On Thu, Jun 4, 2015 at 9:14 PM, Ming Lei <[email protected]> wrote: > 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.
Hammm, the above line is wrong and should be removed, and hctx->ctxs[] just stores the pointer of ctx. Jens, if you need v1, please let me know. > > [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 > -- Ming Lei -- 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/
