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authorBernd Edlinger2020-03-20 21:27:55 +0100
committerEric W. Biederman2020-03-25 10:04:01 -0500
commit6914303824bb572278568330d72fc1f8f9814e67 (patch)
tree30d432620d9068f7edb769d376816cf50433134c /kernel/events
parent76518d3798855242817e8a8ed76b2d72f4415624 (diff)
perf: Use new infrastructure to fix deadlocks in execve
This changes perf_event_set_clock to use the new exec_update_mutex instead of cred_guard_mutex. This should be safe, as the credentials are only used for reading. Signed-off-by: Bernd Edlinger <bernd.edlinger@hotmail.de> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Diffstat (limited to 'kernel/events')
-rw-r--r--kernel/events/core.c12
1 files changed, 6 insertions, 6 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c
index e453589da97c..71cba8cfccbc 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -1249,7 +1249,7 @@ static void put_ctx(struct perf_event_context *ctx)
* function.
*
* Lock order:
- * cred_guard_mutex
+ * exec_update_mutex
* task_struct::perf_event_mutex
* perf_event_context::mutex
* perf_event::child_mutex;
@@ -11263,14 +11263,14 @@ SYSCALL_DEFINE5(perf_event_open,
}
if (task) {
- err = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
+ err = mutex_lock_interruptible(&task->signal->exec_update_mutex);
if (err)
goto err_task;
/*
* Reuse ptrace permission checks for now.
*
- * We must hold cred_guard_mutex across this and any potential
+ * We must hold exec_update_mutex across this and any potential
* perf_install_in_context() call for this new event to
* serialize against exec() altering our credentials (and the
* perf_event_exit_task() that could imply).
@@ -11559,7 +11559,7 @@ SYSCALL_DEFINE5(perf_event_open,
mutex_unlock(&ctx->mutex);
if (task) {
- mutex_unlock(&task->signal->cred_guard_mutex);
+ mutex_unlock(&task->signal->exec_update_mutex);
put_task_struct(task);
}
@@ -11595,7 +11595,7 @@ err_alloc:
free_event(event);
err_cred:
if (task)
- mutex_unlock(&task->signal->cred_guard_mutex);
+ mutex_unlock(&task->signal->exec_update_mutex);
err_task:
if (task)
put_task_struct(task);
@@ -11900,7 +11900,7 @@ static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
/*
* When a child task exits, feed back event values to parent events.
*
- * Can be called with cred_guard_mutex held when called from
+ * Can be called with exec_update_mutex held when called from
* install_exec_creds().
*/
void perf_event_exit_task(struct task_struct *child)