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author | Konstantin Khlebnikov <khlebnikov@yandex-team.ru> | 2015-02-09 16:42:49 +0300 |
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committer | Luis Henriques <luis.henriques@canonical.com> | 2015-03-02 13:17:10 +0000 |
commit | 3b3c7a2a4fc27e14c6fbc2e3d37ff4e62b01d889 (patch) | |
tree | 55cfe9ae074596a3ee64aee76861f2e2f9666ce2 /block | |
parent | 70fd9b703d6a06efaf98908c250c0ec383a49126 (diff) | |
download | linux-stable-3b3c7a2a4fc27e14c6fbc2e3d37ff4e62b01d889.tar.gz linux-stable-3b3c7a2a4fc27e14c6fbc2e3d37ff4e62b01d889.tar.bz2 linux-stable-3b3c7a2a4fc27e14c6fbc2e3d37ff4e62b01d889.zip |
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: Luis Henriques <luis.henriques@canonical.com>
Diffstat (limited to 'block')
-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 f3627ca9303b..2c0585adfaea 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -3582,6 +3582,11 @@ 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); /* @@ -3618,7 +3623,7 @@ retry: } else cfqq = &cfqd->oom_cfqq; } - +out: if (new_cfqq) kmem_cache_free(cfq_pool, new_cfqq); |