Hi,
在 2023/05/10 9:49, Yu Kuai 写道:
Hi,
在 2023/05/10 9:29, Yu Kuai 写道:
Hi,
在 2023/05/10 8:49, Guangwu Zhang 写道:
Hi,
We found this kernel NULL pointer issue with latest
linux-block/for-next, please check it.
Kernel repo:
https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git
[ 112.483804] BUG: kernel NULL pointer dereference, address:
0000000000000048
Base on this offset, 0x48 match bio->bi_blkg, so I guess this is because
bio is NULL, so the problem is that passthrough request insert into
elevator.
Sorry that attached patch has some problem, please try this one.
diff --git a/block/blk-mq.c b/block/blk-mq.c
index f6dad0886a2f..bd94d8a5416f 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2712,6 +2712,7 @@ static void blk_mq_dispatch_plug_list(struct
blk_plug *plug, bool from_sched)
struct request **requeue_lastp = &requeue_list;
unsigned int depth = 0;
LIST_HEAD(list);
+ LIST_HEAD(passthrough_list);
do {
struct request *rq = rq_list_pop(&plug->mq_list);
@@ -2723,7 +2724,10 @@ static void blk_mq_dispatch_plug_list(struct
blk_plug *plug, bool from_sched)
rq_list_add_tail(&requeue_lastp, rq);
continue;
}
- list_add(&rq->queuelist, &list);
+ if (blk_rq_is_passthrough(rq))
+ list_add(&rq->queuelist, &passthrough_list);
+ else
+ list_add(&rq->queuelist, &list);
depth++;
} while (!rq_list_empty(plug->mq_list));
@@ -2731,6 +2735,9 @@ static void blk_mq_dispatch_plug_list(struct
blk_plug *plug, bool from_sched)
trace_block_unplug(this_hctx->queue, depth, !from_sched);
percpu_ref_get(&this_hctx->queue->q_usage_counter);
+ if (!list_empty(&passthrough_list))
+ blk_mq_insert_requests(this_hctx, this_ctx,
&passthrough_list,
+ from_sched);
if (this_hctx->queue->elevator) {
this_hctx->queue->elevator->type->ops.insert_requests(this_hctx,
&list, 0);
Thanks,
Kuai
