Am Samstag, den 28.07.2007, 23:55 -0700 schrieb Andrew Morton:
> On Fri, 27 Jul 2007 16:46:23 +0200 Maik Hampel <[EMAIL PROTECTED]> wrote:
> 
> > In case of read errors raid10d tries to print a nice error message,
> > unfortunately using data from an already put bio.
> > 
> > Signed-off-by: Maik Hampel <[EMAIL PROTECTED]>
> > 
> > diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
> > index f730a14..ea1b3e3 100644
> > --- a/drivers/md/raid10.c
> > +++ b/drivers/md/raid10.c
> > @@ -1557,7 +1557,6 @@ static void raid10d(mddev_t *mddev)
> >                     bio = r10_bio->devs[r10_bio->read_slot].bio;
> >                     r10_bio->devs[r10_bio->read_slot].bio =
> >                             mddev->ro ? IO_BLOCKED : NULL;
> > -                   bio_put(bio);
> >                     mirror = read_balance(conf, r10_bio);
> >                     if (mirror == -1) {
> >                             printk(KERN_ALERT "raid10: %s: unrecoverable 
> > I/O"
> > @@ -1567,6 +1566,7 @@ static void raid10d(mddev_t *mddev)
> >                             raid_end_bio_io(r10_bio);
> >                     } else {
> >                             const int do_sync = 
> > bio_sync(r10_bio->master_bio);
> > +                           bio_put(bio);
> >                             rdev = conf->mirrors[mirror].rdev;
> >                             if (printk_ratelimit())
> >                                     printk(KERN_ERR "raid10: %s: 
> > redirecting sector %llu to"
> > 
> > 
> 
> Surely we just leaked that bio if (mirror == -1)?
> 
> better:
> 
> --- a/drivers/md/raid10.c~md-raid10-fix-use-after-free-of-bio
> +++ a/drivers/md/raid10.c
> @@ -1534,7 +1534,6 @@ static void raid10d(mddev_t *mddev)
>                       bio = r10_bio->devs[r10_bio->read_slot].bio;
>                       r10_bio->devs[r10_bio->read_slot].bio =
>                               mddev->ro ? IO_BLOCKED : NULL;
> -                     bio_put(bio);
>                       mirror = read_balance(conf, r10_bio);
>                       if (mirror == -1) {
>                               printk(KERN_ALERT "raid10: %s: unrecoverable 
> I/O"
> @@ -1542,8 +1541,10 @@ static void raid10d(mddev_t *mddev)
>                                      bdevname(bio->bi_bdev,b),
>                                      (unsigned long long)r10_bio->sector);
>                               raid_end_bio_io(r10_bio);
> +                             bio_put(bio);
raid_end_bio_io() calls put_all_bios(), which does a bio_put() to
corresponding r10_bio->devs[i]. So this looks like redundant code for
me.
>                       } else {
>                               const int do_sync = 
> bio_sync(r10_bio->master_bio);
> +                             bio_put(bio);
>                               rdev = conf->mirrors[mirror].rdev;
>                               if (printk_ratelimit())
>                                       printk(KERN_ERR "raid10: %s: 
> redirecting sector %llu to"

Regards, 
Maik Hampel


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