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mirror: Fix access of uninitialised fields during start 

bdrv_mirror_top_pwritev() accesses the job object when active mirroring
is enabled. It disables this code during early initialisation while
s->job isn't set yet.

However, s->job is still set way too early when the job object isn't
fully initialised. For example, &s->ops_in_flight isn't initialised yet
and the in_flight bitmap doesn't exist yet. This causes crashes when a
write request comes in too early.

Move the assignment of s->job to when the mirror job is actually fully
initialised to make sure that the mirror_top driver doesn't access it
too early.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20230203152202.49054-3-kwolf@redhat.com>
Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Kevin Wolf 2023-02-03 16:21:41 +01:00
parent 10e5d70787
commit 32125b1460
1 changed files with 7 additions and 1 deletions
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8
block/mirror.c
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@ -896,6 +896,7 @@ static int coroutine_fn mirror_run(Job *job, Error **errp)
{
MirrorBlockJob *s = container_of(job, MirrorBlockJob, common.job);
BlockDriverState *bs = s->mirror_top_bs->backing->bs;
MirrorBDSOpaque *mirror_top_opaque = s->mirror_top_bs->opaque;
BlockDriverState *target_bs = blk_bs(s->target);
bool need_drain = true;
BlockDeviceIoStatus iostatus;
@ -985,6 +986,12 @@ static int coroutine_fn mirror_run(Job *job, Error **errp)
}
}
/*
* Only now the job is fully initialised and mirror_top_bs should start
* accessing it.
*/
mirror_top_opaque->job = s;
assert(!s->dbi);
s->dbi = bdrv_dirty_iter_new(s->dirty_bitmap);
for (;;) {
@ -1704,7 +1711,6 @@ static BlockJob *mirror_start_job(
if (!s) {
goto fail;
}
bs_opaque->job = s;
/* The block job now has a reference to this node */
bdrv_unref(mirror_top_bs);