linux.git/kernel/trace/trace_probe.c, branch v5.10.258

tracing/probe: reject non-closed empty immediate strings

2026-06-01T15:29:09+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: Consider the NULL character when validating the event length

2024-11-08T15:21:59+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

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

2022-08-25T09:38:23+00:00

commit ab8384442ee512fc0fc72deeb036110843d0e7ff upstream.

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) 
Signed-off-by: Greg Kroah-Hartman

tracing/probes: Reject events which have the same name of existing one

2021-09-22T10:28:00+00:00

[ 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 
Signed-off-by: Steven Rostedt (VMware) 
Signed-off-by: Sasha Levin

tracing/probe: Fix memleak in fetch_op_data operations

2020-06-17T01:21:02+00:00

kmemleak report:
    [<57dcc2ca>] __kmalloc_track_caller+0x139/0x2b0
    [] kstrndup+0x37/0x80
    [] parse_probe_arg.isra.7+0x3cc/0x630
    [<055bf2ba>] traceprobe_parse_probe_arg+0x2f5/0x810
    [<655a7766>] trace_kprobe_create+0x2ca/0x950
    [<4fc6a02a>] create_or_delete_trace_kprobe+0xf/0x30
    [<6d1c8a52>] trace_run_command+0x67/0x80
    [] trace_parse_run_command+0xa7/0x140
    [] probes_write+0x10/0x20
    [<2027641c>] __vfs_write+0x30/0x1e0
    [<6a4aeee1>] vfs_write+0x96/0x1b0
    [<3517fb7d>] ksys_write+0x53/0xc0
    [] __ia32_sys_write+0x15/0x20
    [] do_syscall_32_irqs_on+0x3d/0x260
    [] do_fast_syscall_32+0x39/0xb0
    [] entry_SYSENTER_32+0xaf/0x102

Post parse_probe_arg(), the FETCH_OP_DATA operation type is overwritten
to FETCH_OP_ST_STRING, as a result memory is never freed since
traceprobe_free_probe_arg() iterates only over SYMBOL and DATA op types

Setup fetch string operation correctly after fetch_op_data operation.

Link: https://lkml.kernel.org/r/20200615143034.GA1734@cosmos

Cc: stable@vger.kernel.org
Fixes: a42e3c4de964 ("tracing/probe: Add immediate string parameter support")
Acked-by: Masami Hiramatsu 
Signed-off-by: Vamshi K Sthambamkadi 
Signed-off-by: Steven Rostedt (VMware)

tracing/probe: reverse arguments to list_add

2020-05-20T01:10:50+00:00

Elsewhere in the file, the function trace_kprobe_has_same_kprobe uses
a trace_probe_event.probes object as the second argument of
list_for_each_entry, ie as a list head, while the list_for_each_entry
iterates over the list fields of the trace_probe structures, making
them the list elements.  So, exchange the arguments on the list_add
call to put the list head in the second argument.

Since both list_head structures were just initialized, this problem
did not cause any loss of information.

Link: https://lkml.kernel.org/r/1588879808-24488-1-git-send-email-Julia.Lawall@inria.fr

Fixes: 60d53e2c3b75 ("tracing/probe: Split trace_event related data from trace_probe")
Acked-by: Masami Hiramatsu 
Signed-off-by: Julia Lawall 
Signed-off-by: Steven Rostedt (VMware)

tracing/kprobes: Have uname use __get_str() in print_fmt

2020-01-27T15:56:02+00:00

Thomas Richter reported:

> Test case 66 'Use vfs_getname probe to get syscall args filenames'
> is broken on s390, but works on x86. The test case fails with:
>
>  [root@m35lp76 perf]# perf test -F 66
>  66: Use vfs_getname probe to get syscall args filenames
>            :Recording open file:
>  [ perf record: Woken up 1 times to write data ]
>  [ perf record: Captured and wrote 0.004 MB /tmp/__perf_test.perf.data.TCdYj\
> 	 (20 samples) ]
>  Looking at perf.data file for vfs_getname records for the file we touched:
>   FAILED!
>   [root@m35lp76 perf]#

The root cause was the print_fmt of the kprobe event that referenced the
"ustring"

> Setting up the kprobe event using perf command:
>
>  # ./perf probe "vfs_getname=getname_flags:72 pathname=filename:ustring"
>
> generates this format file:
>   [root@m35lp76 perf]# cat /sys/kernel/debug/tracing/events/probe/\
> 	  vfs_getname/format
>   name: vfs_getname
>   ID: 1172
>   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:unsigned long __probe_ip; offset:8; size:8; signed:0;
>     field:__data_loc char[] pathname; offset:16; size:4; signed:1;
>
>     print fmt: "(%lx) pathname=\"%s\"", REC->__probe_ip, REC->pathname

Instead of using "__get_str(pathname)" it referenced it directly.

Link: http://lkml.kernel.org/r/20200124100742.4050c15e@gandalf.local.home

Cc: stable@vger.kernel.org
Fixes: 88903c464321 ("tracing/probe: Add ustring type for user-space string")
Acked-by: Masami Hiramatsu 
Reported-by: Thomas Richter 
Tested-by: Thomas Richter 
Signed-off-by: Steven Rostedt (VMware)

tracing/uprobe: Fix to make trace_uprobe_filter alignment safe

2020-01-22T12:09:20+00:00

Commit 99c9a923e97a ("tracing/uprobe: Fix double perf_event
linking on multiprobe uprobe") moved trace_uprobe_filter on
trace_probe_event. However, since it introduced a flexible
data structure with char array and type casting, the
alignment of trace_uprobe_filter can be broken.

This changes the type of the array to trace_uprobe_filter
data strucure to fix it.

Link: http://lore.kernel.org/r/20200120124022.GA14897@hirez.programming.kicks-ass.net
Link: http://lkml.kernel.org/r/157966340499.5107.10978352478952144902.stgit@devnote2

Fixes: 99c9a923e97a ("tracing/uprobe: Fix double perf_event linking on multiprobe uprobe")
Suggested-by: Peter Zijlstra 
Signed-off-by: Masami Hiramatsu 
Signed-off-by: Steven Rostedt (VMware)

tracing/uprobe: Fix double perf_event linking on multiprobe uprobe

2020-01-14T20:57:59+00:00

Fix double perf_event linking to trace_uprobe_filter on
multiple uprobe event by moving trace_uprobe_filter under
trace_probe_event.

In uprobe perf event, trace_uprobe_filter data structure is
managing target mm filters (in perf_event) related to each
uprobe event.

Since commit 60d53e2c3b75 ("tracing/probe: Split trace_event
related data from trace_probe") left the trace_uprobe_filter
data structure in trace_uprobe, if a trace_probe_event has
multiple trace_uprobe (multi-probe event), a perf_event is
added to different trace_uprobe_filter on each trace_uprobe.
This leads a linked list corruption.

To fix this issue, move trace_uprobe_filter to trace_probe_event
and link it once on each event instead of each probe.

Link: http://lkml.kernel.org/r/157862073931.1800.3800576241181489174.stgit@devnote2

Cc: Jiri Olsa 
Cc: Peter Zijlstra 
Cc: Ingo Molnar 
Cc: "Naveen N . Rao" 
Cc: Anil S Keshavamurthy 
Cc: "David S . Miller" 
Cc: Namhyung Kim 
Cc: =?utf-8?q?Toke_H=C3=B8iland-J?= =?utf-8?b?w7hyZ2Vuc2Vu?= 
Cc: Jean-Tsung Hsiao 
Cc: Jesper Dangaard Brouer 
Cc: stable@vger.kernel.org
Fixes: 60d53e2c3b75 ("tracing/probe: Split trace_event related data from trace_probe")
Link: https://lkml.kernel.org/r/20200108171611.GA8472@kernel.org
Reported-by: Arnaldo Carvalho de Melo 
Tested-by: Arnaldo Carvalho de Melo 
Signed-off-by: Masami Hiramatsu 
Signed-off-by: Steven Rostedt (VMware)

tracing/probe: Fix to check the difference of nr_args before adding probe

2019-09-28T21:07:53+00:00

Steven reported that a test triggered:

==================================================================
 BUG: KASAN: slab-out-of-bounds in trace_kprobe_create+0xa9e/0xe40
 Read of size 8 at addr ffff8880c4f25a48 by task ftracetest/4798

 CPU: 2 PID: 4798 Comm: ftracetest Not tainted 5.3.0-rc6-test+ #30
 Hardware name: Hewlett-Packard HP Compaq Pro 6300 SFF/339A, BIOS K01 v03.03 07/14/2016
 Call Trace:
  dump_stack+0x7c/0xc0
  ? trace_kprobe_create+0xa9e/0xe40
  print_address_description+0x6c/0x332
  ? trace_kprobe_create+0xa9e/0xe40
  ? trace_kprobe_create+0xa9e/0xe40
  __kasan_report.cold.6+0x1a/0x3b
  ? trace_kprobe_create+0xa9e/0xe40
  kasan_report+0xe/0x12
  trace_kprobe_create+0xa9e/0xe40
  ? print_kprobe_event+0x280/0x280
  ? match_held_lock+0x1b/0x240
  ? find_held_lock+0xac/0xd0
  ? fs_reclaim_release.part.112+0x5/0x20
  ? lock_downgrade+0x350/0x350
  ? kasan_unpoison_shadow+0x30/0x40
  ? __kasan_kmalloc.constprop.6+0xc1/0xd0
  ? trace_kprobe_create+0xe40/0xe40
  ? trace_kprobe_create+0xe40/0xe40
  create_or_delete_trace_kprobe+0x2e/0x60
  trace_run_command+0xc3/0xe0
  ? trace_panic_handler+0x20/0x20
  ? kasan_unpoison_shadow+0x30/0x40
  trace_parse_run_command+0xdc/0x163
  vfs_write+0xe1/0x240
  ksys_write+0xba/0x150
  ? __ia32_sys_read+0x50/0x50
  ? tracer_hardirqs_on+0x61/0x180
  ? trace_hardirqs_off_caller+0x43/0x110
  ? mark_held_locks+0x29/0xa0
  ? do_syscall_64+0x14/0x260
  do_syscall_64+0x68/0x260

Fix to check the difference of nr_args before adding probe
on existing probes. This also may set the error log index
bigger than the number of command parameters. In that case
it sets the error position is next to the last parameter.

Link: http://lkml.kernel.org/r/156966474783.3478.13217501608215769150.stgit@devnote2

Fixes: ca89bc071d5e ("tracing/kprobe: Add multi-probe per event support")
Reported-by: Steven Rostedt (VMware) 
Signed-off-by: Masami Hiramatsu 
Signed-off-by: Steven Rostedt (VMware)