Mark Rutland 404902216b 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 15:41:23 +01:00
..
callchain.c
core.c	perf: Fix perf_event_validate_size() lockdep splat	2023-12-20 15:41:23 +01:00
hw_breakpoint.c	perf/hw_breakpoint: Fix arch_hw_breakpoint use-before-initialization	2019-09-06 08:24:01 +02:00
internal.h	perf: Fix get_recursion_context()	2020-11-18 19:20:28 +01:00
Makefile
ring_buffer.c	perf/core: Add a new read format to get a number of lost samples	2023-12-13 18:18:15 +01:00
uprobes.c	treewide: Remove uninitialized_var() usage	2023-06-09 10:29:01 +02:00