From: Chen Jun chenjun102@huawei.com

mainline inclusion from mainline-v6.1-rc4 commit 943f45b9399ed8b2b5190cbc797995edaa97f58f category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/IAXJQY CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...

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There is a kmemleak caused by modprobe null_blk.ko

unreferenced object 0xffff8881acb1f000 (size 1024): comm "modprobe", pid 836, jiffies 4294971190 (age 27.068s) hex dump (first 32 bytes): 00 00 00 00 ad 4e ad de ff ff ff ff 00 00 00 00 .....N.......... ff ff ff ff ff ff ff ff 00 53 99 9e ff ff ff ff .........S...... backtrace: [<000000004a10c249>] kmalloc_node_trace+0x22/0x60 [<00000000648f7950>] blk_mq_alloc_and_init_hctx+0x289/0x350 [<00000000af06de0e>] blk_mq_realloc_hw_ctxs+0x2fe/0x3d0 [<00000000e00c1872>] blk_mq_init_allocated_queue+0x48c/0x1440 [<00000000d16b4e68>] __blk_mq_alloc_disk+0xc8/0x1c0 [<00000000d10c98c3>] 0xffffffffc450d69d [<00000000b9299f48>] 0xffffffffc4538392 [<0000000061c39ed6>] do_one_initcall+0xd0/0x4f0 [<00000000b389383b>] do_init_module+0x1a4/0x680 [<0000000087cf3542>] load_module+0x6249/0x7110 [<00000000beba61b8>] __do_sys_finit_module+0x140/0x200 [<00000000fdcfff51>] do_syscall_64+0x35/0x80 [<000000003c0f1f71>] entry_SYSCALL_64_after_hwframe+0x46/0xb0

That is because q->ma_ops is set to NULL before blk_release_queue is called.

blk_mq_init_queue_data blk_mq_init_allocated_queue blk_mq_realloc_hw_ctxs for (i = 0; i < set->nr_hw_queues; i++) { old_hctx = xa_load(&q->hctx_table, i); if (!blk_mq_alloc_and_init_hctx(.., i, ..)) [1] if (!old_hctx) break;

xa_for_each_start(&q->hctx_table, j, hctx, j) blk_mq_exit_hctx(q, set, hctx, j); [2]

if (!q->nr_hw_queues) [3] goto err_hctxs;

err_exit: q->mq_ops = NULL; [4]

blk_put_queue blk_release_queue if (queue_is_mq(q)) [5] blk_mq_release(q);

[1]: blk_mq_alloc_and_init_hctx failed at i != 0. [2]: The hctxs allocated by [1] are moved to q->unused_hctx_list and will be cleaned up in blk_mq_release. [3]: q->nr_hw_queues is 0. [4]: Set q->mq_ops to NULL. [5]: queue_is_mq returns false due to [4]. And blk_mq_release will not be called. The hctxs in q->unused_hctx_list are leaked.

To fix it, call blk_release_queue in exception path.

Fixes: 2f8f1336a48b ("blk-mq: always free hctx after request queue is freed") Signed-off-by: Yuan Can yuancan@huawei.com Signed-off-by: Chen Jun chenjun102@huawei.com Reviewed-by: Ming Lei ming.lei@redhat.com Link: https://lore.kernel.org/r/20221031031242.94107-1-chenjun102@huawei.com Signed-off-by: Jens Axboe axboe@kernel.dk Conflicts: block/blk-mq.c [commit 4e5cc99e1e48 ("blk-mq: manage hctx map via xarray") is not backported] Signed-off-by: Yu Kuai yukuai3@huawei.com --- block/blk-mq.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/block/blk-mq.c b/block/blk-mq.c index bceb09f27c90..344c55531293 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -3571,9 +3571,7 @@ struct request_queue *blk_mq_init_allocated_queue(struct blk_mq_tag_set *set, return q;

err_hctxs: - kfree(q->queue_hw_ctx); - q->nr_hw_queues = 0; - blk_mq_sysfs_deinit(q); + blk_mq_release(q); err_poll: blk_stat_free_callback(q->poll_cb); q->poll_cb = NULL;