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-rw-r--r--kernel/perf_counter.c11
1 files changed, 5 insertions, 6 deletions
diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c
index 8d4f0dd41c2..adb6ae506d5 100644
--- a/kernel/perf_counter.c
+++ b/kernel/perf_counter.c
@@ -175,6 +175,11 @@ perf_lock_task_context(struct task_struct *task, unsigned long *flags)
spin_unlock_irqrestore(&ctx->lock, *flags);
goto retry;
}
+
+ if (!atomic_inc_not_zero(&ctx->refcount)) {
+ spin_unlock_irqrestore(&ctx->lock, *flags);
+ ctx = NULL;
+ }
}
rcu_read_unlock();
return ctx;
@@ -193,7 +198,6 @@ static struct perf_counter_context *perf_pin_task_context(struct task_struct *ta
ctx = perf_lock_task_context(task, &flags);
if (ctx) {
++ctx->pin_count;
- get_ctx(ctx);
spin_unlock_irqrestore(&ctx->lock, flags);
}
return ctx;
@@ -1459,11 +1463,6 @@ static struct perf_counter_context *find_get_context(pid_t pid, int cpu)
put_ctx(parent_ctx);
ctx->parent_ctx = NULL; /* no longer a clone */
}
- /*
- * Get an extra reference before dropping the lock so that
- * this context won't get freed if the task exits.
- */
- get_ctx(ctx);
spin_unlock_irqrestore(&ctx->lock, flags);
}