Messages in this thread | | | Date | Mon, 5 Sep 2022 08:07:17 +0200 | Subject | Re: [PATCH 1/2] md/raid5: Remove unnecessary bio_put() in raid5_read_one_chunk() | From | Paul Menzel <> |
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Dear Logan, dear David,
Thank you for the patch.
Am 02.09.22 um 19:16 schrieb Logan Gunthorpe: > From: David Sloan <david.sloan@eideticom.com> > > When running chunk-sized reads on disks with badblocks duplicate bio > free/puts are observed: > > ============================================================================= > BUG bio-200 (Not tainted): Object already free > ----------------------------------------------------------------------------- > Allocated in mempool_alloc_slab+0x17/0x20 age=3 cpu=2 pid=7504 > __slab_alloc.constprop.0+0x5a/0xb0
[…]
> The double free is caused by an unnecessary bio_put() in the > if(is_badblock(...)) error path in raid5_read_one_chunk(). > > The error path was moved ahead of bio_alloc_clone() in c82aa1b76787c > ("md/raid5: move checking badblock before clone bio in > raid5_read_one_chunk"). The previous code checked and freed align_bio > which required a bio_put. After he move that is no longer needed as
*t*he move
> raid_bio is returned to the control of the common io path which > performs its own endio resulting in a double free on bad device blocks. > > Fixes: c82aa1b76787c ("md/raid5: move checking badblock before clone bio in raid5_read_one_chunk")
This commit was added to Linux in v5.14-rc1, so it’s not a recent commit – or I misunderstood the cover letter.
Kind regards,
Paul
> Signed-off-by: David Sloan <david.sloan@eideticom.com> > [logang@deltatee.com: minor rewording of commit message] > Signed-off-by: Logan Gunthorpe <logang@deltatee.com> > --- > drivers/md/raid5.c | 1 - > 1 file changed, 1 deletion(-) > > diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c > index 4e6d865a6456..734f92e75f85 100644 > --- a/drivers/md/raid5.c > +++ b/drivers/md/raid5.c > @@ -5538,7 +5538,6 @@ static int raid5_read_one_chunk(struct mddev *mddev, struct bio *raid_bio) > > if (is_badblock(rdev, sector, bio_sectors(raid_bio), &first_bad, > &bad_sectors)) { > - bio_put(raid_bio); > rdev_dec_pending(rdev, mddev); > return 0; > }
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