On Wed, Jun 04, 2014 at 05:06:44PM +0200, Julia Lawall wrote: > > > On Wed, 4 Jun 2014, scameron@xxxxxxxxxxxxxxxxxx wrote: > > > On Wed, Jun 04, 2014 at 11:07:56AM +0200, Julia Lawall wrote: > > > From: Julia Lawall <Julia.Lawall@xxxxxxx> > > > > > > Find_first_zero_bit considers BITS_PER_LONG bits at a time, and thus may > > > return a larger number than the maximum position argument if that position > > > is not a multiple of BITS_PER_LONG. > > > > > > The semantic match that finds this problem is as follows: > > > (http://coccinelle.lip6.fr/) > > > > > > // <smpl> > > > @@ > > > expression e1,e2,e3; > > > statement S1,S2; > > > @@ > > > > > > e1 = find_first_zero_bit(e2,e3) > > > ... > > > if (e1 > > > - == > > > + >= > > > e3) > > > S1 else S2 > > > // </smpl> > > > > > > Signed-off-by: Julia Lawall <Julia.Lawall@xxxxxxx> > > > > > > --- > > > drivers/scsi/hpsa.c | 2 +- > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > diff -u -p a/drivers/scsi/hpsa.c b/drivers/scsi/hpsa.c > > > --- a/drivers/scsi/hpsa.c > > > +++ b/drivers/scsi/hpsa.c > > > @@ -4703,7 +4703,7 @@ static struct CommandList *cmd_alloc(str > > > spin_lock_irqsave(&h->lock, flags); > > > do { > > > i = find_first_zero_bit(h->cmd_pool_bits, h->nr_cmds); > > > - if (i == h->nr_cmds) { > > > + if (i >= h->nr_cmds) { > > > spin_unlock_irqrestore(&h->lock, flags); > > > return NULL; > > > } > > > > Thanks, Ack. > > > > You can add > > > > Reviewed-by: Stephen M. Cameron <scameron@xxxxxxxxxxxxxxxxxx> > > > > to this patch if you want. > > > > You might also consider adding "Cc: stable@xxxxxxxxxxxxxxx" to the sign-off area. > > Actually, it seems that the function can never overshoot the specified > limit. So the change is not needed. Well, that would explain why nobody has complained about it in all these years. I figured that must have been the case at least on x86, but I thought maybe other archictectures might behave differently, and the change seemed harmless in any case. -- steve -- To unsubscribe from this list: send the line "unsubscribe kernel-janitors" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
