Messages in this thread | | | From | KOSAKI Motohiro <> | Subject | Re: [Patch] fix the lockdep warning in tty_fasync() | Date | Wed, 27 Jan 2010 10:09:04 +0900 (JST) |
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> Commit 703625118 causes a lockdep warning: > > [ INFO: possible irq lock inversion dependency detected ] > 2.6.33-rc5 #77 > --------------------------------------------------------- > emacs/1609 just changed the state of lock: > (&(&tty->ctrl_lock)->rlock){+.....}, at: [<ffffffff8127c648>] > tty_fasync+0xe8/0x190 > but this lock took another, HARDIRQ-unsafe lock in the past: > (&(&sighand->siglock)->rlock){-.....} > > This is due to we use write_lock_irq() in __f_setown() which turns > the IRQ on in write_unlock_irq(), causes this warning. > > Switch it to write_lock_irqsave() and write_unlock_irqrestore(), > as suggested by Eric. > > Reported-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> > Signed-off-by: WANG Cong <xiyou.wangcong@gmail.com> > Cc: "Eric W. Biederman" <ebiederm@xmission.com> > > --- > diff --git a/fs/fcntl.c b/fs/fcntl.c > index 97e01dc..82cc8a7 100644 > --- a/fs/fcntl.c > +++ b/fs/fcntl.c > @@ -199,7 +199,8 @@ 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 +212,7 @@ 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,
I've confirmed the warning disappear :)
Thanks.
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