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. Also ctx's kobject is embedded into each ctx pointed by hctx->ctxs[], which shouldn't have been released so early. [1], 6cd18e711dd8075 (block: destroy bdi before blockdev is unregistered) Reported-by: Stefan Seyfried <[email protected]> Cc: NeilBrown <[email protected]> Cc: Christoph Hellwig <[email protected]> Cc: [email protected] (v4.0) Signed-off-by: Ming Lei <[email protected]> --- block/blk-mq.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/block/blk-mq.c b/block/blk-mq.c index e68b71b..594eea0 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -1600,6 +1600,7 @@ 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) @@ -1618,7 +1619,6 @@ 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); } @@ -1891,8 +1891,12 @@ 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); -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
