Peter Zijlstra f6952655a6 perf: Disallow mis-matched inherited group reads ... commit 32671e3799 upstream. Because group consistency is non-atomic between parent (filedesc) and children (inherited) events, it is possible for PERF_FORMAT_GROUP read() to try and sum non-matching counter groups -- with non-sensical results. Add group_generation to distinguish the case where a parent group removes and adds an event and thus has the same number, but a different configuration of events as inherited groups. This became a problem when commit fa8c269353 ("perf/core: Invert perf_read_group() loops") flipped the order of child_list and sibling_list. Previously it would iterate the group (sibling_list) first, and for each sibling traverse the child_list. In this order, only the group composition of the parent is relevant. By flipping the order the group composition of the child (inherited) events becomes an issue and the mis-match in group composition becomes evident. That said; even prior to this commit, while reading of a group that is not equally inherited was not broken, it still made no sense. (Ab)use ECHILD as error return to indicate issues with child process group composition. Fixes: fa8c269353 ("perf/core: Invert perf_read_group() loops") Reported-by: Budimir Markovic <markovicbudimir@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20231018115654.GK33217@noisy.programming.kicks-ass.net Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2023-10-25 12:03:15 +02:00
..
callchain.c	uaccess: remove CONFIG_SET_FS	2022-02-25 09:36:06 +01:00
core.c	perf: Disallow mis-matched inherited group reads	2023-10-25 12:03:15 +02:00
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: Fix missing SIGTRAPs	2022-10-17 16:32:05 +02:00
uprobes.c	mm/madvise: add file and shmem support to MADV_COLLAPSE	2022-10-03 14:03:33 -07:00