]> git.ipfire.org Git - people/arne_f/kernel.git/commit
ARM: 7809/1: perf: fix event validation for software group leaders
authorWill Deacon <will.deacon@arm.com>
Wed, 7 Aug 2013 22:39:41 +0000 (23:39 +0100)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Tue, 20 Aug 2013 15:43:05 +0000 (08:43 -0700)
commit859325460d2b15ef9b78b55eff72d766e1b8ea29
tree1e7b208fc5e229f39a6d0f34994d7907defb9aa9
parent8e220cfd1a9f6c763a108a3b964a888fe341dabd
ARM: 7809/1: perf: fix event validation for software group leaders

commit c95eb3184ea1a3a2551df57190c81da695e2144b upstream.

It is possible to construct an event group with a software event as a
group leader and then subsequently add a hardware event to the group.
This results in the event group being validated by adding all members
of the group to a fake PMU and attempting to allocate each event on
their respective PMU.

Unfortunately, for software events wthout a corresponding arm_pmu, this
results in a kernel crash attempting to dereference the ->get_event_idx
function pointer.

This patch fixes the problem by checking explicitly for software events
and ignoring those in event validation (since they can always be
scheduled). We will probably want to revisit this for 3.12, since the
validation checks don't appear to work correctly when dealing with
multiple hardware PMUs anyway.

Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Tested-by: Vince Weaver <vincent.weaver@maine.edu>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
arch/arm/kernel/perf_event.c