Mark Rutland 7b427d8cb7 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 15:17:41 +01:00
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callchain.c	uaccess: add force_uaccess_{begin,end} helpers	2020-08-12 10:57:59 -07:00
core.c	perf: Fix perf_event_validate_size() lockdep splat	2023-12-20 15:17:41 +01:00
hw_breakpoint.c	perf/hw_breakpoint: Replace deprecated CPU-hotplug functions	2021-08-26 09:14:36 +02:00
internal.h	tracing/perf: Add interrupt_context_level() helper	2023-11-28 16:56:21 +00:00
Makefile	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
ring_buffer.c	perf/core: Add a new read format to get a number of lost samples	2023-12-13 18:36:47 +01:00
uprobes.c	Merge branch 'akpm' (patches from Andrew)	2021-06-29 17:29:11 -07:00