fnctl: f_modown should call write_lock_irqsave/restore

commit b04da8bfdfbbd79544cab2fadfdc12e87eb01600 upstream.

Commit 703625118069f9f8960d356676662d3db5a9d116 exposed that f_modown()
should call write_lock_irqsave instead of just write_lock_irq so that
because a caller could have a spinlock held and it would not be good to
renable interrupts.

Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Tavis Ormandy <taviso@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/fcntl.c b/fs/fcntl.c
index 97e01dc0d95fc4fe8464d729ce94d32b888b567d..5ef953e6f908ea2d6f68061310a106fd0179d15a 100644 (file)
--- a/fs/fcntl.c
+++ b/fs/fcntl.c
@@ -199,7 +199,9 @@ static int setfl(int fd, struct file * filp, unsigned long arg)
 static void f_modown(struct file *filp, struct pid *pid, enum pid_type type,
                      int force)
 {
-       write_lock_irq(&filp->f_owner.lock);
+       unsigned long flags;
+
+       write_lock_irqsave(&filp->f_owner.lock, flags);
        if (force || !filp->f_owner.pid) {
                put_pid(filp->f_owner.pid);
                filp->f_owner.pid = get_pid(pid);
@@ -211,7 +213,7 @@ static void f_modown(struct file *filp, struct pid *pid, enum pid_type type,
                        filp->f_owner.euid = cred->euid;
                }
        }
-       write_unlock_irq(&filp->f_owner.lock);
+       write_unlock_irqrestore(&filp->f_owner.lock, flags);
 }
 
 int __f_setown(struct file *filp, struct pid *pid, enum pid_type type,