tree 4fa2965d148c3e7ea456ab889d278d5c16d25d17
parent da3fd1a0010ccc9fe6fd5ae2b9e85e1aacc03e4d
author Peter Zijlstra <a.p.zijlstra@chello.nl> 1275556880 +0200
committer Ingo Molnar <mingo@elte.hu> 1275577388 +0200

perf: Fix crash in swevents

Frederic reported that because swevents handling doesn't disable IRQs
anymore, we can get a recursion of perf_adjust_period(), once from
overflow handling and once from the tick.

If both call ->disable, we get a double hlist_del_rcu() and trigger
a LIST_POISON2 dereference.

Since we don't actually need to stop/start a swevent to re-programm
the hardware (lack of hardware to program), simply nop out these
callbacks for the swevent pmu.

Reported-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1275557609.27810.35218.camel@twins>
Signed-off-by: Ingo Molnar <mingo@elte.hu>