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| author | Konstantin Khlebnikov <khlebnikov@yandex-team.ru> | 2015-02-09 16:42:49 +0300 |
|---|---|---|
| committer | Jens Axboe <axboe@fb.com> | 2015-02-09 20:22:39 +0300 |
| commit | 69abaffec7d47a083739b79e3066cb3730eba72e (patch) | |
| tree | e217ce01355ab8b2ca1d58c54c983fda70e026f2 | |
| parent | 9f9ee1f2b2f94f19437ae2def7c0d6636d7fe02e (diff) | |
| download | linux-69abaffec7d47a083739b79e3066cb3730eba72e.tar.xz | |
cfq-iosched: handle failure of cfq group allocation
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")
Cc: stable@kernel.org
Signed-off-by: Jens Axboe <axboe@fb.com>
| -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 b9abdca84c17..5da8e6e9ab4b 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -3590,6 +3590,11 @@ 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); /* @@ -3626,7 +3631,7 @@ retry: } else cfqq = &cfqd->oom_cfqq; } - +out: if (new_cfqq) kmem_cache_free(cfq_pool, new_cfqq); |