From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Morton Subject: Re: md: raid10: fix use-after-free of bio Date: Sat, 28 Jul 2007 23:55:19 -0700 Message-ID: <20070728235519.1edc6ccb.akpm@linux-foundation.org> References: <1185547583.2663.10.camel@c64> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1185547583.2663.10.camel@c64> Sender: linux-raid-owner@vger.kernel.org To: Maik Hampel Cc: Neil Brown , "linux-kernel@vger.kernel.org" , "linux-raid@vger.kernel.org" List-Id: linux-raid.ids On Fri, 27 Jul 2007 16:46:23 +0200 Maik Hampel 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 > > 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); } 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" _