Messages in this thread Patch in this message | | | Date | Fri, 22 Jan 2010 16:09:49 -0800 | From | Greg KH <> | Subject | [05/29] tty: fix race in tty_fasync |
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2.6.32-stable review patch. If anyone has any objections, please let us know.
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From: Greg Kroah-Hartman <gregkh@suse.de>
commit 703625118069f9f8960d356676662d3db5a9d116 upstream.
We need to keep the lock held over the call to __f_setown() to prevent a PID race.
Thanks to Al Viro for pointing out the problem, and to Travis for making us look here in the first place.
Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Tavis Ormandy <taviso@google.com> Cc: Jeff Dike <jdike@addtoit.com> Cc: Julien Tinnes <jln@google.com> Cc: Matt Mackall <mpm@selenic.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- drivers/char/tty_io.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/char/tty_io.c +++ b/drivers/char/tty_io.c @@ -1930,8 +1930,8 @@ static int tty_fasync(int fd, struct fil pid = task_pid(current); type = PIDTYPE_PID; } - spin_unlock_irqrestore(&tty->ctrl_lock, flags); retval = __f_setown(filp, pid, type, 0); + spin_unlock_irqrestore(&tty->ctrl_lock, flags); if (retval) goto out; } else {
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