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blk-mq: free hctx->ctxs in queue's release handler

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commit c3b4afca70 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], 6cd18e711d (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>
This commit is contained in:
Ming Lei 2015-06-04 22:25:04 +08:00 committed by Greg Kroah-Hartman
parent 0ffafd0b1b
commit 3804579f5c
1 changed files with 6 additions and 2 deletions
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8
block/blk-mq.c
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@ -1589,6 +1589,7 @@ static int blk_mq_hctx_notify(void *data, unsigned long action,
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 request_queue *q,
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 *q)
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);