Commit cde8e88498c8de69271fcb6d4dd974979368fa67
Committed by
Ingo Molnar
Ingo Molnar
1 parent
b0b2072df3
Exists in
master
and in
7 other branches
perf: Sanitize the RCU logic
Simplify things and simply synchronize against two RCU variants for PMU unregister -- we don't care about performance, its module unload if anything. Reported-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Showing 1 changed file with 9 additions and 8 deletions Side-by-side Diff
kernel/perf_event.c
| ... | ... | @@ -3810,7 +3810,7 @@ |
| 3810 | 3810 | struct pmu *pmu; |
| 3811 | 3811 | int ctxn; |
| 3812 | 3812 | |
| 3813 | - rcu_read_lock_sched(); | |
| 3813 | + rcu_read_lock(); | |
| 3814 | 3814 | list_for_each_entry_rcu(pmu, &pmus, entry) { |
| 3815 | 3815 | cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); |
| 3816 | 3816 | perf_event_task_ctx(&cpuctx->ctx, task_event); |
| ... | ... | @@ -3825,7 +3825,7 @@ |
| 3825 | 3825 | if (ctx) |
| 3826 | 3826 | perf_event_task_ctx(ctx, task_event); |
| 3827 | 3827 | } |
| 3828 | - rcu_read_unlock_sched(); | |
| 3828 | + rcu_read_unlock(); | |
| 3829 | 3829 | } |
| 3830 | 3830 | |
| 3831 | 3831 | static void perf_event_task(struct task_struct *task, |
| ... | ... | @@ -3943,7 +3943,7 @@ |
| 3943 | 3943 | |
| 3944 | 3944 | comm_event->event_id.header.size = sizeof(comm_event->event_id) + size; |
| 3945 | 3945 | |
| 3946 | - rcu_read_lock_sched(); | |
| 3946 | + rcu_read_lock(); | |
| 3947 | 3947 | list_for_each_entry_rcu(pmu, &pmus, entry) { |
| 3948 | 3948 | cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); |
| 3949 | 3949 | perf_event_comm_ctx(&cpuctx->ctx, comm_event); |
| ... | ... | @@ -3956,7 +3956,7 @@ |
| 3956 | 3956 | if (ctx) |
| 3957 | 3957 | perf_event_comm_ctx(ctx, comm_event); |
| 3958 | 3958 | } |
| 3959 | - rcu_read_unlock_sched(); | |
| 3959 | + rcu_read_unlock(); | |
| 3960 | 3960 | } |
| 3961 | 3961 | |
| 3962 | 3962 | void perf_event_comm(struct task_struct *task) |
| ... | ... | @@ -4126,7 +4126,7 @@ |
| 4126 | 4126 | |
| 4127 | 4127 | mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size; |
| 4128 | 4128 | |
| 4129 | - rcu_read_lock_sched(); | |
| 4129 | + rcu_read_lock(); | |
| 4130 | 4130 | list_for_each_entry_rcu(pmu, &pmus, entry) { |
| 4131 | 4131 | cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); |
| 4132 | 4132 | perf_event_mmap_ctx(&cpuctx->ctx, mmap_event, |
| ... | ... | @@ -4142,7 +4142,7 @@ |
| 4142 | 4142 | vma->vm_flags & VM_EXEC); |
| 4143 | 4143 | } |
| 4144 | 4144 | } |
| 4145 | - rcu_read_unlock_sched(); | |
| 4145 | + rcu_read_unlock(); | |
| 4146 | 4146 | |
| 4147 | 4147 | kfree(buf); |
| 4148 | 4148 | } |
| 4149 | 4149 | |
| ... | ... | @@ -5218,10 +5218,11 @@ |
| 5218 | 5218 | mutex_unlock(&pmus_lock); |
| 5219 | 5219 | |
| 5220 | 5220 | /* |
| 5221 | - * We use the pmu list either under SRCU or preempt_disable, | |
| 5222 | - * synchronize_srcu() implies synchronize_sched() so we're good. | |
| 5221 | + * We dereference the pmu list under both SRCU and regular RCU, so | |
| 5222 | + * synchronize against both of those. | |
| 5223 | 5223 | */ |
| 5224 | 5224 | synchronize_srcu(&pmus_srcu); |
| 5225 | + synchronize_rcu(); | |
| 5225 | 5226 | |
| 5226 | 5227 | free_percpu(pmu->pmu_disable_count); |
| 5227 | 5228 | free_pmu_context(pmu->pmu_cpu_context); |