diff options
| author | Paolo Valente <paolo.valente@linaro.org> | 2020-02-03 13:40:56 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-03-12 15:00:08 +0300 |
| commit | 594fca1d04fbc5b0720f758b397ad8d94699163b (patch) | |
| tree | bd16259f9ad5272ac7da3483dd9d0bfc688e7306 /block | |
| parent | cff670b3eb68257029e2977a6bfeac7d9b829e9a (diff) | |
| download | linux-594fca1d04fbc5b0720f758b397ad8d94699163b.tar.xz | |
block, bfq: get extra ref to prevent a queue from being freed during a group move
[ Upstream commit ecedd3d7e19911ab8fe42f17b77c0a30fe7f4db3 ]
In bfq_bfqq_move(), the bfq_queue, say Q, to be moved to a new group
may happen to be deactivated in the scheduling data structures of the
source group (and then activated in the destination group). If Q is
referred only by the data structures in the source group when the
deactivation happens, then Q is freed upon the deactivation.
This commit addresses this issue by getting an extra reference before
the possible deactivation, and releasing this extra reference after Q
has been moved.
Tested-by: Chris Evich <cevich@redhat.com>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Signed-off-by: Paolo Valente <paolo.valente@linaro.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'block')
| -rw-r--r-- | block/bfq-cgroup.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/block/bfq-cgroup.c b/block/bfq-cgroup.c index 86a607cf19a1..ca5ffe26178e 100644 --- a/block/bfq-cgroup.c +++ b/block/bfq-cgroup.c @@ -634,6 +634,12 @@ void bfq_bfqq_move(struct bfq_data *bfqd, struct bfq_queue *bfqq, bfq_bfqq_expire(bfqd, bfqd->in_service_queue, false, BFQQE_PREEMPTED); + /* + * get extra reference to prevent bfqq from being freed in + * next possible deactivate + */ + bfqq->ref++; + if (bfq_bfqq_busy(bfqq)) bfq_deactivate_bfqq(bfqd, bfqq, false, false); else if (entity->on_st) @@ -653,6 +659,8 @@ void bfq_bfqq_move(struct bfq_data *bfqd, struct bfq_queue *bfqq, if (!bfqd->in_service_queue && !bfqd->rq_in_driver) bfq_schedule_dispatch(bfqd); + /* release extra ref taken above */ + bfq_put_queue(bfqq); } /** |