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authorOleg Nesterov <oleg@redhat.com>2013-06-20 17:50:06 +0200
committerIngo Molnar <mingo@kernel.org>2013-06-20 17:57:00 +0200
commit8b4d801b2b123b6c09742f861fe44a8527b84d47 (patch)
tree12f820394b663a494bc70d63307fad8589a497ef /kernel/events
parent003002e04ed38618fc37b92ba128f5ca79d39f4f (diff)
downloadvexpress-lsk-8b4d801b2b123b6c09742f861fe44a8527b84d47.tar.gz
hw_breakpoint: Fix cpu check in task_bp_pinned(cpu)
trinity fuzzer triggered WARN_ONCE("Can't find any breakpoint slot") in arch_install_hw_breakpoint() but the problem is not arch-specific. The problem is, task_bp_pinned(cpu) checks "cpu == iter->cpu" but this doesn't account the "all cpus" events with iter->cpu < 0. This means that, say, register_user_hw_breakpoint(tsk) can happily create the arbitrary number > HBP_NUM of breakpoints which can not be activated. toggle_bp_task_slot() is equally wrong by the same reason and nr_task_bp_pinned[] can have negative entries. Simple test: # perl -e 'sleep 1 while 1' & # perf record -e mem:0x10,mem:0x10,mem:0x10,mem:0x10,mem:0x10 -p `pidof perl` Before this patch this triggers the same problem/WARN_ON(), after the patch it correctly fails with -ENOSPC. Reported-by: Vince Weaver <vincent.weaver@maine.edu> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: <stable@vger.kernel.org> Link: http://lkml.kernel.org/r/20130620155006.GA6324@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/events')
-rw-r--r--kernel/events/hw_breakpoint.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/events/hw_breakpoint.c b/kernel/events/hw_breakpoint.c
index a64f8aeb5c1..a853deabe6c 100644
--- a/kernel/events/hw_breakpoint.c
+++ b/kernel/events/hw_breakpoint.c
@@ -120,7 +120,7 @@ static int task_bp_pinned(int cpu, struct perf_event *bp, enum bp_type_idx type)
list_for_each_entry(iter, &bp_task_head, hw.bp_list) {
if (iter->hw.bp_target == tsk &&
find_slot_idx(iter) == type &&
- cpu == iter->cpu)
+ (iter->cpu < 0 || cpu == iter->cpu))
count += hw_breakpoint_weight(iter);
}