From: Christoph Hellwig <hch@lst.de>
To: Matthew Wilcox <willy@infradead.org>
Cc: Jens Axboe <axboe@kernel.dk>, Mike Snitzer <msnitzer@redhat.com>,
"Darrick J. Wong" <djwong@kernel.org>,
linux-block@vger.kernel.org, dm-devel@redhat.com,
Mikulas Patocka <mpatocka@redhat.com>,
Christoph Hellwig <hch@lst.de>
Subject: Re: [dm-devel] [PATCH] block: fix a crash when bio_for_each_folio_all iterates over an empty bio
Date: Tue, 18 Apr 2023 06:57:19 +0200 [thread overview]
Message-ID: <20230418045719.GA29490@lst.de> (raw)
In-Reply-To: <ZD2e5lw5CqueygSA@casper.infradead.org>
On Mon, Apr 17, 2023 at 08:32:54PM +0100, Matthew Wilcox wrote:
> On Mon, Apr 17, 2023 at 03:11:57PM -0400, Mikulas Patocka wrote:
> > If we use bio_for_each_folio_all on an empty bio, it will access the first
> > bio vector unconditionally (it is uninitialized) and it may crash
> > depending on the uninitialized data.
>
> Wait, how do we have an empty bio in the first place?
flush bios are always empty. Not sure iterating over them makes much
sense, though.
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WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@lst.de>
To: Matthew Wilcox <willy@infradead.org>
Cc: Mikulas Patocka <mpatocka@redhat.com>,
Jens Axboe <axboe@kernel.dk>, Christoph Hellwig <hch@lst.de>,
"Darrick J. Wong" <djwong@kernel.org>,
Mike Snitzer <msnitzer@redhat.com>,
dm-devel@redhat.com, linux-block@vger.kernel.org
Subject: Re: [PATCH] block: fix a crash when bio_for_each_folio_all iterates over an empty bio
Date: Tue, 18 Apr 2023 06:57:19 +0200 [thread overview]
Message-ID: <20230418045719.GA29490@lst.de> (raw)
In-Reply-To: <ZD2e5lw5CqueygSA@casper.infradead.org>
On Mon, Apr 17, 2023 at 08:32:54PM +0100, Matthew Wilcox wrote:
> On Mon, Apr 17, 2023 at 03:11:57PM -0400, Mikulas Patocka wrote:
> > If we use bio_for_each_folio_all on an empty bio, it will access the first
> > bio vector unconditionally (it is uninitialized) and it may crash
> > depending on the uninitialized data.
>
> Wait, how do we have an empty bio in the first place?
flush bios are always empty. Not sure iterating over them makes much
sense, though.
next prev parent reply other threads:[~2023-04-18 4:57 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-17 19:11 [dm-devel] [PATCH] block: fix a crash when bio_for_each_folio_all iterates over an empty bio Mikulas Patocka
2023-04-17 19:11 ` Mikulas Patocka
2023-04-17 19:32 ` [dm-devel] " Matthew Wilcox
2023-04-17 19:32 ` Matthew Wilcox
2023-04-17 19:56 ` [dm-devel] " Mikulas Patocka
2023-04-17 19:56 ` Mikulas Patocka
2023-04-18 4:57 ` Christoph Hellwig [this message]
2023-04-18 4:57 ` Christoph Hellwig
2023-04-18 15:20 ` [dm-devel] " Mike Snitzer
2023-04-18 15:20 ` Mike Snitzer
2023-06-09 13:22 ` [dm-devel] " Mike Snitzer
2023-06-09 13:22 ` Mike Snitzer
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