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commit 67ab5eb71b37b55f7c5522d080a1b42823351776 upstream.
tr->n_err_log_entries should only be increased if entry allocation
succeeds.
Doing it when it fails won't cause any problems other than wasting an
entry, but should be fixed anyway.
Link: https://lkml.kernel.org/r/cad1ab28f75968db0f466925e7cba5970cec6c29.1643319703.git.zanussi@kernel.org
Cc: stable@vger.kernel.org
Fixes: 2f754e771b1a6 ("tracing: Don't inc err_log entry count if entry allocation fails")
Signed-off-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit e629e7b525a179e29d53463d992bdee759c950fb upstream.
kfree() is missing on an error path to free the memory allocated by
kstrdup():
p = param = kstrdup(data->params[i], GFP_KERNEL);
So it is better to free it via kfree(p).
Link: https://lkml.kernel.org/r/tencent_C52895FD37802832A3E5B272D05008866F0A@qq.com
Cc: stable@vger.kernel.org
Fixes: d380dcde9a07c ("tracing: Fix now invalid var_ref_vals assumption in trace action")
Signed-off-by: Xiaoke Wang <xkernel.wang@foxmail.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit dfea08a2116fe327f79d8f4d4b2cf6e0c88be11f upstream.
The 'nmissed' column of the 'kprobe_profile' file for kretprobe is
not showed correctly, kretprobe can be skipped by two reasons,
shortage of kretprobe_instance which is counted by tk->rp.nmissed,
and kprobe itself is missed by some reason, so to show the sum.
Link: https://lkml.kernel.org/r/20220107150242.5019-1-xyz.sun.ok@gmail.com
Cc: stable@vger.kernel.org
Fixes: 4a846b443b4e ("tracing/kprobes: Cleanup kprobe tracer code")
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Xiangyang Zhang <xyz.sun.ok@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit db52f57211b4e45f0ebb274e2c877b211dc18591 ]
Branch data available to BPF programs can be very useful to get stack traces
out of userspace application.
Commit fff7b64355ea ("bpf: Add bpf_read_branch_records() helper") added BPF
support to capture branch records in x86. Enable this feature also for other
architectures as well by removing checks specific to x86.
If an architecture doesn't support branch records, bpf_read_branch_records()
still has appropriate checks and it will return an -EINVAL in that scenario.
Based on UAPI helper doc in include/uapi/linux/bpf.h, unsupported architectures
should return -ENOENT in such case. Hence, update the appropriate check to
return -ENOENT instead.
Selftest 'perf_branches' result on power9 machine which has the branch stacks
support:
- Before this patch:
[command]# ./test_progs -t perf_branches
#88/1 perf_branches/perf_branches_hw:FAIL
#88/2 perf_branches/perf_branches_no_hw:OK
#88 perf_branches:FAIL
Summary: 0/1 PASSED, 0 SKIPPED, 1 FAILED
- After this patch:
[command]# ./test_progs -t perf_branches
#88/1 perf_branches/perf_branches_hw:OK
#88/2 perf_branches/perf_branches_no_hw:OK
#88 perf_branches:OK
Summary: 1/2 PASSED, 0 SKIPPED, 0 FAILED
Selftest 'perf_branches' result on power9 machine which doesn't have branch
stack report:
- After this patch:
[command]# ./test_progs -t perf_branches
#88/1 perf_branches/perf_branches_hw:SKIP
#88/2 perf_branches/perf_branches_no_hw:OK
#88 perf_branches:OK
Summary: 1/1 PASSED, 1 SKIPPED, 0 FAILED
Fixes: fff7b64355eac ("bpf: Add bpf_read_branch_records() helper")
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Kajol Jain <kjain@linux.ibm.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20211206073315.77432-1-kjain@linux.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit f28439db470cca8b6b082239314e9fd10bd39034 upstream.
Tag trace_percpu_buffer as a percpu pointer to resolve warnings
reported by sparse:
/linux/kernel/trace/trace.c:3218:46: warning: incorrect type in initializer (different address spaces)
/linux/kernel/trace/trace.c:3218:46: expected void const [noderef] __percpu *__vpp_verify
/linux/kernel/trace/trace.c:3218:46: got struct trace_buffer_struct *
/linux/kernel/trace/trace.c:3234:9: warning: incorrect type in initializer (different address spaces)
/linux/kernel/trace/trace.c:3234:9: expected void const [noderef] __percpu *__vpp_verify
/linux/kernel/trace/trace.c:3234:9: got int *
Link: https://lkml.kernel.org/r/ebabd3f23101d89cb75671b68b6f819f5edc830b.1640255304.git.naveen.n.rao@linux.vnet.ibm.com
Cc: stable@vger.kernel.org
Reported-by: kernel test robot <lkp@intel.com>
Fixes: 07d777fe8c398 ("tracing: Add percpu buffers for trace_printk()")
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 823e670f7ed616d0ce993075c8afe0217885f79d upstream.
With the new osnoise tracer, we are seeing the below splat:
Kernel attempted to read user page (c7d880000) - exploit attempt? (uid: 0)
BUG: Unable to handle kernel data access on read at 0xc7d880000
Faulting instruction address: 0xc0000000002ffa10
Oops: Kernel access of bad area, sig: 11 [#1]
LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=2048 NUMA pSeries
...
NIP [c0000000002ffa10] __trace_array_vprintk.part.0+0x70/0x2f0
LR [c0000000002ff9fc] __trace_array_vprintk.part.0+0x5c/0x2f0
Call Trace:
[c0000008bdd73b80] [c0000000001c49cc] put_prev_task_fair+0x3c/0x60 (unreliable)
[c0000008bdd73be0] [c000000000301430] trace_array_printk_buf+0x70/0x90
[c0000008bdd73c00] [c0000000003178b0] trace_sched_switch_callback+0x250/0x290
[c0000008bdd73c90] [c000000000e70d60] __schedule+0x410/0x710
[c0000008bdd73d40] [c000000000e710c0] schedule+0x60/0x130
[c0000008bdd73d70] [c000000000030614] interrupt_exit_user_prepare_main+0x264/0x270
[c0000008bdd73de0] [c000000000030a70] syscall_exit_prepare+0x150/0x180
[c0000008bdd73e10] [c00000000000c174] system_call_vectored_common+0xf4/0x278
osnoise tracer on ppc64le is triggering osnoise_taint() for negative
duration in get_int_safe_duration() called from
trace_sched_switch_callback()->thread_exit().
The problem though is that the check for a valid trace_percpu_buffer is
incorrect in get_trace_buf(). The check is being done after calculating
the pointer for the current cpu, rather than on the main percpu pointer.
Fix the check to be against trace_percpu_buffer.
Link: https://lkml.kernel.org/r/a920e4272e0b0635cf20c444707cbce1b2c8973d.1640255304.git.naveen.n.rao@linux.vnet.ibm.com
Cc: stable@vger.kernel.org
Fixes: e2ace001176dc9 ("tracing: Choose static tp_printk buffer by explicit nesting count")
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit f25667e5980a4333729cac3101e5de1bb851f71a ]
Doing the command:
echo 'hist:key=common_pid.execname,common_timestamp' > /sys/kernel/debug/tracing/events/xxx/trigger
Triggers many kmemleak reports:
unreferenced object 0xffff0000c7ea4980 (size 128):
comm "bash", pid 338, jiffies 4294912626 (age 9339.324s)
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<00000000f3469921>] kmem_cache_alloc_trace+0x4c0/0x6f0
[<0000000054ca40c3>] hist_trigger_elt_data_alloc+0x140/0x178
[<00000000633bd154>] tracing_map_init+0x1f8/0x268
[<000000007e814ab9>] event_hist_trigger_func+0xca0/0x1ad0
[<00000000bf8520ed>] trigger_process_regex+0xd4/0x128
[<00000000f549355a>] event_trigger_write+0x7c/0x120
[<00000000b80f898d>] vfs_write+0xc4/0x380
[<00000000823e1055>] ksys_write+0x74/0xf8
[<000000008a9374aa>] __arm64_sys_write+0x24/0x30
[<0000000087124017>] do_el0_svc+0x88/0x1c0
[<00000000efd0dcd1>] el0_svc+0x1c/0x28
[<00000000dbfba9b3>] el0_sync_handler+0x88/0xc0
[<00000000e7399680>] el0_sync+0x148/0x180
unreferenced object 0xffff0000c7ea4980 (size 128):
comm "bash", pid 338, jiffies 4294912626 (age 9339.324s)
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<00000000f3469921>] kmem_cache_alloc_trace+0x4c0/0x6f0
[<0000000054ca40c3>] hist_trigger_elt_data_alloc+0x140/0x178
[<00000000633bd154>] tracing_map_init+0x1f8/0x268
[<000000007e814ab9>] event_hist_trigger_func+0xca0/0x1ad0
[<00000000bf8520ed>] trigger_process_regex+0xd4/0x128
[<00000000f549355a>] event_trigger_write+0x7c/0x120
[<00000000b80f898d>] vfs_write+0xc4/0x380
[<00000000823e1055>] ksys_write+0x74/0xf8
[<000000008a9374aa>] __arm64_sys_write+0x24/0x30
[<0000000087124017>] do_el0_svc+0x88/0x1c0
[<00000000efd0dcd1>] el0_svc+0x1c/0x28
[<00000000dbfba9b3>] el0_sync_handler+0x88/0xc0
[<00000000e7399680>] el0_sync+0x148/0x180
The reason is elts->pages[i] is alloced by get_zeroed_page.
and kmemleak will not scan the area alloced by get_zeroed_page.
The address stored in elts->pages will be regarded as leaked.
That is, the elts->pages[i] will have pointers loaded onto it as well, and
without telling kmemleak about it, those pointers will look like memory
without a reference.
To fix this, call kmemleak_alloc to tell kmemleak to scan elts->pages[i]
Link: https://lkml.kernel.org/r/20211124140801.87121-1-chenjun102@huawei.com
Signed-off-by: Chen Jun <chenjun102@huawei.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit 450fec13d9170127678f991698ac1a5b05c02e2f upstream.
When comparing two strings for the "onmatch" histogram trigger, fields
that are strings use string comparisons, which do not care about being
signed or not.
Do not fail to match two string fields if one is unsigned char array and
the other is a signed char array.
Link: https://lore.kernel.org/all/20211129123043.5cfd687a@gandalf.local.home/
Cc: stable@vgerk.kernel.org
Cc: Tom Zanussi <zanussi@kernel.org>
Cc: Yafang Shao <laoar.shao@gmail.com>
Fixes: b05e89ae7cf3b ("tracing: Accept different type for synthetic event fields")
Reviewed-by: Masami Hiramatsu <mhiramatsu@kernel.org>
Reported-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 6cb206508b621a9a0a2c35b60540e399225c8243 upstream.
When pid filtering is activated in an instance, all of the events trace
files for that instance has the PID_FILTER flag set. This determines
whether or not pid filtering needs to be done on the event, otherwise the
event is executed as normal.
If pid filtering is enabled when an event is created (via a dynamic event
or modules), its flag is not updated to reflect the current state, and the
events are not filtered properly.
Cc: stable@vger.kernel.org
Fixes: 3fdaf80f4a836 ("tracing: Implement event pid filtering")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit a55f224ff5f238013de8762c4287117e47b86e22 upstream.
If a event is filtered by pid and a trigger that requires processing of
the event to happen is a attached to the event, the discard portion does
not take the pid filtering into account, and the event will then be
recorded when it should not have been.
Cc: stable@vger.kernel.org
Fixes: 3fdaf80f4a836 ("tracing: Implement event pid filtering")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 1880ed71ce863318c1ce93bf324876fb5f92854f upstream.
Add missing 'tu' variable initialization in the probes loop,
otherwise the head 'tu' is used instead of added probes.
Link: https://lkml.kernel.org/r/20211123142801.182530-1-jolsa@kernel.org
Cc: stable@vger.kernel.org
Fixes: 99c9a923e97a ("tracing/uprobe: Fix double perf_event linking on multiprobe uprobe")
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 938aa33f14657c9ed9deea348b7d6f14b6d69cb7 ]
The string copies to the histogram storage has a max size of 256 bytes
(defined by MAX_FILTER_STR_VAL). Only the string size of the event field
needs to be copied to the event storage, but no more than what is in the
event storage. Although nothing should be bigger than 256 bytes, there's
no protection against overwriting of the storage if one day there is.
Copy no more than the destination size, and enforce it.
Also had to turn MAX_FILTER_STR_VAL into an unsigned int, to keep the
min() comparison of the string sizes of comparable types.
Link: https://lore.kernel.org/all/CAHk-=wjREUihCGrtRBwfX47y_KrLCGjiq3t6QtoNJpmVrAEb1w@mail.gmail.com/
Link: https://lkml.kernel.org/r/20211114132834.183429a4@rorschach.local.home
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Tom Zanussi <zanussi@kernel.org>
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Fixes: 63f84ae6b82b ("tracing/histogram: Do not copy the fixed-size char array field over the field size")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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field size
[ Upstream commit 63f84ae6b82bb4dff672f76f30c6fd7b9d3766bc ]
Do not copy the fixed-size char array field of the events over
the field size. The histogram treats char array as a string and
there are 2 types of char array in the event, fixed-size and
dynamic string. The dynamic string (__data_loc) field must be
null terminated, but the fixed-size char array field may not
be null terminated (not a string, but just a data).
In that case, histogram can copy the data after the field.
This uses the original field size for fixed-size char array
field to restrict the histogram not to access over the original
field size.
Link: https://lkml.kernel.org/r/163673292822.195747.3696966210526410250.stgit@devnote2
Fixes: 02205a6752f2 (tracing: Add support for 'field variables')
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 7ce1bb83a14019f8c396d57ec704d19478747716 ]
If CONFIG_CFI_CLANG=y, attempting to read an event histogram will cause
the kernel to panic due to failed CFI check.
1. echo 'hist:keys=common_pid' >> events/sched/sched_switch/trigger
2. cat events/sched/sched_switch/hist
3. kernel panics on attempting to read hist
This happens because the sort() function expects a generic
int (*)(const void *, const void *) pointer for the compare function.
To prevent this CFI failure, change tracing map cmp_entries_* function
signatures to match this.
Also, fix the build error reported by the kernel test robot [1].
[1] https://lore.kernel.org/r/202110141140.zzi4dRh4-lkp@intel.com/
Link: https://lkml.kernel.org/r/20211014045217.3265162-1-kaleshsingh@google.com
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit 51d157946666382e779f94c39891e8e9a020da78 upstream.
The resetting of the entire ring buffer use to simply go through and reset
each individual CPU buffer that had its own protection and synchronization.
But this was very slow, due to performing a synchronization for each CPU.
The code was reshuffled to do one disabling of all CPU buffers, followed
by a single RCU synchronization, and then the resetting of each of the CPU
buffers. But unfortunately, the mutex that prevented multiple occurrences
of resetting the buffer was not moved to the upper function, and there is
nothing to protect from it.
Take the ring buffer mutex around the global reset.
Cc: stable@vger.kernel.org
Fixes: b23d7a5f4a07a ("ring-buffer: speed up buffer resets by avoiding synchronize_rcu for each CPU")
Reported-by: "Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit ed65df63a39a3f6ed04f7258de8b6789e5021c18 upstream.
While writing an email explaining the "bit = 0" logic for a discussion on
making ftrace_test_recursion_trylock() disable preemption, I discovered a
path that makes the "not do the logic if bit is zero" unsafe.
The recursion logic is done in hot paths like the function tracer. Thus,
any code executed causes noticeable overhead. Thus, tricks are done to try
to limit the amount of code executed. This included the recursion testing
logic.
Having recursion testing is important, as there are many paths that can
end up in an infinite recursion cycle when tracing every function in the
kernel. Thus protection is needed to prevent that from happening.
Because it is OK to recurse due to different running context levels (e.g.
an interrupt preempts a trace, and then a trace occurs in the interrupt
handler), a set of bits are used to know which context one is in (normal,
softirq, irq and NMI). If a recursion occurs in the same level, it is
prevented*.
Then there are infrastructure levels of recursion as well. When more than
one callback is attached to the same function to trace, it calls a loop
function to iterate over all the callbacks. Both the callbacks and the
loop function have recursion protection. The callbacks use the
"ftrace_test_recursion_trylock()" which has a "function" set of context
bits to test, and the loop function calls the internal
trace_test_and_set_recursion() directly, with an "internal" set of bits.
If an architecture does not implement all the features supported by ftrace
then the callbacks are never called directly, and the loop function is
called instead, which will implement the features of ftrace.
Since both the loop function and the callbacks do recursion protection, it
was seemed unnecessary to do it in both locations. Thus, a trick was made
to have the internal set of recursion bits at a more significant bit
location than the function bits. Then, if any of the higher bits were set,
the logic of the function bits could be skipped, as any new recursion
would first have to go through the loop function.
This is true for architectures that do not support all the ftrace
features, because all functions being traced must first go through the
loop function before going to the callbacks. But this is not true for
architectures that support all the ftrace features. That's because the
loop function could be called due to two callbacks attached to the same
function, but then a recursion function inside the callback could be
called that does not share any other callback, and it will be called
directly.
i.e.
traced_function_1: [ more than one callback tracing it ]
call loop_func
loop_func:
trace_recursion set internal bit
call callback
callback:
trace_recursion [ skipped because internal bit is set, return 0 ]
call traced_function_2
traced_function_2: [ only traced by above callback ]
call callback
callback:
trace_recursion [ skipped because internal bit is set, return 0 ]
call traced_function_2
[ wash, rinse, repeat, BOOM! out of shampoo! ]
Thus, the "bit == 0 skip" trick is not safe, unless the loop function is
call for all functions.
Since we want to encourage architectures to implement all ftrace features,
having them slow down due to this extra logic may encourage the
maintainers to update to the latest ftrace features. And because this
logic is only safe for them, remove it completely.
[*] There is on layer of recursion that is allowed, and that is to allow
for the transition between interrupt context (normal -> softirq ->
irq -> NMI), because a trace may occur before the context update is
visible to the trace recursion logic.
Link: https://lore.kernel.org/all/609b565a-ed6e-a1da-f025-166691b5d994@linux.alibaba.com/
Link: https://lkml.kernel.org/r/20211018154412.09fcad3c@gandalf.local.home
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "James E.J. Bottomley" <James.Bottomley@hansenpartnership.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: Miroslav Benes <mbenes@suse.cz>
Cc: Joe Lawrence <joe.lawrence@redhat.com>
Cc: Colin Ian King <colin.king@canonical.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Jisheng Zhang <jszhang@kernel.org>
Cc: =?utf-8?b?546L6LSH?= <yun.wang@linux.alibaba.com>
Cc: Guo Ren <guoren@kernel.org>
Cc: stable@vger.kernel.org
Fixes: edc15cafcbfa3 ("tracing: Avoid unnecessary multiple recursion checks")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 5afedf670caf30a2b5a52da96eb7eac7dee6a9c9 ]
There is an use-after-free problem triggered by following process:
P1(sda) P2(sdb)
echo 0 > /sys/block/sdb/trace/enable
blk_trace_remove_queue
synchronize_rcu
blk_trace_free
relay_close
rcu_read_lock
__blk_add_trace
trace_note_tsk
(Iterate running_trace_list)
relay_close_buf
relay_destroy_buf
kfree(buf)
trace_note(sdb's bt)
relay_reserve
buf->offset <- nullptr deference (use-after-free) !!!
rcu_read_unlock
[ 502.714379] BUG: kernel NULL pointer dereference, address:
0000000000000010
[ 502.715260] #PF: supervisor read access in kernel mode
[ 502.715903] #PF: error_code(0x0000) - not-present page
[ 502.716546] PGD 103984067 P4D 103984067 PUD 17592b067 PMD 0
[ 502.717252] Oops: 0000 [#1] SMP
[ 502.720308] RIP: 0010:trace_note.isra.0+0x86/0x360
[ 502.732872] Call Trace:
[ 502.733193] __blk_add_trace.cold+0x137/0x1a3
[ 502.733734] blk_add_trace_rq+0x7b/0xd0
[ 502.734207] blk_add_trace_rq_issue+0x54/0xa0
[ 502.734755] blk_mq_start_request+0xde/0x1b0
[ 502.735287] scsi_queue_rq+0x528/0x1140
...
[ 502.742704] sg_new_write.isra.0+0x16e/0x3e0
[ 502.747501] sg_ioctl+0x466/0x1100
Reproduce method:
ioctl(/dev/sda, BLKTRACESETUP, blk_user_trace_setup[buf_size=127])
ioctl(/dev/sda, BLKTRACESTART)
ioctl(/dev/sdb, BLKTRACESETUP, blk_user_trace_setup[buf_size=127])
ioctl(/dev/sdb, BLKTRACESTART)
echo 0 > /sys/block/sdb/trace/enable &
// Add delay(mdelay/msleep) before kernel enters blk_trace_free()
ioctl$SG_IO(/dev/sda, SG_IO, ...)
// Enters trace_note_tsk() after blk_trace_free() returned
// Use mdelay in rcu region rather than msleep(which may schedule out)
Remove blk_trace from running_list before calling blk_trace_free() by
sysfs if blk_trace is at Blktrace_running state.
Fixes: c71a896154119f ("blktrace: add ftrace plugin")
Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Link: https://lore.kernel.org/r/20210923134921.109194-1-chengzhihao1@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
|
|
[ Upstream commit 6fe7c745f2acb73e4cc961d7f91125eef5a8861f ]
Fixes a build error when CONFIG_HIST_TRIGGERS=n with boot-time
tracing. Since the trigger_process_regex() is defined only
when CONFIG_HIST_TRIGGERS=y, if it is disabled, the 'actions'
event option also must be disabled.
Link: https://lkml.kernel.org/r/162856123376.203126.582144262622247352.stgit@devnote2
Fixes: 81a59555ff15 ("tracing/boot: Add per-event settings")
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
|
|
[ Upstream commit 8e242060c6a4947e8ae7d29794af6a581db08841 ]
Since kprobe_events and uprobe_events only check whether the
other same-type probe event has the same name or not, if the
user gives the same name of the existing tracepoint event (or
the other type of probe events), it silently fails to create
the tracefs entry (but registered.) as below.
/sys/kernel/tracing # ls events/task/task_rename
enable filter format hist id trigger
/sys/kernel/tracing # echo p:task/task_rename vfs_read >> kprobe_events
[ 113.048508] Could not create tracefs 'task_rename' directory
/sys/kernel/tracing # cat kprobe_events
p:task/task_rename vfs_read
To fix this issue, check whether the existing events have the
same name or not in trace_probe_register_event_call(). If exists,
it rejects to register the new event.
Link: https://lkml.kernel.org/r/162936876189.187130.17558311387542061930.stgit@devnote2
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
|
|
[ Upstream commit 5acce0bff2a0420ce87d4591daeb867f47d552c2 ]
The following commands:
# echo 'read_max u64 size;' > synthetic_events
# echo 'hist:keys=common_pid:count=count:onmax($count).trace(read_max,count)' > events/syscalls/sys_enter_read/trigger
Causes:
BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 0 P4D 0
Oops: 0000 [#1] PREEMPT SMP
CPU: 4 PID: 1763 Comm: bash Not tainted 5.14.0-rc2-test+ #155
Hardware name: Hewlett-Packard HP Compaq Pro 6300 SFF/339A, BIOS K01
v03.03 07/14/2016
RIP: 0010:strcmp+0xc/0x20
Code: 75 f7 31 c0 0f b6 0c 06 88 0c 02 48 83 c0 01 84 c9 75 f1 4c 89 c0
c3 0f 1f 80 00 00 00 00 31 c0 eb 08 48 83 c0 01 84 d2 74 0f <0f> b6 14 07
3a 14 06 74 ef 19 c0 83 c8 01 c3 31 c0 c3 66 90 48 89
RSP: 0018:ffffb5fdc0963ca8 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffffffffb3a4e040 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffff9714c0d0b640 RDI: 0000000000000000
RBP: 0000000000000000 R08: 00000022986b7cde R09: ffffffffb3a4dff8
R10: 0000000000000000 R11: 0000000000000000 R12: ffff9714c50603c8
R13: 0000000000000000 R14: ffff97143fdf9e48 R15: ffff9714c01a2210
FS: 00007f1fa6785740(0000) GS:ffff9714da400000(0000)
knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000002d863004 CR4: 00000000001706e0
Call Trace:
__find_event_file+0x4e/0x80
action_create+0x6b7/0xeb0
? kstrdup+0x44/0x60
event_hist_trigger_func+0x1a07/0x2130
trigger_process_regex+0xbd/0x110
event_trigger_write+0x71/0xd0
vfs_write+0xe9/0x310
ksys_write+0x68/0xe0
do_syscall_64+0x3b/0x90
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f1fa6879e87
The problem was the "trace(read_max,count)" where the "count" should be
"$count" as "onmax()" only handles variables (although it really should be
able to figure out that "count" is a field of sys_enter_read). But there's
a path that does not find the variable and ends up passing a NULL for the
event, which ends up getting passed to "strcmp()".
Add a check for NULL to return and error on the command with:
# cat error_log
hist:syscalls:sys_enter_read: error: Couldn't create or find variable
Command: hist:keys=common_pid:count=count:onmax($count).trace(read_max,count)
^
Link: https://lkml.kernel.org/r/20210808003011.4037f8d0@oasis.local.home
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: stable@vger.kernel.org
Fixes: 50450603ec9cb tracing: Add 'onmax' hist trigger action support
Reviewed-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
|
|
commit 51e1bb9eeaf7868db56e58f47848e364ab4c4129 upstream.
Back then, commit 96ae52279594 ("bpf: Add bpf_probe_write_user BPF helper
to be called in tracers") added the bpf_probe_write_user() helper in order
to allow to override user space memory. Its original goal was to have a
facility to "debug, divert, and manipulate execution of semi-cooperative
processes" under CAP_SYS_ADMIN. Write to kernel was explicitly disallowed
since it would otherwise tamper with its integrity.
One use case was shown in cf9b1199de27 ("samples/bpf: Add test/example of
using bpf_probe_write_user bpf helper") where the program DNATs traffic
at the time of connect(2) syscall, meaning, it rewrites the arguments to
a syscall while they're still in userspace, and before the syscall has a
chance to copy the argument into kernel space. These days we have better
mechanisms in BPF for achieving the same (e.g. for load-balancers), but
without having to write to userspace memory.
Of course the bpf_probe_write_user() helper can also be used to abuse
many other things for both good or bad purpose. Outside of BPF, there is
a similar mechanism for ptrace(2) such as PTRACE_PEEK{TEXT,DATA} and
PTRACE_POKE{TEXT,DATA}, but would likely require some more effort.
Commit 96ae52279594 explicitly dedicated the helper for experimentation
purpose only. Thus, move the helper's availability behind a newly added
LOCKDOWN_BPF_WRITE_USER lockdown knob so that the helper is disabled under
the "integrity" mode. More fine-grained control can be implemented also
from LSM side with this change.
Fixes: 96ae52279594 ("bpf: Add bpf_probe_write_user BPF helper to be called in tracers")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
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commit ff41c28c4b54052942180d8b3f49e75f1445135a upstream.
The event_trace_add_tracer() can fail. In this case, it leads to a crash
in start_creating with below call stack. Handle the error scenario
properly in trace_array_create_dir.
Call trace:
down_write+0x7c/0x204
start_creating.25017+0x6c/0x194
tracefs_create_file+0xc4/0x2b4
init_tracer_tracefs+0x5c/0x940
trace_array_create_dir+0x58/0xb4
trace_array_create+0x1bc/0x2b8
trace_array_get_by_name+0xdc/0x18c
Link: https://lkml.kernel.org/r/1627651386-21315-1-git-send-email-kamaagra@codeaurora.org
Cc: stable@vger.kernel.org
Fixes: 4114fbfd02f1 ("tracing: Enable creating new instance early boot")
Signed-off-by: Kamal Agrawal <kamaagra@codeaurora.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
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commit a9d10ca4986571bffc19778742d508cc8dd13e02 upstream.
Since the string type can not be the target of the addition / subtraction
operation, it must be rejected. Without this fix, the string type silently
converted to digits.
Link: https://lkml.kernel.org/r/162742654278.290973.1523000673366456634.stgit@devnote2
Cc: stable@vger.kernel.org
Fixes: 100719dcef447 ("tracing: Add simple expression support to hist triggers")
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 2c05caa7ba8803209769b9e4fe02c38d77ae88d0 upstream.
When working on my user space applications, I found a bug in the synthetic
event code where the automated synthetic event field was not matching the
event field calculation it was attached to. Looking deeper into it, it was
because the calculation hist_field was not given a size.
The synthetic event fields are matched to their hist_fields either by
having the field have an identical string type, or if that does not match,
then the size and signed values are used to match the fields.
The problem arose when I tried to match a calculation where the fields
were "unsigned int". My tool created a synthetic event of type "u32". But
it failed to match. The string was:
diff=field1-field2:onmatch(event).trace(synth,$diff)
Adding debugging into the kernel, I found that the size of "diff" was 0.
And since it was given "unsigned int" as a type, the histogram fallback
code used size and signed. The signed matched, but the size of u32 (4) did
not match zero, and the event failed to be created.
This can be worse if the field you want to match is not one of the
acceptable fields for a synthetic event. As event fields can have any type
that is supported in Linux, this can cause an issue. For example, if a
type is an enum. Then there's no way to use that with any calculations.
Have the calculation field simply take on the size of what it is
calculating.
Link: https://lkml.kernel.org/r/20210730171951.59c7743f@oasis.local.home
Cc: Tom Zanussi <zanussi@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: stable@vger.kernel.org
Fixes: 100719dcef447 ("tracing: Add simple expression support to hist triggers")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit 3b13911a2fd0dd0146c9777a254840c5466cf120 upstream.
Performing the following:
># echo 'wakeup_lat s32 pid; u64 delta; char wake_comm[]' > synthetic_events
># echo 'hist:keys=pid:__arg__1=common_timestamp.usecs' > events/sched/sched_waking/trigger
># echo 'hist:keys=next_pid:pid=next_pid,delta=common_timestamp.usecs-$__arg__1:onmatch(sched.sched_waking).trace(wakeup_lat,$pid,$delta,prev_comm)'\
> events/sched/sched_switch/trigger
># echo 1 > events/synthetic/enable
Crashed the kernel:
BUG: kernel NULL pointer dereference, address: 000000000000001b
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 0 P4D 0
Oops: 0000 [#1] PREEMPT SMP
CPU: 7 PID: 0 Comm: swapper/7 Not tainted 5.13.0-rc5-test+ #104
Hardware name: Hewlett-Packard HP Compaq Pro 6300 SFF/339A, BIOS K01 v03.03 07/14/2016
RIP: 0010:strlen+0x0/0x20
Code: f6 82 80 2b 0b bc 20 74 11 0f b6 50 01 48 83 c0 01 f6 82 80 2b 0b bc
20 75 ef c3 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 <80> 3f 00 74 10
48 89 f8 48 83 c0 01 80 38 9 f8 c3 31
RSP: 0018:ffffaa75000d79d0 EFLAGS: 00010046
RAX: 0000000000000002 RBX: ffff9cdb55575270 RCX: 0000000000000000
RDX: ffff9cdb58c7a320 RSI: ffffaa75000d7b40 RDI: 000000000000001b
RBP: ffffaa75000d7b40 R08: ffff9cdb40a4f010 R09: ffffaa75000d7ab8
R10: ffff9cdb4398c700 R11: 0000000000000008 R12: ffff9cdb58c7a320
R13: ffff9cdb55575270 R14: ffff9cdb58c7a000 R15: 0000000000000018
FS: 0000000000000000(0000) GS:ffff9cdb5aa00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000000001b CR3: 00000000c0612006 CR4: 00000000001706e0
Call Trace:
trace_event_raw_event_synth+0x90/0x1d0
action_trace+0x5b/0x70
event_hist_trigger+0x4bd/0x4e0
? cpumask_next_and+0x20/0x30
? update_sd_lb_stats.constprop.0+0xf6/0x840
? __lock_acquire.constprop.0+0x125/0x550
? find_held_lock+0x32/0x90
? sched_clock_cpu+0xe/0xd0
? lock_release+0x155/0x440
? update_load_avg+0x8c/0x6f0
? enqueue_entity+0x18a/0x920
? __rb_reserve_next+0xe5/0x460
? ring_buffer_lock_reserve+0x12a/0x3f0
event_triggers_call+0x52/0xe0
trace_event_buffer_commit+0x1ae/0x240
trace_event_raw_event_sched_switch+0x114/0x170
__traceiter_sched_switch+0x39/0x50
__schedule+0x431/0xb00
schedule_idle+0x28/0x40
do_idle+0x198/0x2e0
cpu_startup_entry+0x19/0x20
secondary_startup_64_no_verify+0xc2/0xcb
The reason is that the dynamic events array keeps track of the field
position of the fields array, via the field_pos variable in the
synth_field structure. Unfortunately, that field is a boolean for some
reason, which means any field_pos greater than 1 will be a bug (in this
case it was 2).
Link: https://lkml.kernel.org/r/20210721191008.638bce34@oasis.local.home
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: stable@vger.kernel.org
Fixes: bd82631d7ccdc ("tracing: Add support for dynamic strings to synthetic events")
Reviewed-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
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commit 67f0d6d9883c13174669f88adac4f0ee656cc16a upstream.
The "rb_per_cpu_empty()" misinterpret the condition (as not-empty) when
"head_page" and "commit_page" of "struct ring_buffer_per_cpu" points to
the same buffer page, whose "buffer_data_page" is empty and "read" field
is non-zero.
An error scenario could be constructed as followed (kernel perspective):
1. All pages in the buffer has been accessed by reader(s) so that all of
them will have non-zero "read" field.
2. Read and clear all buffer pages so that "rb_num_of_entries()" will
return 0 rendering there's no more data to read. It is also required
that the "read_page", "commit_page" and "tail_page" points to the same
page, while "head_page" is the next page of them.
3. Invoke "ring_buffer_lock_reserve()" with large enough "length"
so that it shot pass the end of current tail buffer page. Now the
"head_page", "commit_page" and "tail_page" points to the same page.
4. Discard current event with "ring_buffer_discard_commit()", so that
"head_page", "commit_page" and "tail_page" points to a page whose buffer
data page is now empty.
When the error scenario has been constructed, "tracing_read_pipe" will
be trapped inside a deadloop: "trace_empty()" returns 0 since
"rb_per_cpu_empty()" returns 0 when it hits the CPU containing such
constructed ring buffer. Then "trace_find_next_entry_inc()" always
return NULL since "rb_num_of_entries()" reports there's no more entry
to read. Finally "trace_seq_to_user()" returns "-EBUSY" spanking
"tracing_read_pipe" back to the start of the "waitagain" loop.
I've also written a proof-of-concept script to construct the scenario
and trigger the bug automatically, you can use it to trace and validate
my reasoning above:
https://github.com/aegistudio/RingBufferDetonator.git
Tests has been carried out on linux kernel 5.14-rc2
(2734d6c1b1a089fb593ef6a23d4b70903526fe0c), my fixed version
of kernel (for testing whether my update fixes the bug) and
some older kernels (for range of affected kernels). Test result is
also attached to the proof-of-concept repository.
Link: https://lore.kernel.org/linux-trace-devel/YPaNxsIlb2yjSi5Y@aegistudio/
Link: https://lore.kernel.org/linux-trace-devel/YPgrN85WL9VyrZ55@aegistudio
Cc: stable@vger.kernel.org
Fixes: bf41a158cacba ("ring-buffer: make reentrant")
Suggested-by: Linus Torvalds <torvalds@linuxfoundation.org>
Signed-off-by: Haoran Luo <www@aegistudio.net>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 1e3bac71c5053c99d438771fc9fa5082ae5d90aa upstream.
Currently the histogram logic allows the user to write "cpu" in as an
event field, and it will record the CPU that the event happened on.
The problem with this is that there's a lot of events that have "cpu"
as a real field, and using "cpu" as the CPU it ran on, makes it
impossible to run histograms on the "cpu" field of events.
For example, if I want to have a histogram on the count of the
workqueue_queue_work event on its cpu field, running:
># echo 'hist:keys=cpu' > events/workqueue/workqueue_queue_work/trigger
Gives a misleading and wrong result.
Change the command to "common_cpu" as no event should have "common_*"
fields as that's a reserved name for fields used by all events. And
this makes sense here as common_cpu would be a field used by all events.
Now we can even do:
># echo 'hist:keys=common_cpu,cpu if cpu < 100' > events/workqueue/workqueue_queue_work/trigger
># cat events/workqueue/workqueue_queue_work/hist
# event histogram
#
# trigger info: hist:keys=common_cpu,cpu:vals=hitcount:sort=hitcount:size=2048 if cpu < 100 [active]
#
{ common_cpu: 0, cpu: 2 } hitcount: 1
{ common_cpu: 0, cpu: 4 } hitcount: 1
{ common_cpu: 7, cpu: 7 } hitcount: 1
{ common_cpu: 0, cpu: 7 } hitcount: 1
{ common_cpu: 0, cpu: 1 } hitcount: 1
{ common_cpu: 0, cpu: 6 } hitcount: 2
{ common_cpu: 0, cpu: 5 } hitcount: 2
{ common_cpu: 1, cpu: 1 } hitcount: 4
{ common_cpu: 6, cpu: 6 } hitcount: 4
{ common_cpu: 5, cpu: 5 } hitcount: 14
{ common_cpu: 4, cpu: 4 } hitcount: 26
{ common_cpu: 0, cpu: 0 } hitcount: 39
{ common_cpu: 2, cpu: 2 } hitcount: 184
Now for backward compatibility, I added a trick. If "cpu" is used, and
the field is not found, it will fall back to "common_cpu" and work as
it did before. This way, it will still work for old programs that use
"cpu" to get the actual CPU, but if the event has a "cpu" as a field, it
will get that event's "cpu" field, which is probably what it wants
anyway.
I updated the tracefs/README to include documentation about both the
common_timestamp and the common_cpu. This way, if that text is present in
the README, then an application can know that common_cpu is supported over
just plain "cpu".
Link: https://lkml.kernel.org/r/20210721110053.26b4f641@oasis.local.home
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: stable@vger.kernel.org
Fixes: 8b7622bf94a44 ("tracing: Add cpu field for hist triggers")
Reviewed-by: Tom Zanussi <zanussi@kernel.org>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
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commit 704adfb5a9978462cd861f170201ae2b5e3d3a80 upstream.
The histogram logic was allowing events with char * pointers to be used as
normal strings. But it was easy to crash the kernel with:
# echo 'hist:keys=filename' > events/syscalls/sys_enter_openat/trigger
And open some files, and boom!
BUG: unable to handle page fault for address: 00007f2ced0c3280
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 1173fa067 P4D 1173fa067 PUD 1171b6067 PMD 1171dd067 PTE 0
Oops: 0000 [#1] PREEMPT SMP
CPU: 6 PID: 1810 Comm: cat Not tainted 5.13.0-rc5-test+ #61
Hardware name: Hewlett-Packard HP Compaq Pro 6300 SFF/339A, BIOS K01
v03.03 07/14/2016
RIP: 0010:strlen+0x0/0x20
Code: f6 82 80 2a 0b a9 20 74 11 0f b6 50 01 48 83 c0 01 f6 82 80 2a 0b
a9 20 75 ef c3 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 <80> 3f 00 74
10 48 89 f8 48 83 c0 01 80 38 00 75 f7 48 29 f8 c3
RSP: 0018:ffffbdbf81567b50 EFLAGS: 00010246
RAX: 0000000000000003 RBX: ffff93815cdb3800 RCX: ffff9382401a22d0
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 00007f2ced0c3280
RBP: 0000000000000100 R08: ffff9382409ff074 R09: ffffbdbf81567c98
R10: ffff9382409ff074 R11: 0000000000000000 R12: ffff9382409ff074
R13: 0000000000000001 R14: ffff93815a744f00 R15: 00007f2ced0c3280
FS: 00007f2ced0f8580(0000) GS:ffff93825a800000(0000)
knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f2ced0c3280 CR3: 0000000107069005 CR4: 00000000001706e0
Call Trace:
event_hist_trigger+0x463/0x5f0
? find_held_lock+0x32/0x90
? sched_clock_cpu+0xe/0xd0
? lock_release+0x155/0x440
? kernel_init_free_pages+0x6d/0x90
? preempt_count_sub+0x9b/0xd0
? kernel_init_free_pages+0x6d/0x90
? get_page_from_freelist+0x12c4/0x1680
? __rb_reserve_next+0xe5/0x460
? ring_buffer_lock_reserve+0x12a/0x3f0
event_triggers_call+0x52/0xe0
ftrace_syscall_enter+0x264/0x2c0
syscall_trace_enter.constprop.0+0x1ee/0x210
do_syscall_64+0x1c/0x80
entry_SYSCALL_64_after_hwframe+0x44/0xae
Where it triggered a fault on strlen(key) where key was the filename.
The reason is that filename is a char * to user space, and the histogram
code just blindly dereferenced it, with obvious bad results.
I originally tried to use strncpy_from_user/kernel_nofault() but found
that there's other places that its dereferenced and not worth the effort.
Just do not allow "char *" to act like strings.
Link: https://lkml.kernel.org/r/20210715000206.025df9d2@rorschach.local.home
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Tzvetomir Stoyanov <tz.stoyanov@gmail.com>
Cc: stable@vger.kernel.org
Acked-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Tom Zanussi <zanussi@kernel.org>
Fixes: 79e577cbce4c4 ("tracing: Support string type key properly")
Fixes: 5967bd5c4239 ("tracing: Let filter_assign_type() detect FILTER_PTR_STRING")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 4030a6e6a6a4a42ff8c18414c9e0c93e24cc70b8 upstream.
Currently tgid_map is sized at PID_MAX_DEFAULT entries, which means that
on systems where pid_max is configured higher than PID_MAX_DEFAULT the
ftrace record-tgid option doesn't work so well. Any tasks with PIDs
higher than PID_MAX_DEFAULT are simply not recorded in tgid_map, and
don't show up in the saved_tgids file.
In particular since systemd v243 & above configure pid_max to its
highest possible 1<<22 value by default on 64 bit systems this renders
the record-tgids option of little use.
Increase the size of tgid_map to the configured pid_max instead,
allowing it to cover the full range of PIDs up to the maximum value of
PID_MAX_LIMIT if the system is configured that way.
On 64 bit systems with pid_max == PID_MAX_LIMIT this will increase the
size of tgid_map from 256KiB to 16MiB. Whilst this 64x increase in
memory overhead sounds significant 64 bit systems are presumably best
placed to accommodate it, and since tgid_map is only allocated when th |
