linux-toradex.git/kernel/trace/trace_kprobe.c, branch v6.16-rc6

tracing: probes: Fix a possible race in trace_probe_log APIs

2025-05-13T13:23:34+00:00

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)

Merge tag 'modules-6.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/modules/linux

2025-03-30T22:44:36+00:00

Pull modules updates from Petr Pavlu:

 - Use RCU instead of RCU-sched

   The mix of rcu_read_lock(), rcu_read_lock_sched() and
   preempt_disable() in the module code and its users has
   been replaced with just rcu_read_lock()

 - The rest of changes are smaller fixes and updates

* tag 'modules-6.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/modules/linux: (32 commits)
  MAINTAINERS: Update the MODULE SUPPORT section
  module: Remove unnecessary size argument when calling strscpy()
  module: Replace deprecated strncpy() with strscpy()
  params: Annotate struct module_param_attrs with __counted_by()
  bug: Use RCU instead RCU-sched to protect module_bug_list.
  static_call: Use RCU in all users of __module_text_address().
  kprobes: Use RCU in all users of __module_text_address().
  bpf: Use RCU in all users of __module_text_address().
  jump_label: Use RCU in all users of __module_text_address().
  jump_label: Use RCU in all users of __module_address().
  x86: Use RCU in all users of __module_address().
  cfi: Use RCU while invoking __module_address().
  powerpc/ftrace: Use RCU in all users of __module_text_address().
  LoongArch: ftrace: Use RCU in all users of __module_text_address().
  LoongArch/orc: Use RCU in all users of __module_address().
  arm64: module: Use RCU in all users of __module_text_address().
  ARM: module: Use RCU in all users of __module_text_address().
  module: Use RCU in all users of __module_text_address().
  module: Use RCU in all users of __module_address().
  module: Use RCU in search_module_extables().
  ...

tracing: probe-events: Log error for exceeding the number of arguments

2025-03-27T12:19:54+00:00

Add error message when the number of arguments exceeds the limitation.

Link: https://lore.kernel.org/all/174055075075.4079315.10916648136898316476.stgit@mhiramat.tok.corp.google.com/

Signed-off-by: Masami Hiramatsu (Google) 
Reviewed-by: Steven Rostedt (Google)

module: Use RCU in find_module_all().

2025-03-10T10:54:44+00:00

The modules list and module::kallsyms can be accessed under RCU
assumption.

Remove module_assert_mutex_or_preempt() from find_module_all() so it can
be used under RCU protection without warnings. Update its callers to use
RCU protection instead of preempt_disable().

Cc: Jiri Kosina 
Cc: Joe Lawrence 
Cc: Josh Poimboeuf 
Cc: Masami Hiramatsu 
Cc: Mathieu Desnoyers 
Cc: Miroslav Benes 
Cc: Petr Mladek 
Cc: Steven Rostedt 
Cc: linux-trace-kernel@vger.kernel.org
Cc: live-patching@vger.kernel.org
Signed-off-by: Sebastian Andrzej Siewior 
Acked-by: Peter Zijlstra (Intel) 
Reviewed-by: Petr Mladek 
Link: https://lore.kernel.org/r/20250108090457.512198-7-bigeasy@linutronix.de
Signed-off-by: Petr Pavlu

tracing/kprobes: Simplify __trace_kprobe_create() by removing gotos

2025-01-10T00:01:14+00:00

Simplify __trace_kprobe_create() by removing gotos.

Link: https://lore.kernel.org/all/173643301102.1514810.6149004416601259466.stgit@devnote2/

Signed-off-by: Masami Hiramatsu (Google) 
Reviewed-by: Steven Rostedt (Google)

tracing: Use __free() for kprobe events to cleanup

2025-01-10T00:01:01+00:00

Use __free() in trace_kprobe.c to cleanup code.

Link: https://lore.kernel.org/all/173643299989.1514810.2924926552980462072.stgit@devnote2/

Signed-off-by: Masami Hiramatsu (Google) 
Reviewed-by: Steven Rostedt (Google)

tracing/kprobe: Adopt guard() and scoped_guard()

2025-01-10T00:00:12+00:00

Use guard() or scoped_guard() in kprobe events for critical sections
rather than discrete lock/unlock pairs.

Link: https://lore.kernel.org/all/173289888883.73724.6586200652276577583.stgit@devnote2/

Signed-off-by: Masami Hiramatsu (Google)

tracing/kprobes: Fix to free objects when failed to copy a symbol

2025-01-09T23:57:18+00:00

In __trace_kprobe_create(), if something fails it must goto error block
to free objects. But when strdup() a symbol, it returns without that.
Fix it to goto the error block to free objects correctly.

Link: https://lore.kernel.org/all/173643297743.1514810.2408159540454241947.stgit@devnote2/

Fixes: 6212dd29683e ("tracing/kprobes: Use dyn_event framework for kprobe events")
Signed-off-by: Masami Hiramatsu (Google) 
Reviewed-by: Steven Rostedt (Google)

tracing/kprobe: Make trace_kprobe's module callback called after jump_label update

2024-12-23T15:08:13+00:00

Make sure the trace_kprobe's module notifer callback function is called
after jump_label's callback is called. Since the trace_kprobe's callback
eventually checks jump_label address during registering new kprobe on
the loading module, jump_label must be updated before this registration
happens.

Link: https://lore.kernel.org/all/173387585556.995044.3157941002975446119.stgit@devnote2/

Fixes: 614243181050 ("tracing/kprobes: Support module init function probing")
Signed-off-by: Masami Hiramatsu (Google)

tracing/probes: Fix MAX_TRACE_ARGS limit handling

2024-10-23T08:24:44+00:00

When creating a trace_probe we would set nr_args prior to truncating the
arguments to MAX_TRACE_ARGS. However, we would only initialize arguments
up to the limit.

This caused invalid memory access when attempting to set up probes with
more than 128 fetchargs.

  BUG: kernel NULL pointer dereference, address: 0000000000000020
  #PF: supervisor read access in kernel mode
  #PF: error_code(0x0000) - not-present page
  PGD 0 P4D 0
  Oops: Oops: 0000 [#1] PREEMPT SMP PTI
  CPU: 0 UID: 0 PID: 1769 Comm: cat Not tainted 6.11.0-rc7+ #8
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-1.fc39 04/01/2014
  RIP: 0010:__set_print_fmt+0x134/0x330

Resolve the issue by applying the MAX_TRACE_ARGS limit earlier. Return
an error when there are too many arguments instead of silently
truncating.

Link: https://lore.kernel.org/all/20240930202656.292869-1-mikel@mikelr.com/

Fixes: 035ba76014c0 ("tracing/probes: cleanup: Set trace_probe::nr_args at trace_probe_init")
Signed-off-by: Mikel Rychliski 
Signed-off-by: Masami Hiramatsu (Google)