From: Eric Blake <eblake@redhat.com>
To: Stefan Hajnoczi <stefanha@redhat.com>, qemu-devel@nongnu.org
Cc: Kevin Wolf <kwolf@redhat.com>, John Snow <jsnow@redhat.com>
Subject: Re: [Qemu-devel] [PATCH v2 2/4] block: add BlockBackend->in_flight counter
Date: Tue, 13 Feb 2018 10:03:55 -0600 [thread overview]
Message-ID: <49797c75-1e96-10fe-4be5-58cd2b0ebd7f@redhat.com> (raw)
In-Reply-To: <20180213142102.14450-3-stefanha@redhat.com>
On 02/13/2018 08:21 AM, Stefan Hajnoczi wrote:
> BlockBackend currently relies on BlockDriverState->in_flight to track
> requests for blk_drain(). There is a corner case where
> BlockDriverState->in_flight cannot be used though: blk->root can be NULL
> when there is no medium. This results in a segfault when the NULL
> pointer is dereferenced.
>
> Introduce a BlockBackend->in_flight counter for aio requests so it works
> even when blk->root == NULL.
>
> Based on a patch by Kevin Wolf <kwolf@redhat.com>.
>
> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> ---
> block.c | 2 +-
> block/block-backend.c | 60 +++++++++++++++++++++++++++++++++++++++++++++------
> 2 files changed, 54 insertions(+), 8 deletions(-)
>
Reviewed-by: Eric Blake <eblake@redhat.com>
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3266
Virtualization: qemu.org | libvirt.org
next prev parent reply other threads:[~2018-02-13 16:04 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-13 14:20 [Qemu-devel] [PATCH v2 0/4] block: fix blk_aio_*() segfault when blk->root == NULL Stefan Hajnoczi
2018-02-13 14:20 ` [Qemu-devel] [PATCH v2 1/4] block: extract AIO_WAIT_WHILE() from BlockDriverState Stefan Hajnoczi
2018-02-13 16:01 ` Eric Blake
2018-02-14 14:06 ` Stefan Hajnoczi
2018-02-14 22:31 ` Eric Blake
2018-02-15 9:27 ` Stefan Hajnoczi
2018-02-15 10:12 ` Kevin Wolf
2018-02-15 14:15 ` Eric Blake
2018-02-14 22:33 ` Eric Blake
2018-02-13 14:21 ` [Qemu-devel] [PATCH v2 2/4] block: add BlockBackend->in_flight counter Stefan Hajnoczi
2018-02-13 16:03 ` Eric Blake [this message]
2018-02-13 14:21 ` [Qemu-devel] [PATCH v2 3/4] block: test blk_aio_flush() with blk->root == NULL Stefan Hajnoczi
2018-02-13 14:21 ` [Qemu-devel] [PATCH v2 4/4] Revert "IDE: Do not flush empty CDROM drives" Stefan Hajnoczi
2018-02-15 9:28 ` [Qemu-devel] [PATCH v2 0/4] block: fix blk_aio_*() segfault when blk->root == NULL Stefan Hajnoczi
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