* [PATCH] block: make sure that bvec length can't be overflowed
@ 2019-04-16 15:38 Ming Lei
2019-04-16 16:46 ` Christoph Hellwig
2019-04-17 11:52 ` Hannes Reinecke
0 siblings, 2 replies; 5+ messages in thread
From: Ming Lei @ 2019-04-16 15:38 UTC (permalink / raw)
To: Jens Axboe; +Cc: linux-block, Ming Lei, Christoph Hellwig, Yi Zhang
bvec->bv_offset may be bigger than PAGE_SIZE sometimes, such as,
when one bio is splitted in the middle of one bvec via bio_split(),
and bi_iter.bi_bvec_done is used to build offset of the 1st bvec of
remained bio.
So we have to make sure that every bvec's offset is less than
PAGE_SIZE from bio_for_each_segment().
This patch fixes this issue reported by Zhang Yi When running nvme/011.
Cc: Christoph Hellwig <hch@lst.de>
Cc: Yi Zhang <yi.zhang@redhat.com>
Reported-by: Yi Zhang <yi.zhang@redhat.com>
Fixes: 6dc4f100c175 ("block: allow bio_for_each_segment_all() to iterate over multi-page bvec")
Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
include/linux/bvec.h | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/include/linux/bvec.h b/include/linux/bvec.h
index 3bc91879e1e2..f179b370066f 100644
--- a/include/linux/bvec.h
+++ b/include/linux/bvec.h
@@ -160,8 +160,9 @@ static inline void bvec_advance(const struct bio_vec *bvec,
bv->bv_page = nth_page(bv->bv_page, 1);
bv->bv_offset = 0;
} else {
- bv->bv_page = bvec->bv_page;
- bv->bv_offset = bvec->bv_offset;
+ bv->bv_page = bvec_nth_page(bvec->bv_page, bvec->bv_offset /
+ PAGE_SIZE);
+ bv->bv_offset = bvec->bv_offset % PAGE_SIZE;
}
bv->bv_len = min_t(unsigned int, PAGE_SIZE - bv->bv_offset,
bvec->bv_len - iter_all->done);
--
2.9.5
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH] block: make sure that bvec length can't be overflowed
2019-04-16 15:38 [PATCH] block: make sure that bvec length can't be overflowed Ming Lei
@ 2019-04-16 16:46 ` Christoph Hellwig
2019-04-16 17:03 ` Jens Axboe
2019-04-17 11:52 ` Hannes Reinecke
1 sibling, 1 reply; 5+ messages in thread
From: Christoph Hellwig @ 2019-04-16 16:46 UTC (permalink / raw)
To: Ming Lei; +Cc: Jens Axboe, linux-block, Christoph Hellwig, Yi Zhang
s/overflowed/overflow/ in the subject.
Otherwise this looks good to me:
Reviewed-by: Christoph Hellwig <hch@lst.de>
Although this will create yet another conflict between Linus' tree
and the 5.2 block tree.
Although maybe Jens still reset the tree and move the merge past this..
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] block: make sure that bvec length can't be overflowed
2019-04-16 16:46 ` Christoph Hellwig
@ 2019-04-16 17:03 ` Jens Axboe
2019-04-17 0:48 ` Ming Lei
0 siblings, 1 reply; 5+ messages in thread
From: Jens Axboe @ 2019-04-16 17:03 UTC (permalink / raw)
To: Christoph Hellwig, Ming Lei; +Cc: linux-block, Yi Zhang
On 4/16/19 10:46 AM, Christoph Hellwig wrote:
> s/overflowed/overflow/ in the subject.
>
> Otherwise this looks good to me:
>
> Reviewed-by: Christoph Hellwig <hch@lst.de>
>
> Although this will create yet another conflict between Linus' tree
> and the 5.2 block tree.
>
> Although maybe Jens still reset the tree and move the merge past this..
That was my main worry too... But I'll probably just deal with it and
redo the merge, I don't want to do two, and I don't want to have to
deal with answering for why we get repeated conflicts in this area.
For the patch, I do generally prefer doing an AND with PAGE_MASK
rather than a modulo with PAGE_SIZE. I know the compiler will take
care of it, but still, it's more prudent imho.
--
Jens Axboe
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] block: make sure that bvec length can't be overflowed
2019-04-16 17:03 ` Jens Axboe
@ 2019-04-17 0:48 ` Ming Lei
0 siblings, 0 replies; 5+ messages in thread
From: Ming Lei @ 2019-04-17 0:48 UTC (permalink / raw)
To: Jens Axboe; +Cc: Christoph Hellwig, linux-block, Yi Zhang
On Tue, Apr 16, 2019 at 11:03:00AM -0600, Jens Axboe wrote:
> On 4/16/19 10:46 AM, Christoph Hellwig wrote:
> > s/overflowed/overflow/ in the subject.
> >
> > Otherwise this looks good to me:
> >
> > Reviewed-by: Christoph Hellwig <hch@lst.de>
> >
> > Although this will create yet another conflict between Linus' tree
> > and the 5.2 block tree.
> >
> > Although maybe Jens still reset the tree and move the merge past this..
>
> That was my main worry too... But I'll probably just deal with it and
> redo the merge, I don't want to do two, and I don't want to have to
> deal with answering for why we get repeated conflicts in this area.
This one is a fix which should affect on loop and nvme-loop only in theory.
That is typical conflict between fix and feature(improvement).
Anyway, sorry for the a bit late fix.
>
> For the patch, I do generally prefer doing an AND with PAGE_MASK
> rather than a modulo with PAGE_SIZE. I know the compiler will take
> care of it, but still, it's more prudent imho.
OK, do it in V2.
Thanks,
Ming
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] block: make sure that bvec length can't be overflowed
2019-04-16 15:38 [PATCH] block: make sure that bvec length can't be overflowed Ming Lei
2019-04-16 16:46 ` Christoph Hellwig
@ 2019-04-17 11:52 ` Hannes Reinecke
1 sibling, 0 replies; 5+ messages in thread
From: Hannes Reinecke @ 2019-04-17 11:52 UTC (permalink / raw)
To: Ming Lei, Jens Axboe; +Cc: linux-block, Christoph Hellwig, Yi Zhang
On 4/16/19 5:38 PM, Ming Lei wrote:
> bvec->bv_offset may be bigger than PAGE_SIZE sometimes, such as,
> when one bio is splitted in the middle of one bvec via bio_split(),
> and bi_iter.bi_bvec_done is used to build offset of the 1st bvec of
> remained bio.
>
> So we have to make sure that every bvec's offset is less than
> PAGE_SIZE from bio_for_each_segment().
>
> This patch fixes this issue reported by Zhang Yi When running nvme/011.
>
> Cc: Christoph Hellwig <hch@lst.de>
> Cc: Yi Zhang <yi.zhang@redhat.com>
> Reported-by: Yi Zhang <yi.zhang@redhat.com>
> Fixes: 6dc4f100c175 ("block: allow bio_for_each_segment_all() to iterate over multi-page bvec")
> Signed-off-by: Ming Lei <ming.lei@redhat.com>
> ---
> include/linux/bvec.h | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/include/linux/bvec.h b/include/linux/bvec.h
> index 3bc91879e1e2..f179b370066f 100644
> --- a/include/linux/bvec.h
> +++ b/include/linux/bvec.h
> @@ -160,8 +160,9 @@ static inline void bvec_advance(const struct bio_vec *bvec,
> bv->bv_page = nth_page(bv->bv_page, 1);
> bv->bv_offset = 0;
> } else {
> - bv->bv_page = bvec->bv_page;
> - bv->bv_offset = bvec->bv_offset;
> + bv->bv_page = bvec_nth_page(bvec->bv_page, bvec->bv_offset /
> + PAGE_SIZE);
> + bv->bv_offset = bvec->bv_offset % PAGE_SIZE;
> }
> bv->bv_len = min_t(unsigned int, PAGE_SIZE - bv->bv_offset,
> bvec->bv_len - iter_all->done);
>
Looks okay.
Reviewed-by: Hannes Reinecke <hare@suse.com>
Cheers,
Hannes
--
Dr. Hannes Reinecke Teamlead Storage & Networking
hare@suse.de +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: Felix Imendörffer, Mary Higgins, Sri Rasiah
HRB 21284 (AG Nürnberg)
^ permalink raw reply [flat|nested] 5+ messages in thread
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2019-04-16 15:38 [PATCH] block: make sure that bvec length can't be overflowed Ming Lei
2019-04-16 16:46 ` Christoph Hellwig
2019-04-16 17:03 ` Jens Axboe
2019-04-17 0:48 ` Ming Lei
2019-04-17 11:52 ` Hannes Reinecke
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