| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.0 094/105] blk-mq: free hctx->ctxs in queues release handler | Date | Fri, 19 Jun 2015 13:36:24 -0700 |
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4.0-stable review patch. If anyone has any objections, please let me know.
------------------
From: Ming Lei <tom.leiming@gmail.com>
commit c3b4afca7023b5aa0531912364246e67f79b3010 upstream.
Now blk_cleanup_queue() can be called before calling del_gendisk()[1], inside which hctx->ctxs is touched from blk_mq_unregister_hctx(), but the variable has been freed by blk_cleanup_queue() at that time.
So this patch moves freeing of hctx->ctxs into queue's release handler for fixing the oops reported by Stefan.
[1], 6cd18e711dd8075 (block: destroy bdi before blockdev is unregistered)
Reported-by: Stefan Seyfried <stefan.seyfried@googlemail.com> Cc: NeilBrown <neilb@suse.de> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Ming Lei <tom.leiming@gmail.com> Signed-off-by: Jens Axboe <axboe@fb.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- block/blk-mq.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
--- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -1589,6 +1589,7 @@ static int blk_mq_hctx_notify(void *data return NOTIFY_OK; } +/* hctx->ctxs will be freed in queue's release handler */ static void blk_mq_exit_hctx(struct request_queue *q, struct blk_mq_tag_set *set, struct blk_mq_hw_ctx *hctx, unsigned int hctx_idx) @@ -1607,7 +1608,6 @@ static void blk_mq_exit_hctx(struct requ blk_mq_unregister_cpu_notifier(&hctx->cpu_notifier); blk_free_flush_queue(hctx->fq); - kfree(hctx->ctxs); blk_mq_free_bitmap(&hctx->ctx_map); } @@ -1873,8 +1873,12 @@ void blk_mq_release(struct request_queue unsigned int i; /* hctx kobj stays in hctx */ - queue_for_each_hw_ctx(q, hctx, i) + queue_for_each_hw_ctx(q, hctx, i) { + if (!hctx) + continue; + kfree(hctx->ctxs); kfree(hctx); + } kfree(q->queue_hw_ctx);
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