 R15: 0000000000000000
FS: 00007f16a1b54740(0000) GS:ffff9fa73df00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffe97bd00025c8 CR3: 00000001048c6006 CR4: 0000000000172ef0
Call Trace:
<TASK>
? __die_body.cold+0x19/0x1f
? __die+0x2e/0x40
? page_fault_oops+0x157/0x2b0
? search_module_extables+0x53/0x80
? validate_page_before_insert+0x5/0xb0
? kernelmode_fixup_or_oops.isra.0+0x5f/0x70
? __bad_area_nosemaphore+0x16e/0x1b0
? bad_area_nosemaphore+0x16/0x20
? do_kern_addr_fault+0x77/0x90
? exc_page_fault+0x22b/0x230
? asm_exc_page_fault+0x2b/0x30
? validate_page_before_insert+0x5/0xb0
? vm_insert_pages+0x151/0x400
__rb_map_vma+0x21f/0x3f0
ring_buffer_map+0x21b/0x2f0
tracing_buffers_mmap+0x70/0xd0
__mmap_region+0x6f0/0xbd0
mmap_region+0x7f/0x130
do_mmap+0x475/0x610
vm_mmap_pgoff+0xf2/0x1d0
ksys_mmap_pgoff+0x166/0x200
__x64_sys_mmap+0x37/0x50
x64_sys_call+0x1670/0x1d70
do_syscall_64+0xbb/0x1d0
entry_SYSCALL_64_after_hwframe+0x77/0x7f
The reason was that the code that maps the ring buffer pages to user space
has:
page = virt_to_page((void *)cpu_buffer->subbuf_ids[s]);
And uses that in:
vm_insert_pages(vma, vma->vm_start, pages, &nr_pages);
But virt_to_page() does not work with vmap()'d memory which is what the
persistent ring buffer has. It is rather trivial to allow this, but for
now just disable mmap() of instances that have their ring buffer from the
reserve_mem option.
If an mmap() is performed on a persistent buffer it will return -ENODEV
just like it would if the .mmap field wasn't defined in the
file_operations structure.
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Vincent Donnefort <vdonnefort@google.com>
Link: https://lore.kernel.org/20250214115547.0d7287d3@gandalf.local.home
Fixes: 9b7bdf6f6ece6 ("tracing: Have trace_printk not use binary prints if boot buffer")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit 98feccbf32cfdde8c722bc4587aaa60ee5ac33f0 upstream.
If a large count is provided, it will trigger a warning in bitmap_parse_user.
Also check zero for it.
Cc: stable@vger.kernel.org
Fixes: 9e01c1b74c953 ("cpumask: convert kernel trace functions")
Link: https://lore.kernel.org/20241216073238.2573704-1-lizhi.xu@windriver.com
Reported-by: syzbot+0aecfd34fb878546f3fd@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=0aecfd34fb878546f3fd
Tested-by: syzbot+0aecfd34fb878546f3fd@syzkaller.appspotmail.com
Signed-off-by: Lizhi Xu <lizhi.xu@windriver.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit afd2627f727b89496d79a6b934a025fc916d4ded upstream.
The TP_printk() portion of a trace event is executed at the time a event
is read from the trace. This can happen seconds, minutes, hours, days,
months, years possibly later since the event was recorded. If the print
format contains a dereference to a string via "%s", and that string was
allocated, there's a chance that string could be freed before it is read
by the trace file.
To protect against such bugs, there are two functions that verify the
event. The first one is test_event_printk(), which is called when the
event is created. It reads the TP_printk() format as well as its arguments
to make sure nothing may be dereferencing a pointer that was not copied
into the ring buffer along with the event. If it is, it will trigger a
WARN_ON().
For strings that use "%s", it is not so easy. The string may not reside in
the ring buffer but may still be valid. Strings that are static and part
of the kernel proper which will not be freed for the life of the running
system, are safe to dereference. But to know if it is a pointer to a
static string or to something on the heap can not be determined until the
event is triggered.
This brings us to the second function that tests for the bad dereferencing
of strings, trace_check_vprintf(). It would walk through the printf format
looking for "%s", and when it finds it, it would validate that the pointer
is safe to read. If not, it would produces a WARN_ON() as well and write
into the ring buffer "[UNSAFE-MEMORY]".
The problem with this is how it used va_list to have vsnprintf() handle
all the cases that it didn't need to check. Instead of re-implementing
vsnprintf(), it would make a copy of the format up to the %s part, and
call vsnprintf() with the current va_list ap variable, where the ap would
then be ready to point at the string in question.
For architectures that passed va_list by reference this was possible. For
architectures that passed it by copy it was not. A test_can_verify()
function was used to differentiate between the two, and if it wasn't
possible, it would disable it.
Even for architectures where this was feasible, it was a stretch to rely
on such a method that is undocumented, and could cause issues later on
with new optimizations of the compiler.
Instead, the first function test_event_printk() was updated to look at
"%s" as well. If the "%s" argument is a pointer outside the event in the
ring buffer, it would find the field type of the event that is the problem
and mark the structure with a new flag called "needs_test". The event
itself will be marked by TRACE_EVENT_FL_TEST_STR to let it be known that
this event has a field that needs to be verified before the event can be
printed using the printf format.
When the event fields are created from the field type structure, the
fields would copy the field type's "needs_test" value.
Finally, before being printed, a new function ignore_event() is called
which will check if the event has the TEST_STR flag set (if not, it
returns false). If the flag is set, it then iterates through the events
fields looking for the ones that have the "needs_test" flag set.
Then it uses the offset field from the field structure to find the pointer
in the ring buffer event. It runs the tests to make sure that pointer is
safe to print and if not, it triggers the WARN_ON() and also adds to the
trace output that the event in question has an unsafe memory access.
The ignore_event() makes the trace_check_vprintf() obsolete so it is
removed.
Link: https://lore.kernel.org/all/CAHk-=wh3uOnqnZPpR0PeLZZtyWbZLboZ7cHLCKRWsocvs9Y7hQ@mail.gmail.com/
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>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/20241217024720.848621576@goodmis.org
Fixes: 5013f454a352c ("tracing: Add check of trace event print fmts for dereferencing pointers")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit 8cd63406d08110c8098e1efda8aef7ddab4db348 upstream.
The TP_printk() of a TRACE_EVENT() is a generic printf format that any
developer can create for their event. It may include pointers to strings
and such. A boot mapped buffer may contain data from a previous kernel
where the strings addresses are different.
One solution is to copy the event content and update the pointers by the
recorded delta, but a simpler solution (for now) is to just use the
print_fields() function to print these events. The print_fields() function
just iterates the fields and prints them according to what type they are,
and ignores the TP_printk() format from the event itself.
To understand the difference, when printing via TP_printk() the output
looks like this:
4582.696626: kmem_cache_alloc: call_site=getname_flags+0x47/0x1f0 ptr=00000000e70e10e0 bytes_req=4096 bytes_alloc=4096 gfp_flags=GFP_KERNEL node=-1 accounted=false
4582.696629: kmem_cache_alloc: call_site=alloc_empty_file+0x6b/0x110 ptr=0000000095808002 bytes_req=360 bytes_alloc=384 gfp_flags=GFP_KERNEL node=-1 accounted=false
4582.696630: kmem_cache_alloc: call_site=security_file_alloc+0x24/0x100 ptr=00000000576339c3 bytes_req=16 bytes_alloc=16 gfp_flags=GFP_KERNEL|__GFP_ZERO node=-1 accounted=false
4582.696653: kmem_cache_free: call_site=do_sys_openat2+0xa7/0xd0 ptr=00000000e70e10e0 name=names_cache
But when printing via print_fields() (echo 1 > /sys/kernel/tracing/options/fields)
the same event output looks like this:
4582.696626: kmem_cache_alloc: call_site=0xffffffff92d10d97 (-1831793257) ptr=0xffff9e0e8571e000 (-107689771147264) bytes_req=0x1000 (4096) bytes_alloc=0x1000 (4096) gfp_flags=0xcc0 (3264) node=0xffffffff (-1) accounted=(0)
4582.696629: kmem_cache_alloc: call_site=0xffffffff92d0250b (-1831852789) ptr=0xffff9e0e8577f800 (-107689770747904) bytes_req=0x168 (360) bytes_alloc=0x180 (384) gfp_flags=0xcc0 (3264) node=0xffffffff (-1) accounted=(0)
4582.696630: kmem_cache_alloc: call_site=0xffffffff92efca74 (-1829778828) ptr=0xffff9e0e8d35d3b0 (-107689640864848) bytes_req=0x10 (16) bytes_alloc=0x10 (16) gfp_flags=0xdc0 (3520) node=0xffffffff (-1) accounted=(0)
4582.696653: kmem_cache_free: call_site=0xffffffff92cfbea7 (-1831879001) ptr=0xffff9e0e8571e000 (-107689771147264) name=names_cache
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/20241218141507.28389a1d@gandalf.local.home
Fixes: 07714b4bb3f98 ("tracing: Handle old buffer mappings for event strings and functions")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
[ Upstream commit 6ce5a6f0a07d37cc377df08a8d8a9c283420f323 ]
The issue that unrelated function name is shown on stack trace like
following even though it should be trampoline code address is caused by
the creation of trampoline code in the area where .init.text section
of module was freed after module is loaded.
bash-1344 [002] ..... 43.644608: <stack trace>
=> (MODULE INIT FUNCTION)
=> vfs_write
=> ksys_write
=> do_syscall_64
=> entry_SYSCALL_64_after_hwframe
To resolve this, when function address of stack trace entry is in
trampoline, output without looking up symbol name.
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/20241021071454.34610-2-tatsuya.s2862@gmail.com
Signed-off-by: Tatsuya S <tatsuya.s2862@gmail.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>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull ring buffer fixes from Steven Rostedt:
- Revert: "ring-buffer: Do not have boot mapped buffers hook to CPU
hotplug"
A crash that happened on cpu hotplug was actually caused by the
incorrect ref counting that was fixed by commit 2cf9733891a4
("ring-buffer: Fix refcount setting of boot mapped buffers"). The
removal of calling cpu hotplug callbacks on memory mapped buffers was
not an issue even though the tests at the time pointed toward it. But
in fact, there's a check in that code that tests to see if the
buffers are already allocated or not, and will not allocate them
again if they are. Not calling the cpu hotplug callbacks ended up not
initializing the non boot CPU buffers.
Simply remove that change.
- Clear all CPU buffers when starting tracing in a boot mapped buffer
To properly process events from a previous boot, the address space
needs to be accounted for due to KASLR and the events in the buffer
are updated accordingly when read. This also requires that when the
buffer has tracing enabled again in the current boot that the buffers
are reset so that events from the previous boot do not interact with
the events of the current boot and cause confusing due to not having
the proper meta data.
It was found that if a CPU is taken offline, that its per CPU buffer
is not reset when tracing starts. This allows for events to be from
both the previous boot and the current boot to be in the buffer at
the same time. Clear all CPU buffers when tracing is started in a
boot mapped buffer.
* tag 'trace-ringbuffer-v6.12-rc7-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
tracing/ring-buffer: Clear all memory mapped CPU ring buffers on first recording
Revert: "ring-buffer: Do not have boot mapped buffers hook to CPU hotplug"
|
|
The events of a memory mapped ring buffer from the previous boot should
not be mixed in with events from the current boot. There's meta data that
is used to handle KASLR so that function names can be shown properly.
Also, since the timestamps of the previous boot have no meaning to the
timestamps of the current boot, having them intermingled in a buffer can
also cause confusion because there could possibly be events in the future.
When a trace is activated the meta data is reset so that the pointers of
are now processed for the new address space. The trace buffers are reset
when tracing starts for the first time. The problem here is that the reset
only happens on online CPUs. If a CPU is offline, it does not get reset.
To demonstrate the issue, a previous boot had tracing enabled in the boot
mapped ring buffer on reboot. On the following boot, tracing has not been
started yet so the function trace from the previous boot is still visible.
# trace-cmd show -B boot_mapped -c 3 | tail
<idle>-0 [003] d.h2. 156.462395: __rcu_read_lock <-cpu_emergency_disable_virtualization
<idle>-0 [003] d.h2. 156.462396: vmx_emergency_disable_virtualization_cpu <-cpu_emergency_disable_virtualization
<idle>-0 [003] d.h2. 156.462396: __rcu_read_unlock <-__sysvec_reboot
<idle>-0 [003] d.h2. 156.462397: stop_this_cpu <-__sysvec_reboot
<idle>-0 [003] d.h2. 156.462397: set_cpu_online <-stop_this_cpu
<idle>-0 [003] d.h2. 156.462397: disable_local_APIC <-stop_this_cpu
<idle>-0 [003] d.h2. 156.462398: clear_local_APIC <-disable_local_APIC
<idle>-0 [003] d.h2. 156.462574: mcheck_cpu_clear <-stop_this_cpu
<idle>-0 [003] d.h2. 156.462575: mce_intel_feature_clear <-stop_this_cpu
<idle>-0 [003] d.h2. 156.462575: lmce_supported <-mce_intel_feature_clear
Now, if CPU 3 is taken offline, and tracing is started on the memory
mapped ring buffer, the events from the previous boot in the CPU 3 ring
buffer is not reset. Now those events are using the meta data from the
current boot and produces just hex values.
# echo 0 > /sys/devices/system/cpu/cpu3/online
# trace-cmd start -B boot_mapped -p function
# trace-cmd show -B boot_mapped -c 3 | tail
<idle>-0 [003] d.h2. 156.462395: 0xffffffff9a1e3194 <-0xffffffff9a0f655e
<idle>-0 [003] d.h2. 156.462396: 0xffffffff9a0a1d24 <-0xffffffff9a0f656f
<idle>-0 [003] d.h2. 156.462396: 0xffffffff9a1e6bc4 <-0xffffffff9a0f7323
<idle>-0 [003] d.h2. 156.462397: 0xffffffff9a0d12b4 <-0xffffffff9a0f732a
<idle>-0 [003] d.h2. 156.462397: 0xffffffff9a1458d4 <-0xffffffff9a0d12e2
<idle>-0 [003] d.h2. 156.462397: 0xffffffff9a0faed4 <-0xffffffff9a0d12e7
<idle>-0 [003] d.h2. 156.462398: 0xffffffff9a0faaf4 <-0xffffffff9a0faef2
<idle>-0 [003] d.h2. 156.462574: 0xffffffff9a0e3444 <-0xffffffff9a0d12ef
<idle>-0 [003] d.h2. 156.462575: 0xffffffff9a0e4964 <-0xffffffff9a0d12ef
<idle>-0 [003] d.h2. 156.462575: 0xffffffff9a0e3fb0 <-0xffffffff9a0e496f
Reset all CPUs when starting a boot mapped ring buffer for the first time,
and not just the online CPUs.
Fixes: 7a1d1e4b9639f ("tracing/ring-buffer: Add last_boot_info file to boot instance")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
|
|
Commit ee7f3666995d ("tracefs: Have new files inherit the ownership of
their parent") and commit 48b27b6b5191 ("tracefs: Set all files to the
same group ownership as the mount option") introduced a new gid mount
option that allows specifying a group to apply to all entries in tracefs.
Document this in the tracing readme.
Cc: Eric Sandeen <sandeen@redhat.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Ali Zahraee <ahzahraee@gmail.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Link: https://lore.kernel.org/20241030171928.4168869-3-kaleshsingh@google.com
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
|
|
A ring buffer which has its buffered mapped at boot up to fixed memory
should not be freed. Other buffers can be. The ref counting setup was
wrong for both. It made the not mapped buffers ref count have zero, and the
boot mapped buffer a ref count of 1. But an normally allocated buffer
should be 1, where it can be removed.
Keep the ref count of a normal boot buffer with its setup ref count (do
not decrement it), and increment the fixed memory boot mapped buffer's ref
count.
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/20241011165224.33dd2624@gandalf.local.home
Fixes: e645535a954ad ("tracing: Add option to use memmapped memory for trace boot instance")
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
|
|
When the tp_printk kernel command line is used, the trace events go
directly to printk(). It is still checked via the trace_check_vprintf()
function to make sure the pointers of the trace event are legit.
The addition of reading buffers from previous boots required adding a
delta between the addresses of the previous boot and the current boot so
that the pointers in the old buffer can still be used. But this required
adding a trace_array pointer to acquire the delta offsets.
The tp_printk code does not provide a trace_array (tr) pointer, so when
the offsets were examined, a NULL pointer dereference happened and the
kernel crashed.
If the trace_array does not exist, just default the delta offsets to zero,
as that also means the trace event is not being read from a previous boot.
Link: https://lore.kernel.org/all/Zv3z5UsG_jsO9_Tb@aschofie-mobl2.lan/
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/20241003104925.4e1b1fd9@gandalf.local.home
Fixes: 07714b4bb3f98 ("tracing: Handle old buffer mappings for event strings and functions")
Reported-by: Alison Schofield <alison.schofield@intel.com>
Tested-by: Alison Schofield <alison.schofield@intel.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
|
|
no_llseek had been defined to NULL two years ago, in commit 868941b14441
("fs: remove no_llseek")
To quote that commit,
At -rc1 we'll need do a mechanical removal of no_llseek -
git grep -l -w no_llseek | grep -v porting.rst | while read i; do
sed -i '/\<no_llseek\>/d' $i
done
would do it.
Unfortunately, that hadn't been done. Linus, could you do that now, so
that we could finally put that thing to rest? All instances are of the
form
.llseek = no_llseek,
so it's obviously safe.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
