linux.git/kernel/trace/trace_eprobe.c, branch v6.1.168

tracing/eprobe: Fix to release eprobe when failed to add dyn_event

2024-12-14T18:54:50+00:00

[ Upstream commit 494b332064c0ce2f7392fa92632bc50191c1b517 ]

Fix eprobe event to unregister event call and release eprobe when it fails
to add dynamic event correctly.

Link: https://lore.kernel.org/all/173289886698.73724.1959899350183686006.stgit@devnote2/

Fixes: 7491e2c44278 ("tracing: Add a probe that attaches to trace events")
Signed-off-by: Masami Hiramatsu (Google) 
Signed-off-by: Sasha Levin

kernel/trace: Fix cleanup logic of enable_trace_eprobe

2023-07-23T11:49:24+00:00

[ Upstream commit cf0a624dc706c306294c14e6b3e7694702f25191 ]

The enable_trace_eprobe() function enables all event probes, attached
to given trace probe. If an error occurs in enabling one of the event
probes, all others should be roll backed. There is a bug in that roll
back logic - instead of all event probes, only the failed one is
disabled.

Link: https://lore.kernel.org/all/20230703042853.1427493-1-tz.stoyanov@gmail.com/

Reported-by: Dan Carpenter 
Fixes: 7491e2c44278 ("tracing: Add a probe that attaches to trace events")
Signed-off-by: Tzvetomir Stoyanov (VMware) 
Acked-by: Masami Hiramatsu (Google) 
Reviewed-by: Steven Rostedt (Google) 
Signed-off-by: Masami Hiramatsu (Google) 
Signed-off-by: Sasha Levin

tracing: Fix race where eprobes can be called before the event

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

commit d5f30a7da8ea8e6450250275cec5670cee3c4264 upstream.

The flag that tells the event to call its triggers after reading the event
is set for eprobes after the eprobe is enabled. This leads to a race where
the eprobe may be triggered at the beginning of the event where the record
information is NULL. The eprobe then dereferences the NULL record causing
a NULL kernel pointer bug.

Test for a NULL record to keep this from happening.

Link: https://lore.kernel.org/linux-trace-kernel/20221116192552.1066630-1-rafaelmendsr@gmail.com/
Link: https://lore.kernel.org/all/20221117214249.2addbe10@gandalf.local.home/

Cc: stable@vger.kernel.org
Fixes: 7491e2c442781 ("tracing: Add a probe that attaches to trace events")
Reported-by: Rafael Mendonca 
Signed-off-by: Steven Rostedt (Google) 
Acked-by: Masami Hiramatsu (Google) 
Signed-off-by: Masami Hiramatsu (Google) 
Signed-off-by: Greg Kroah-Hartman

Merge tag 'trace-probes-v6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

2022-11-20T23:31:20+00:00

Pull tracing/probes fixes from Steven Rostedt:

 - Fix possible NULL pointer dereference on trace_event_file in
   kprobe_event_gen_test_exit()

 - Fix NULL pointer dereference for trace_array in
   kprobe_event_gen_test_exit()

 - Fix memory leak of filter string for eprobes

 - Fix a possible memory leak in rethook_alloc()

 - Skip clearing aggrprobe's post_handler in kprobe-on-ftrace case which
   can cause a possible use-after-free

 - Fix warning in eprobe filter creation

 - Fix eprobe filter creation as it picked the wrong event for the
   fields

* tag 'trace-probes-v6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  tracing/eprobe: Fix eprobe filter to make a filter correctly
  tracing/eprobe: Fix warning in filter creation
  kprobes: Skip clearing aggrprobe's post_handler in kprobe-on-ftrace case
  rethook: fix a potential memleak in rethook_alloc()
  tracing/eprobe: Fix memory leak of filter string
  tracing: kprobe: Fix potential null-ptr-deref on trace_array in kprobe_event_gen_test_exit()
  tracing: kprobe: Fix potential null-ptr-deref on trace_event_file in kprobe_event_gen_test_exit()

tracing: Fix race where eprobes can be called before the event

2022-11-20T19:05:50+00:00

The flag that tells the event to call its triggers after reading the event
is set for eprobes after the eprobe is enabled. This leads to a race where
the eprobe may be triggered at the beginning of the event where the record
information is NULL. The eprobe then dereferences the NULL record causing
a NULL kernel pointer bug.

Test for a NULL record to keep this from happening.

Link: https://lore.kernel.org/linux-trace-kernel/20221116192552.1066630-1-rafaelmendsr@gmail.com/
Link: https://lore.kernel.org/linux-trace-kernel/20221117214249.2addbe10@gandalf.local.home

Cc: Linux Trace Kernel 
Cc: Tzvetomir Stoyanov 
Cc: Tom Zanussi 
Cc: stable@vger.kernel.org
Fixes: 7491e2c442781 ("tracing: Add a probe that attaches to trace events")
Acked-by: Masami Hiramatsu (Google) 
Reported-by: Rafael Mendonca 
Signed-off-by: Steven Rostedt (Google)

tracing/eprobe: Fix eprobe filter to make a filter correctly

2022-11-18T01:15:34+00:00

Since the eprobe filter was defined based on the eprobe's trace event
itself, it doesn't work correctly. Use the original trace event of
the eprobe when making the filter so that the filter works correctly.

Without this fix:

 # echo 'e syscalls/sys_enter_openat \
	flags_rename=$flags:u32 if flags < 1000' >> dynamic_events
 # echo 1 > events/eprobes/sys_enter_openat/enable
[  114.551550] event trace: Could not enable event sys_enter_openat
-bash: echo: write error: Invalid argument

With this fix:
 # echo 'e syscalls/sys_enter_openat \
	flags_rename=$flags:u32 if flags < 1000' >> dynamic_events
 # echo 1 > events/eprobes/sys_enter_openat/enable
 # tail trace
cat-241     [000] ...1.   266.498449: sys_enter_openat: (syscalls.sys_enter_openat) flags_rename=0
cat-242     [000] ...1.   266.977640: sys_enter_openat: (syscalls.sys_enter_openat) flags_rename=0

Link: https://lore.kernel.org/all/166823166395.1385292.8931770640212414483.stgit@devnote3/

Fixes: 752be5c5c910 ("tracing/eprobe: Add eprobe filter support")
Reported-by: Rafael Mendonca 
Tested-by: Rafael Mendonca 
Signed-off-by: Masami Hiramatsu (Google)

tracing/eprobe: Fix warning in filter creation

2022-11-18T01:15:34+00:00

The filter pointer (filterp) passed to create_filter() function must be a
pointer that references a NULL pointer, otherwise, we get a warning when
adding a filter option to the event probe:

root@localhost:/sys/kernel/tracing# echo 'e:egroup/stat_runtime_4core sched/sched_stat_runtime \
        runtime=$runtime:u32 if cpu < 4' >> dynamic_events
[ 5034.340439] ------------[ cut here ]------------
[ 5034.341258] WARNING: CPU: 0 PID: 223 at kernel/trace/trace_events_filter.c:1939 create_filter+0x1db/0x250
[...] stripped
[ 5034.345518] RIP: 0010:create_filter+0x1db/0x250
[...] stripped
[ 5034.351604] Call Trace:
[ 5034.351803]  
[ 5034.351959]  ? process_preds+0x1b40/0x1b40
[ 5034.352241]  ? rcu_read_lock_bh_held+0xd0/0xd0
[ 5034.352604]  ? kasan_set_track+0x29/0x40
[ 5034.352904]  ? kasan_save_alloc_info+0x1f/0x30
[ 5034.353264]  create_event_filter+0x38/0x50
[ 5034.353573]  __trace_eprobe_create+0x16f4/0x1d20
[ 5034.353964]  ? eprobe_dyn_event_release+0x360/0x360
[ 5034.354363]  ? mark_held_locks+0xa6/0xf0
[ 5034.354684]  ? _raw_spin_unlock_irqrestore+0x35/0x60
[ 5034.355105]  ? trace_hardirqs_on+0x41/0x120
[ 5034.355417]  ? _raw_spin_unlock_irqrestore+0x35/0x60
[ 5034.355751]  ? __create_object+0x5b7/0xcf0
[ 5034.356027]  ? lock_is_held_type+0xaf/0x120
[ 5034.356362]  ? rcu_read_lock_bh_held+0xb0/0xd0
[ 5034.356716]  ? rcu_read_lock_bh_held+0xd0/0xd0
[ 5034.357084]  ? kasan_set_track+0x29/0x40
[ 5034.357411]  ? kasan_save_alloc_info+0x1f/0x30
[ 5034.357715]  ? __kasan_kmalloc+0xb8/0xc0
[ 5034.357985]  ? write_comp_data+0x2f/0x90
[ 5034.358302]  ? __sanitizer_cov_trace_pc+0x25/0x60
[ 5034.358691]  ? argv_split+0x381/0x460
[ 5034.358949]  ? write_comp_data+0x2f/0x90
[ 5034.359240]  ? eprobe_dyn_event_release+0x360/0x360
[ 5034.359620]  trace_probe_create+0xf6/0x110
[ 5034.359940]  ? trace_probe_match_command_args+0x240/0x240
[ 5034.360376]  eprobe_dyn_event_create+0x21/0x30
[ 5034.360709]  create_dyn_event+0xf3/0x1a0
[ 5034.360983]  trace_parse_run_command+0x1a9/0x2e0
[ 5034.361297]  ? dyn_event_release+0x500/0x500
[ 5034.361591]  dyn_event_write+0x39/0x50
[ 5034.361851]  vfs_write+0x311/0xe50
[ 5034.362091]  ? dyn_event_seq_next+0x40/0x40
[ 5034.362376]  ? kernel_write+0x5b0/0x5b0
[ 5034.362637]  ? write_comp_data+0x2f/0x90
[ 5034.362937]  ? __sanitizer_cov_trace_pc+0x25/0x60
[ 5034.363258]  ? ftrace_syscall_enter+0x544/0x840
[ 5034.363563]  ? write_comp_data+0x2f/0x90
[ 5034.363837]  ? __sanitizer_cov_trace_pc+0x25/0x60
[ 5034.364156]  ? write_comp_data+0x2f/0x90
[ 5034.364468]  ? write_comp_data+0x2f/0x90
[ 5034.364770]  ksys_write+0x158/0x2a0
[ 5034.365022]  ? __ia32_sys_read+0xc0/0xc0
[ 5034.365344]  __x64_sys_write+0x7c/0xc0
[ 5034.365669]  ? syscall_enter_from_user_mode+0x53/0x70
[ 5034.366084]  do_syscall_64+0x60/0x90
[ 5034.366356]  entry_SYSCALL_64_after_hwframe+0x63/0xcd
[ 5034.366767] RIP: 0033:0x7ff0b43938f3
[...] stripped
[ 5034.371892]  
[ 5034.374720] ---[ end trace 0000000000000000 ]---

Link: https://lore.kernel.org/all/20221108202148.1020111-1-rafaelmendsr@gmail.com/

Fixes: 752be5c5c910 ("tracing/eprobe: Add eprobe filter support")
Signed-off-by: Rafael Mendonca 
Acked-by: Masami Hiramatsu (Google) 
Signed-off-by: Masami Hiramatsu (Google)

tracing/eprobe: Fix memory leak of filter string

2022-11-18T01:15:34+00:00

The filter string doesn't get freed when a dynamic event is deleted. If a
filter is set, then memory is leaked:

root@localhost:/sys/kernel/tracing# echo 'e:egroup/stat_runtime_4core \
        sched/sched_stat_runtime runtime=$runtime:u32 if cpu < 4' >> dynamic_events
root@localhost:/sys/kernel/tracing# echo "-:egroup/stat_runtime_4core"  >> dynamic_events
root@localhost:/sys/kernel/tracing# echo scan > /sys/kernel/debug/kmemleak
[  224.416373] kmemleak: 1 new suspected memory leaks (see /sys/kernel/debug/kmemleak)
root@localhost:/sys/kernel/tracing# cat /sys/kernel/debug/kmemleak
unreferenced object 0xffff88810156f1b8 (size 8):
  comm "bash", pid 224, jiffies 4294935612 (age 55.800s)
  hex dump (first 8 bytes):
    63 70 75 20 3c 20 34 00                          cpu < 4.
  backtrace:
    [<000000009f880725>] __kmem_cache_alloc_node+0x18e/0x720
    [<0000000042492946>] __kmalloc+0x57/0x240
    [<0000000034ea7995>] __trace_eprobe_create+0x1214/0x1d30
    [<00000000d70ef730>] trace_probe_create+0xf6/0x110
    [<00000000915c7b16>] eprobe_dyn_event_create+0x21/0x30
    [<000000000d894386>] create_dyn_event+0xf3/0x1a0
    [<00000000e9af57d5>] trace_parse_run_command+0x1a9/0x2e0
    [<0000000080777f18>] dyn_event_write+0x39/0x50
    [<0000000089f0ec73>] vfs_write+0x311/0xe50
    [<000000003da1bdda>] ksys_write+0x158/0x2a0
    [<00000000bb1e616e>] __x64_sys_write+0x7c/0xc0
    [<00000000e8aef1f7>] do_syscall_64+0x60/0x90
    [<00000000fe7fe8ba>] entry_SYSCALL_64_after_hwframe+0x63/0xcd

Additionally, in __trace_eprobe_create() function, if an error occurs after
the call to trace_eprobe_parse_filter(), which allocates the filter string,
then memory is also leaked. That can be reproduced by creating the same
event probe twice:

root@localhost:/sys/kernel/tracing# echo 'e:egroup/stat_runtime_4core \
        sched/sched_stat_runtime runtime=$runtime:u32 if cpu < 4' >> dynamic_events
root@localhost:/sys/kernel/tracing# echo 'e:egroup/stat_runtime_4core \
        sched/sched_stat_runtime runtime=$runtime:u32 if cpu < 4' >> dynamic_events
-bash: echo: write error: File exists
root@localhost:/sys/kernel/tracing# echo scan > /sys/kernel/debug/kmemleak
[  207.871584] kmemleak: 1 new suspected memory leaks (see /sys/kernel/debug/kmemleak)
root@localhost:/sys/kernel/tracing# cat /sys/kernel/debug/kmemleak
unreferenced object 0xffff8881020d17a8 (size 8):
  comm "bash", pid 223, jiffies 4294938308 (age 31.000s)
  hex dump (first 8 bytes):
    63 70 75 20 3c 20 34 00                          cpu < 4.
  backtrace:
    [<000000000e4f5f31>] __kmem_cache_alloc_node+0x18e/0x720
    [<0000000024f0534b>] __kmalloc+0x57/0x240
    [<000000002930a28e>] __trace_eprobe_create+0x1214/0x1d30
    [<0000000028387903>] trace_probe_create+0xf6/0x110
    [<00000000a80d6a9f>] eprobe_dyn_event_create+0x21/0x30
    [<000000007168698c>] create_dyn_event+0xf3/0x1a0
    [<00000000f036bf6a>] trace_parse_run_command+0x1a9/0x2e0
    [<00000000014bde8b>] dyn_event_write+0x39/0x50
    [<0000000078a097f7>] vfs_write+0x311/0xe50
    [<00000000996cb208>] ksys_write+0x158/0x2a0
    [<00000000a3c2acb0>] __x64_sys_write+0x7c/0xc0
    [<0000000006b5d698>] do_syscall_64+0x60/0x90
    [<00000000780e8ecf>] entry_SYSCALL_64_after_hwframe+0x63/0xcd

Fix both issues by releasing the filter string in
trace_event_probe_cleanup().

Link: https://lore.kernel.org/all/20221108235738.1021467-1-rafaelmendsr@gmail.com/

Fixes: 752be5c5c910 ("tracing/eprobe: Add eprobe filter support")
Signed-off-by: Rafael Mendonca 
Acked-by: Masami Hiramatsu (Google) 
Signed-off-by: Masami Hiramatsu (Google)

tracing: Move duplicate code of trace_kprobe/eprobe.c into header

2022-10-12T17:50:00+00:00

The functions:

  fetch_store_strlen_user()
  fetch_store_strlen()
  fetch_store_string_user()
  fetch_store_string()

are identical in both trace_kprobe.c and trace_eprobe.c. Move them into
a new header file trace_probe_kernel.h to share it. This code will later
be used by the synthetic events as well.

Marked for stable as a fix for a crash in synthetic events requires it.

Link: https://lkml.kernel.org/r/20221012104534.467668078@goodmis.org

Cc: stable@vger.kernel.org
Cc: Andrew Morton 
Cc: Tom Zanussi 
Acked-by: Masami Hiramatsu (Google) 
Reviewed-by: Tom Zanussi 
Fixes: bd82631d7ccdc ("tracing: Add support for dynamic strings to synthetic events")
Signed-off-by: Steven Rostedt (Google)

tracing/eprobe: Fix alloc event dir failed when event name no set

2022-09-27T18:48:26+00:00

The event dir will alloc failed when event name no set, using the
command:
"echo "e:esys/ syscalls/sys_enter_openat file=\$filename:string"
>> dynamic_events"
It seems that dir name="syscalls/sys_enter_openat" is not allowed
in debugfs. So just use the "sys_enter_openat" as the event name.

Link: https://lkml.kernel.org/r/1664028814-45923-1-git-send-email-chentao.kernel@linux.alibaba.com

Cc: Ingo Molnar 
Cc: Tom Zanussi 
Cc: Linyu Yuan 
Cc: Tao Chen 
Signed-off-by: Tao Chen 
Signed-off-by: Steven Rostedt (Google)