Message ID | 1264758203-7591-1-git-send-email-stefan.bader@canonical.com |
---|---|
State | Accepted |
Delegated to: | Stefan Bader |
Headers | show |
On Fri, Jan 29, 2010 at 10:43:23AM +0100, Stefan Bader wrote: > SRU Justification: > > Impact: While we have no real bug reported (at least not one we can simply > connect to it) I really would like to have this backported to Karmic. > > Fix: This has gone into 2.6.32.y (and 2.6.27.y) and moving from a *_irq to > a *_irqsave variant can only make things better. Plus we might get patches > that expose the problem, too. And then forget to pull this as well. > > Thoughts? I would create a bug report for it, should we decide it should > go in. Seems that there is a known case where we can call it with IRQs disabled, and with the _irq variant all sorts of hard to diagnose hangs would be possible. I'd support putting that in given its a call which can be tickled from userspace. -apw
Stefan Bader wrote: > SRU Justification: > > Impact: While we have no real bug reported (at least not one we can simply > connect to it) I really would like to have this backported to Karmic. > > Fix: This has gone into 2.6.32.y (and 2.6.27.y) and moving from a *_irq to > a *_irqsave variant can only make things better. Plus we might get patches > that expose the problem, too. And then forget to pull this as well. > > Thoughts? I would create a bug report for it, should we decide it should > go in. > > -Stefan > > From 0a1c275a44db55b2624652b04d4ed9430e82957b Mon Sep 17 00:00:00 2001 > From: Greg Kroah-Hartman <gregkh@suse.de> > Date: Tue, 26 Jan 2010 15:04:02 -0800 > Subject: [PATCH] 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> > Signed-off-by: Stefan Bader <stefan.bader@canonical.com> > --- > fs/fcntl.c | 6 ++++-- > 1 files changed, 4 insertions(+), 2 deletions(-) > > diff --git a/fs/fcntl.c b/fs/fcntl.c > index 97e01dc..5ef953e 100644 > --- 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, Acked-by: Tim Gardner <tim.gardner@canonical.com>
Applied and pushed
diff --git a/fs/fcntl.c b/fs/fcntl.c index 97e01dc..5ef953e 100644 --- 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,