This changes lock_trace to use the new exec_update_mutex instead of cred_guard_mutex.
This fixes possible deadlocks when the trace is accessing /proc/$pid/stack for instance.
This should be safe, as the credentials are only used for reading, and task->mm is updated on execve under the new exec_update_mutex.
Signed-off-by: Bernd Edlinger bernd.edlinger@hotmail.de --- fs/proc/base.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/fs/proc/base.c b/fs/proc/base.c index ebea950..4fdfe4f 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -403,11 +403,11 @@ static int proc_pid_wchan(struct seq_file *m, struct pid_namespace *ns,
static int lock_trace(struct task_struct *task) { - int err = mutex_lock_killable(&task->signal->cred_guard_mutex); + int err = mutex_lock_killable(&task->signal->exec_update_mutex); if (err) return err; if (!ptrace_may_access(task, PTRACE_MODE_ATTACH_FSCREDS)) { - mutex_unlock(&task->signal->cred_guard_mutex); + mutex_unlock(&task->signal->exec_update_mutex); return -EPERM; } return 0; @@ -415,7 +415,7 @@ static int lock_trace(struct task_struct *task)
static void unlock_trace(struct task_struct *task) { - mutex_unlock(&task->signal->cred_guard_mutex); + mutex_unlock(&task->signal->exec_update_mutex); }
#ifdef CONFIG_STACKTRACE