diff options
| author | Konstantin Khlebnikov <khlebnikov@yandex-team.ru> | 2015-02-09 16:42:49 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-03-06 14:43:29 -0800 |
| commit | 16f3a871c431a52d1461e88cf3c0d2e828366930 (patch) | |
| tree | 4400701772fdfe05e0ef357fcf4b03c14351d82d | |
| parent | eec188a371a6ad6f8f7188980d08918f0e4256ee (diff) | |
cfq-iosched: handle failure of cfq group allocation
commit 69abaffec7d47a083739b79e3066cb3730eba72e upstream.
Cfq_lookup_create_cfqg() allocates struct blkcg_gq using GFP_ATOMIC.
In cfq_find_alloc_queue() possible allocation failure is not handled.
As a result kernel oopses on NULL pointer dereference when
cfq_link_cfqq_cfqg() calls cfqg_get() for NULL pointer.
Bug was introduced in v3.5 in commit cd1604fab4f9 ("blkcg: factor
out blkio_group creation"). Prior to that commit cfq group lookup
had returned pointer to root group as fallback.
This patch handles this error using existing fallback oom_cfqq.
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Fixes: cd1604fab4f9 ("blkcg: factor out blkio_group creation")
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | block/cfq-iosched.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index 91c25f261c91..de66a476e356 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -3585,6 +3585,11 @@ retry: blkcg = bio_blkcg(bio); cfqg = cfq_lookup_create_cfqg(cfqd, blkcg); + if (!cfqg) { + cfqq = &cfqd->oom_cfqq; + goto out; + } + cfqq = cic_to_cfqq(cic, is_sync); /* @@ -3621,7 +3626,7 @@ retry: } else cfqq = &cfqd->oom_cfqq; } - +out: if (new_cfqq) kmem_cache_free(cfq_pool, new_cfqq); |