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authorOleg Nesterov <oleg@redhat.com>2013-06-20 17:50:09 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-07-03 11:03:23 -0700
commite2652ea43028e5409c2fd2b585dc8388a6e75bd0 (patch)
tree08ce8347d42ad9be9f98b6c42b91bb9c33c31b8d
parent3ddc55287a4505a5634643fec8e02f887498ffc8 (diff)
hw_breakpoint: Use cpu_possible_mask in {reserve,release}_bp_slot()
commit c790b0ad23f427c7522ffed264706238c57c007e upstream. fetch_bp_busy_slots() and toggle_bp_slot() use for_each_online_cpu(), this is obviously wrong wrt cpu_up() or cpu_down(), we can over/under account the per-cpu numbers. For example: # echo 0 >> /sys/devices/system/cpu/cpu1/online # perf record -e mem:0x10 -p 1 & # echo 1 >> /sys/devices/system/cpu/cpu1/online # perf record -e mem:0x10,mem:0x10,mem:0x10,mem:0x10 -C1 -a & # taskset -p 0x2 1 triggers the same WARN_ONCE("Can't find any breakpoint slot") in arch_install_hw_breakpoint(). Reported-by: Vince Weaver <vincent.weaver@maine.edu> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Link: http://lkml.kernel.org/r/20130620155009.GA6327@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--kernel/events/hw_breakpoint.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/events/hw_breakpoint.c b/kernel/events/hw_breakpoint.c
index 086adf25a55e..d99cb4b0c1fc 100644
--- a/kernel/events/hw_breakpoint.c
+++ b/kernel/events/hw_breakpoint.c
@@ -147,7 +147,7 @@ fetch_bp_busy_slots(struct bp_busy_slots *slots, struct perf_event *bp,
return;
}
- for_each_online_cpu(cpu) {
+ for_each_possible_cpu(cpu) {
unsigned int nr;
nr = per_cpu(nr_cpu_bp_pinned[type], cpu);
@@ -233,7 +233,7 @@ toggle_bp_slot(struct perf_event *bp, bool enable, enum bp_type_idx type,
if (cpu >= 0) {
toggle_bp_task_slot(bp, cpu, enable, type, weight);
} else {
- for_each_online_cpu(cpu)
+ for_each_possible_cpu(cpu)
toggle_bp_task_slot(bp, cpu, enable, type, weight);
}