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| author | Oleg Nesterov <oleg@redhat.com> | 2013-06-20 17:50:06 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2013-06-20 17:57:00 +0200 |
| commit | 8b4d801b2b123b6c09742f861fe44a8527b84d47 (patch) | |
| tree | 12f820394b663a494bc70d63307fad8589a497ef /kernel | |
| parent | 003002e04ed38618fc37b92ba128f5ca79d39f4f (diff) | |
| download | lwn-8b4d801b2b123b6c09742f861fe44a8527b84d47.tar.gz lwn-8b4d801b2b123b6c09742f861fe44a8527b84d47.zip | |
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')
| -rw-r--r-- | kernel/events/hw_breakpoint.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/events/hw_breakpoint.c b/kernel/events/hw_breakpoint.c index a64f8aeb5c1f..a853deabe6cf 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); } |