From aa0c680c3aa96a5f9f160d90dd95402ad578e2b0 Mon Sep 17 00:00:00 2001 From: Rafael Mendonca Date: Thu, 11 Aug 2022 20:23:37 -0300 Subject: [PATCH] block: Do not call blk_put_queue() if gendisk allocation fails Commit 6f8191fdf41d ("block: simplify disk shutdown") removed the call to blk_get_queue() during gendisk allocation but missed to remove the corresponding cleanup code blk_put_queue() for it. Thus, if the gendisk allocation fails, the request_queue refcount gets decremented and reaches 0, causing blk_mq_release() to be called with a hctx still alive. That triggers a WARNING report, as found by syzkaller: ------------[ cut here ]------------ WARNING: CPU: 0 PID: 23016 at block/blk-mq.c:3881 blk_mq_release+0xf8/0x3e0 block/blk-mq.c:3881 [...] stripped RIP: 0010:blk_mq_release+0xf8/0x3e0 block/blk-mq.c:3881 [...] stripped Call Trace: blk_release_queue+0x153/0x270 block/blk-sysfs.c:780 kobject_cleanup lib/kobject.c:673 [inline] kobject_release lib/kobject.c:704 [inline] kref_put include/linux/kref.h:65 [inline] kobject_put+0x1c8/0x540 lib/kobject.c:721 __alloc_disk_node+0x4f7/0x610 block/genhd.c:1388 __blk_mq_alloc_disk+0x13b/0x1f0 block/blk-mq.c:3961 loop_add+0x3e2/0xaf0 drivers/block/loop.c:1978 loop_control_ioctl+0x133/0x620 drivers/block/loop.c:2150 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl fs/ioctl.c:856 [inline] __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:856 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd [...] stripped Fixes: 6f8191fdf41d ("block: simplify disk shutdown") Reported-by: syzbot+31c9594f6e43b9289b25@syzkaller.appspotmail.com Suggested-by: Hillf Danton Signed-off-by: Rafael Mendonca Reviewed-by: Christoph Hellwig Link: https://lore.kernel.org/r/20220811232338.254673-1-rafaelmendsr@gmail.com Signed-off-by: Jens Axboe --- block/genhd.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/block/genhd.c b/block/genhd.c index b901fea1d55a..d36fabf0abc1 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -1341,7 +1341,7 @@ struct gendisk *__alloc_disk_node(struct request_queue *q, int node_id, disk = kzalloc_node(sizeof(struct gendisk), GFP_KERNEL, node_id); if (!disk) - goto out_put_queue; + return NULL; if (bioset_init(&disk->bio_split, BIO_POOL_SIZE, 0, 0)) goto out_free_disk; @@ -1390,8 +1390,6 @@ struct gendisk *__alloc_disk_node(struct request_queue *q, int node_id, bioset_exit(&disk->bio_split); out_free_disk: kfree(disk); -out_put_queue: - blk_put_queue(q); return NULL; }