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
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acpi	…
asm-generic	…
clocksource	…
crypto	crypto: api - Use work queue in crypto_destroy_instance	2023-09-13 09:42:32 +02:00
drm	…
dt-bindings	dt-bindings: clock: qcom,gcc-sc8280xp: Add missing GDSCs	2023-09-13 09:42:45 +02:00
keys	…
kunit	…
kvm	…
linux	perf: Disallow mis-matched inherited group reads	2023-10-25 12:03:15 +02:00
math-emu	…
media	media: cec: core: add adap_unconfigured() callback	2023-09-13 09:42:54 +02:00
memory	…
misc	…
net	tcp: allow again tcp_disconnect() when threads are waiting	2023-10-25 12:03:12 +02:00
pcmcia	…
ras	…
rdma	…
rv	…
scsi	scsi: Do not attempt to rescan suspended devices	2023-10-10 22:00:35 +02:00
soc	…
sound	…
target	…
trace	neighbor: tracing: Move pin6 inside CONFIG_IPV6=y section	2023-10-25 12:03:07 +02:00
uapi	netlink: remove the flex array from struct nlmsghdr	2023-10-10 22:00:46 +02:00
ufs	…
vdso	…
video	…
xen	…