Mark Rutland 557f7ad064 perf: Fix perf_event_validate_size() lockdep splat ... commit 7e2c1e4b34 upstream. When lockdep is enabled, the for_each_sibling_event(sibling, event) macro checks that event->ctx->mutex is held. When creating a new group leader event, we call perf_event_validate_size() on a partially initialized event where event->ctx is NULL, and so when for_each_sibling_event() attempts to check event->ctx->mutex, we get a splat, as reported by Lucas De Marchi: WARNING: CPU: 8 PID: 1471 at kernel/events/core.c:1950 __do_sys_perf_event_open+0xf37/0x1080 This only happens for a new event which is its own group_leader, and in this case there cannot be any sibling events. Thus it's safe to skip the check for siblings, which avoids having to make invasive and ugly changes to for_each_sibling_event(). Avoid the splat by bailing out early when the new event is its own group_leader. Fixes: 382c27f4ed ("perf: Fix perf_event_validate_size()") Closes: https://lore.kernel.org/lkml/20231214000620.3081018-1-lucas.demarchi@intel.com/ Closes: https://lore.kernel.org/lkml/ZXpm6gQ%2Fd59jGsuW@xpf.sh.intel.com/ Reported-by: Lucas De Marchi <lucas.demarchi@intel.com> Reported-by: Pengfei Xu <pengfei.xu@intel.com> Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20231215112450.3972309-1-mark.rutland@arm.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2023-12-20 17:00:24 +01:00
..
callchain.c	uaccess: remove CONFIG_SET_FS	2022-02-25 09:36:06 +01:00
core.c	perf: Fix perf_event_validate_size() lockdep splat	2023-12-20 17:00:24 +01:00
hw_breakpoint_test.c	perf/hw_breakpoint: test: Skip the test if dependencies unmet	2022-11-02 12:22:05 +01:00
hw_breakpoint.c	perf/hw_breakpoint: Annotate tsk->perf_event_mutex vs ctx->mutex	2022-10-04 13:32:09 +02:00
internal.h	perf/core: Fix perf_mmap fail when CONFIG_PERF_USE_VMALLOC enabled	2022-04-19 21:15:42 +02:00
Makefile	perf/hw_breakpoint: Add KUnit test for constraints accounting	2022-08-30 10:56:20 +02:00
ring_buffer.c	perf/core: Bail out early if the request AUX area is out of bound	2023-11-28 17:06:54 +00:00
uprobes.c	mm/madvise: add file and shmem support to MADV_COLLAPSE	2022-10-03 14:03:33 -07:00