Messages in this thread | | | Date | Fri, 8 Jan 2010 15:18:47 -0800 | From | Andrew Morton <> | Subject | Re: [tip:urgent] fix kfifo_out_locked race bug |
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On Tue, 05 Jan 2010 14:38:35 +0100 Stefani Seibold <stefani@seibold.net> wrote:
> This patch fix a wrong optimization in include/linux/kfifo.h which could > cause a race in kfifo_out_locked. > > Please apply it to the 2.6.33-rc* tree. > > Signed-off-by: Stefani Seibold <stefani@seibold.net> > --- > kfifo.h | 7 ------- > 1 file changed, 7 deletions(-) > > --- linux-2.6.33-rc2.orig/include/linux/kfifo.h 2009-12-27 > 23:37:04.921185257 +0100 > +++ kfifo.h 2010-01-05 14:32:31.414316321 +0100 > @@ -228,13 +228,6 @@ static inline __must_check unsigned int > > ret = kfifo_out(fifo, to, n); > > - /* > - * optimization: if the FIFO is empty, set the indices to 0 > - * so we don't wrap the next time > - */ > - if (kfifo_is_empty(fifo)) > - kfifo_reset(fifo); > - > spin_unlock_irqrestore(lock, flags); > > return ret; >
Thanks. Some nits:
- the patch is wordwrapped. I fixed that up.
- you removed the cc's of the particpants in the earlier dicsussion. I restored them here.
- the changelog didn't describe the bug - what was the race??
- I added "Reported-by: Johan Hovold <jhovold@gmail.com>" to the changelog
- the "[tip:urgent]" tag in the Subject: line is something which Ingo's patch tools add to outgoing email notifications and wasn't appropriate here. Plain old "[patch]" would be typical.
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