linux-stable.git/kernel/trace/trace_probe.c, branch v6.1.178

bitops: make BYTES_TO_BITS() treewide-available

2026-07-24T13:55:12+00:00

[ Upstream commit 7d8296b250f2eed73f1758607926d4d258dea5d4 ]

Avoid open-coding that simple expression each time by moving
BYTES_TO_BITS() from the probes code to  to export
it to the rest of the kernel.
Simplify the macro while at it. `BITS_PER_LONG / sizeof(long)` always
equals to %BITS_PER_BYTE, regardless of the target architecture.
Do the same for the tools ecosystem as well (incl. its version of
bitops.h). The previous implementation had its implicit type of long,
while the new one is int, so adjust the format literal accordingly in
the perf code.

Suggested-by: Andy Shevchenko 
Reviewed-by: Przemek Kitszel 
Acked-by: Yury Norov 
Signed-off-by: Alexander Lobakin 
Signed-off-by: David S. Miller 
Stable-dep-of: 55052184ac90 ("iio: common: st_sensors: honour channel endianness in read_axis_data")
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

tracing/probes: Fix double addition of offset for @+FOFFSET

2026-07-24T13:55:09+00:00

commit 9a667b7750dda88cbf1cca96a53a2163b2ee71f7 upstream.

Since commit 533059281ee5 ("tracing: probeevent: Introduce new argument
 fetching code") wrongly use @offset local variable during the parsing,
the offset value is added twice when dereferencing.
Reset the @offset after setting it in FETCH_OP_FOFFS.

Link: https://lore.kernel.org/all/178217905962.643090.1978577464942171332.stgit@devnote2/

Fixes: 533059281ee5 ("tracing: probeevent: Introduce new argument fetching code")
Signed-off-by: Masami Hiramatsu (Google) 
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman

tracing/probes: Limit size of event probe to 3K

2026-06-19T11:37:24+00:00

[ Upstream commit b2aa3b4d64e460ac606f386c24e7d8a873ce6f1a ]

There currently isn't a max limit an event probe can be. One could make an
event greater than PAGE_SIZE, which makes the event useless because if
it's bigger than the max event that can be recorded into the ring buffer,
then it will never be recorded.

A event probe should never need to be greater than 3K, so make that the
max size. As long as the max is less than the max that can be recorded
onto the ring buffer, it should be fine.

Cc: stable@vger.kernel.org
Cc: Mathieu Desnoyers 
Acked-by: Masami Hiramatsu (Google) 
Fixes: 93ccae7a22274 ("tracing/kprobes: Support basic types on dynamic events")
Link: https://patch.msgid.link/20260428122302.706610ba@gandalf.local.home
Signed-off-by: Steven Rostedt 
[ changed `ctx->offset` to `offset` and `goto fail` to `goto out` ]
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

tracing/probe: reject non-closed empty immediate strings

2026-06-01T15:38:34+00:00

[ Upstream commit 4346be6577aaa04586167402ae87bbdbe32484a4 ]

parse_probe_arg() accepts quoted immediate strings and passes the body
after the opening quote to __parse_imm_string(). That helper currently
computes strlen(str) and immediately dereferences str[len - 1], which
underflows when the body is empty and not closed with double-quotation.

Reject empty non-closed immediate strings before checking for the closing quote.

Link: https://lore.kernel.org/all/20260401160315.88518-1-pengpeng@iscas.ac.cn/

Fixes: a42e3c4de964 ("tracing/probe: Add immediate string parameter support")
Signed-off-by: Pengpeng Hou 
Reviewed-by: Steven Rostedt (Google) 
Signed-off-by: Masami Hiramatsu (Google) 
Signed-off-by: Sasha Levin

tracing: probes: Fix a possible race in trace_probe_log APIs

2025-05-22T12:09:59+00:00

[ Upstream commit fd837de3c9cb1a162c69bc1fb1f438467fe7f2f5 ]

Since the shared trace_probe_log variable can be accessed and
modified via probe event create operation of kprobe_events,
uprobe_events, and dynamic_events, it should be protected.
In the dynamic_events, all operations are serialized by
`dyn_event_ops_mutex`. But kprobe_events and uprobe_events
interfaces are not serialized.

To solve this issue, introduces dyn_event_create(), which runs
create() operation under the mutex, for kprobe_events and
uprobe_events. This also uses lockdep to check the mutex is
held when using trace_probe_log* APIs.

Link: https://lore.kernel.org/all/174684868120.551552.3068655787654268804.stgit@devnote2/

Reported-by: Paul Cacheux 
Closes: https://lore.kernel.org/all/20250510074456.805a16872b591e2971a4d221@kernel.org/
Fixes: ab105a4fb894 ("tracing: Use tracing error_log with probe events")
Signed-off-by: Masami Hiramatsu (Google) 
Signed-off-by: Sasha Levin

tracing: Consider the NULL character when validating the event length

2024-11-01T00:56:03+00:00

[ Upstream commit 0b6e2e22cb23105fcb171ab92f0f7516c69c8471 ]

strlen() returns a string length excluding the null byte. If the string
length equals to the maximum buffer length, the buffer will have no
space for the NULL terminating character.

This commit checks this condition and returns failure for it.

Link: https://lore.kernel.org/all/20241007144724.920954-1-leo.yan@arm.com/

Fixes: dec65d79fd26 ("tracing/probe: Check event name length correctly")
Signed-off-by: Leo Yan 
Reviewed-by: Steven Rostedt (Google) 
Signed-off-by: Masami Hiramatsu (Google) 
Signed-off-by: Sasha Levin

Revert "tracing: Add "(fault)" name injection to kernel probes"

2023-08-03T08:23:55+00:00

[ Upstream commit 4ed8f337dee32df71435689c19d22e4ee846e15a ]

This reverts commit 2e9906f84fc7c99388bb7123ade167250d50f1c0.

It was turned out that commit 2e9906f84fc7 ("tracing: Add "(fault)"
name injection to kernel probes") did not work correctly and probe
events still show just '(fault)' (instead of '"(fault)"'). Also,
current '(fault)' is more explicit that it faulted.

This also moves FAULT_STRING macro to trace.h so that synthetic
event can keep using it, and uses it in trace_probe.c too.

Link: https://lore.kernel.org/all/168908495772.123124.1250788051922100079.stgit@devnote2/
Link: https://lore.kernel.org/all/20230706230642.3793a593@rorschach.local.home/

Cc: stable@vger.kernel.org
Cc: Andrew Morton 
Cc: Tom Zanussi 
Signed-off-by: Masami Hiramatsu (Google) 
Reviewed-by: Steven Rostedt (Google) 
Stable-dep-of: 797311bce5c2 ("tracing/probes: Fix to record 0-length data_loc in fetch_store_string*() if fails")
Signed-off-by: Sasha Levin

tracing/probes: Add symstr type for dynamic events

2023-08-03T08:23:54+00:00

[ Upstream commit b26a124cbfa80f42bfc4e63e1d5643ca98159d66 ]

Add 'symstr' type for storing the kernel symbol as a string data
instead of the symbol address. This allows us to filter the
events by wildcard symbol name.

e.g.
  # echo 'e:wqfunc workqueue.workqueue_execute_start symname=$function:symstr' >> dynamic_events
  # cat events/eprobes/wqfunc/format
  name: wqfunc
  ID: 2110
  format:
  	field:unsigned short common_type;	offset:0;	size:2;	signed:0;
  	field:unsigned char common_flags;	offset:2;	size:1;	signed:0;
  	field:unsigned char common_preempt_count;	offset:3;	size:1;	signed:0;
  	field:int common_pid;	offset:4;	size:4;	signed:1;

  	field:__data_loc char[] symname;	offset:8;	size:4;	signed:1;

  print fmt: " symname=\"%s\"", __get_str(symname)

Note that there is already 'symbol' type which just change the
print format (so it still stores the symbol address in the tracing
ring buffer.) On the other hand, 'symstr' type stores the actual
"symbol+offset/size" data as a string.

Link: https://lore.kernel.org/all/166679930847.1528100.4124308529180235965.stgit@devnote3/

Signed-off-by: Masami Hiramatsu (Google) 
Stable-dep-of: 66bcf65d6cf0 ("tracing/probes: Fix to avoid double count of the string length on the array")
Signed-off-by: Sasha Levin

tracing/probes: Handle system names with hyphens

2023-01-07T10:11:48+00:00

commit 575b76cb885532aae13a9d979fd476bb2b156cb9 upstream.

When creating probe names, a check is done to make sure it matches basic C
standard variable naming standards. Basically, starts with alphabetic or
underline, and then the rest of the characters have alpha-numeric or
underline in them.

But system names do not have any true naming conventions, as they are
created by the TRACE_SYSTEM macro and nothing tests to see what they are.
The "xhci-hcd" trace events has a '-' in the system name. When trying to
attach a eprobe to one of these trace points, it fails because the system
name does not follow the variable naming convention because of the
hyphen, and the eprobe checks fail on this.

Allow hyphens in the system name so that eprobes can attach to the
"xhci-hcd" trace events.

Link: https://lore.kernel.org/all/Y3eJ8GiGnEvVd8%2FN@macondo/
Link: https://lore.kernel.org/linux-trace-kernel/20221122122345.160f5077@gandalf.local.home

Cc: Masami Hiramatsu 
Cc: stable@vger.kernel.org
Fixes: 5b7a96220900e ("tracing/probe: Check event/group naming rule at parsing")
Reported-by: Rafael Mendonca 
Signed-off-by: Steven Rostedt (Google) 
Signed-off-by: Greg Kroah-Hartman

tracing/probes: Have kprobes and uprobes use $COMM too

2022-08-21T19:56:08+00:00

Both $comm and $COMM can be used to get current->comm in eprobes and the
filtering and histogram logic. Make kprobes and uprobes consistent in this
regard and allow both $comm and $COMM as well. Currently kprobes and
uprobes only handle $comm, which is inconsistent with the other utilities,
and can be confusing to users.

Link: https://lkml.kernel.org/r/20220820134401.317014913@goodmis.org
Link: https://lore.kernel.org/all/20220820220442.776e1ddaf8836e82edb34d01@kernel.org/

Cc: stable@vger.kernel.org
Cc: Ingo Molnar 
Cc: Andrew Morton 
Cc: Tzvetomir Stoyanov 
Cc: Tom Zanussi 
Fixes: 533059281ee5 ("tracing: probeevent: Introduce new argument fetching code")
Suggested-by: Masami Hiramatsu (Google) 
Acked-by: Masami Hiramatsu (Google) 
Signed-off-by: Steven Rostedt (Google)