Commit 43fa1adb authored Oct 02, 2006 by Eric W. Biederman Committed by Linus Torvalds Oct 02, 2006

[PATCH] file: Add locking to f_getown



This has been needed for a long time, but now with the advent of a
reference counted struct pid there are real consequences for getting this
wrong.

Someone I think it was Oleg Nesterov pointed out that this construct was
missing locking, when I introduced struct pid.  After taking time to review
the locking construct already present I figured out which lock needs to be
taken.  The other paths that access f_owner.pid take either the f_owner
read or the write lock.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

parent a03fcb73

fs/fcntl.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -305,9 +305,11 @@ void f_delown(struct file *filp)
		pid_t f_getown(struct file *filp)
		{
		pid_t pid;
		read_lock(&filp->f_owner.lock);
		pid = pid_nr(filp->f_owner.pid);
		if (filp->f_owner.pid_type == PIDTYPE_PGID)
		pid = -pid;
		read_unlock(&filp->f_owner.lock);
		return pid;
		}

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