linux-kernel - [46/89] fnctl: f_modown should call write_lock

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Message-Id: <20100330225836.830303692@linux.site>
Date:	Tue, 30 Mar 2010 15:57:48 -0700
From:	Greg KH <gregkh@...e.de>
To:	linux-kernel@...r.kernel.org, stable@...nel.org
Cc:	stable-review@...nel.org, torvalds@...ux-foundation.org,
	akpm@...ux-foundation.org, alan@...rguk.ukuu.org.uk,
	"Eric W. Biederman" <ebiederm@...ssion.com>,
	Al Viro <viro@...IV.linux.org.uk>,
	Tavis Ormandy <taviso@...gle.com>,
	Greg Kroah-Hartman <gregkh@...e.de>
Subject: [46/89] fnctl: f_modown should call write_lock_irqsave/restore

2.6.31-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Greg Kroah-Hartman <gregkh@...e.de>

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@...ssion.com>
Cc: Al Viro <viro@...IV.linux.org.uk>
Cc: Alan Cox <alan@...rguk.ukuu.org.uk>
Cc: Tavis Ormandy <taviso@...gle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...e.de>
Signed-off-by: Linus Torvalds <torvalds@...ux-foundation.org>

---
 fs/fcntl.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

--- a/fs/fcntl.c
+++ b/fs/fcntl.c
@@ -199,7 +199,9 @@ static int setfl(int fd, struct file * f
 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,
 			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,


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