Commit 76518d37 authored by Bernd Edlinger's avatar Bernd Edlinger Committed by Eric W. Biederman
Browse files

proc: io_accounting: Use new infrastructure to fix deadlocks in execve 



This changes do_io_accounting to use the new exec_update_mutex
instead of cred_guard_mutex.

This fixes possible deadlocks when the trace is accessing
/proc/$pid/io for instance.

This should be safe, as the credentials are only used for reading.

Signed-off-by: default avatarBernd Edlinger <bernd.edlinger@hotmail.de>
Signed-off-by: default avatarEric W. Biederman <ebiederm@xmission.com>
parent 2db9dbf7

fs/proc/base.c

+2 −2
Original line number Diff line number Diff line
@@ -2883,7 +2883,7 @@ static int do_io_accounting(struct task_struct *task, struct seq_file *m, int wh 
	unsigned long flags;

	int result;



	result = mutex_lock_killable(&task->signal->cred_guard_mutex);

	result = mutex_lock_killable(&task->signal->exec_update_mutex);

	if (result)

		return result;
@@ -2919,7 +2919,7 @@ static int do_io_accounting(struct task_struct *task, struct seq_file *m, int wh 
	result = 0;



out_unlock:

	mutex_unlock(&task->signal->cred_guard_mutex);

	mutex_unlock(&task->signal->exec_update_mutex);

	return result;

}

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