==================================================================
BUG: KASAN: use-after-free in rcu_seq_snap kernel/rcu/rcu.h:91 [inline]
BUG: KASAN: use-after-free in srcu_invoke_callbacks+0x391/0x3c0 kernel/rcu/srcutree.c:1283
Read of size 8 at addr ffff888078dd2bc8 by task kworker/1:5/20763

CPU: 1 PID: 20763 Comm: kworker/1:5 Not tainted 5.16.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: rcu_gp srcu_invoke_callbacks
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
 print_address_description.constprop.0.cold+0x8d/0x336 mm/kasan/report.c:255
 __kasan_report mm/kasan/report.c:442 [inline]
 kasan_report.cold+0x83/0xdf mm/kasan/report.c:459
 rcu_seq_snap kernel/rcu/rcu.h:91 [inline]
 srcu_invoke_callbacks+0x391/0x3c0 kernel/rcu/srcutree.c:1283
 process_one_work+0x9ac/0x1650 kernel/workqueue.c:2307
 worker_thread+0x657/0x1110 kernel/workqueue.c:2454
 kthread+0x2e9/0x3a0 kernel/kthread.c:377
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>

Allocated by task 9504:
 kasan_save_stack+0x1e/0x50 mm/kasan/common.c:38
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:437 [inline]
 __kasan_slab_alloc+0x90/0xc0 mm/kasan/common.c:470
 kasan_slab_alloc include/linux/kasan.h:260 [inline]
 slab_post_alloc_hook mm/slab.h:732 [inline]
 slab_alloc_node mm/slub.c:3230 [inline]
 kmem_cache_alloc_node+0x255/0x3f0 mm/slub.c:3266
 blk_alloc_queue+0x5ad/0x870 block/blk-core.c:446
 blk_mq_init_queue_data block/blk-mq.c:3865 [inline]
 __blk_mq_alloc_disk+0x8c/0x1c0 block/blk-mq.c:3889
 nbd_dev_add+0x3b2/0xcd0 drivers/block/nbd.c:1765
 nbd_genl_connect+0x11f3/0x1930 drivers/block/nbd.c:1948
 genl_family_rcv_msg_doit+0x228/0x320 net/netlink/genetlink.c:731
 genl_family_rcv_msg net/netlink/genetlink.c:775 [inline]
 genl_rcv_msg+0x328/0x580 net/netlink/genetlink.c:792
 netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2494
 genl_rcv+0x24/0x40 net/netlink/genetlink.c:803
 netlink_unicast_kernel net/netlink/af_netlink.c:1317 [inline]
 netlink_unicast+0x539/0x7e0 net/netlink/af_netlink.c:1343
 netlink_sendmsg+0x904/0xe00 net/netlink/af_netlink.c:1919
 sock_sendmsg_nosec net/socket.c:705 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:725
 ____sys_sendmsg+0x6e8/0x810 net/socket.c:2413
 ___sys_sendmsg+0xf3/0x170 net/socket.c:2467
 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2496
 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+0x44/0xae

Freed by task 19:
 kasan_save_stack+0x1e/0x50 mm/kasan/common.c:38
 kasan_set_track+0x21/0x30 mm/kasan/common.c:46
 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:370
 ____kasan_slab_free mm/kasan/common.c:367 [inline]
 ____kasan_slab_free+0x130/0x160 mm/kasan/common.c:329
 kasan_slab_free include/linux/kasan.h:236 [inline]
 slab_free_hook mm/slub.c:1728 [inline]
 slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1754
 slab_free mm/slub.c:3509 [inline]
 kmem_cache_free+0xd8/0x340 mm/slub.c:3526
 rcu_do_batch kernel/rcu/tree.c:2527 [inline]
 rcu_core+0x7b8/0x1540 kernel/rcu/tree.c:2778
 __do_softirq+0x29b/0x9c2 kernel/softirq.c:558

Last potentially related work creation:
 kasan_save_stack+0x1e/0x50 mm/kasan/common.c:38
 __kasan_record_aux_stack+0xbe/0xd0 mm/kasan/generic.c:348
 __call_rcu kernel/rcu/tree.c:3026 [inline]
 call_rcu+0xb1/0x740 kernel/rcu/tree.c:3106
 kobject_cleanup lib/kobject.c:705 [inline]
 kobject_release lib/kobject.c:736 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x1c8/0x540 lib/kobject.c:753
 disk_release+0x19a/0x260 block/genhd.c:1116
 device_release+0x9f/0x240 drivers/base/core.c:2229
 kobject_cleanup lib/kobject.c:705 [inline]
 kobject_release lib/kobject.c:736 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x1c8/0x540 lib/kobject.c:753
 put_device+0x1b/0x30 drivers/base/core.c:3512
 put_disk block/genhd.c:1368 [inline]
 blk_cleanup_disk+0x6b/0x80 block/genhd.c:1384
 nbd_dev_remove+0x44/0xf0 drivers/block/nbd.c:253
 process_one_work+0x9ac/0x1650 kernel/workqueue.c:2307
 worker_thread+0x657/0x1110 kernel/workqueue.c:2454
 kthread+0x2e9/0x3a0 kernel/kthread.c:377
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

Second to last potentially related work creation:
 kasan_save_stack+0x1e/0x50 mm/kasan/common.c:38
 __kasan_record_aux_stack+0xbe/0xd0 mm/kasan/generic.c:348
 insert_work+0x48/0x370 kernel/workqueue.c:1368
 __queue_work+0x5ca/0xee0 kernel/workqueue.c:1534
 __queue_delayed_work+0x1c8/0x270 kernel/workqueue.c:1682
 queue_delayed_work_on+0x105/0x120 kernel/workqueue.c:1718
 process_one_work+0x9ac/0x1650 kernel/workqueue.c:2307
 worker_thread+0x657/0x1110 kernel/workqueue.c:2454
 kthread+0x2e9/0x3a0 kernel/kthread.c:377
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

The buggy address belongs to the object at ffff888078dd1ed0
 which belongs to the cache request_queue_srcu of size 3816
The buggy address is located 3320 bytes inside of
 3816-byte region [ffff888078dd1ed0, ffff888078dd2db8)
The buggy address belongs to the page:
page:ffffea0001e37400 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888078dd0000 pfn:0x78dd0
head:ffffea0001e37400 order:3 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 ffffea000069a600 dead000000000005 ffff8881425aab40
raw: ffff888078dd0000 0000000080080006 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 3809, ts 1454130825139, free_ts 1454092171658
 prep_new_page mm/page_alloc.c:2434 [inline]
 get_page_from_freelist+0xa72/0x2f50 mm/page_alloc.c:4165
 __alloc_pages+0x1b2/0x500 mm/page_alloc.c:5389
 alloc_pages+0x1aa/0x310 mm/mempolicy.c:2271
 alloc_slab_page mm/slub.c:1799 [inline]
 allocate_slab mm/slub.c:1944 [inline]
 new_slab+0x28a/0x3b0 mm/slub.c:2004
 ___slab_alloc+0x87c/0xe90 mm/slub.c:3018
 __slab_alloc.constprop.0+0x4d/0xa0 mm/slub.c:3105
 slab_alloc_node mm/slub.c:3196 [inline]
 kmem_cache_alloc_node+0x122/0x3f0 mm/slub.c:3266
 blk_alloc_queue+0x5ad/0x870 block/blk-core.c:446
 blk_mq_init_queue_data block/blk-mq.c:3865 [inline]
 __blk_mq_alloc_disk+0x8c/0x1c0 block/blk-mq.c:3889
 nbd_dev_add+0x3b2/0xcd0 drivers/block/nbd.c:1765
 nbd_genl_connect+0x11f3/0x1930 drivers/block/nbd.c:1948
 genl_family_rcv_msg_doit+0x228/0x320 net/netlink/genetlink.c:731
 genl_family_rcv_msg net/netlink/genetlink.c:775 [inline]
 genl_rcv_msg+0x328/0x580 net/netlink/genetlink.c:792
 netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2494
 genl_rcv+0x24/0x40 net/netlink/genetlink.c:803
 netlink_unicast_kernel net/netlink/af_netlink.c:1317 [inline]
 netlink_unicast+0x539/0x7e0 net/netlink/af_netlink.c:1343
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1352 [inline]
 free_pcp_prepare+0x374/0x870 mm/page_alloc.c:1404
 free_unref_page_prepare mm/page_alloc.c:3325 [inline]
 free_unref_page+0x19/0x690 mm/page_alloc.c:3404
 qlink_free mm/kasan/quarantine.c:157 [inline]
 qlist_free_all+0x6d/0x160 mm/kasan/quarantine.c:176
 kasan_quarantine_reduce+0x180/0x200 mm/kasan/quarantine.c:283
 __kasan_slab_alloc+0xa2/0xc0 mm/kasan/common.c:447
 kasan_slab_alloc include/linux/kasan.h:260 [inline]
 slab_post_alloc_hook mm/slab.h:732 [inline]
 slab_alloc_node mm/slub.c:3230 [inline]
 slab_alloc mm/slub.c:3238 [inline]
 kmem_cache_alloc+0x202/0x3a0 mm/slub.c:3243
 kmem_cache_zalloc include/linux/slab.h:705 [inline]
 ext4_mb_new_blocks+0x93e/0x5320 fs/ext4/mballoc.c:5558
 ext4_ext_map_blocks+0x1f87/0x5f30 fs/ext4/extents.c:4282
 ext4_map_blocks+0x653/0x18a0 fs/ext4/inode.c:638
 ext4_getblk+0x144/0x6b0 fs/ext4/inode.c:849
 ext4_bread+0x2a/0x1c0 fs/ext4/inode.c:902
 ext4_append+0x177/0x3a0 fs/ext4/namei.c:67
 ext4_init_new_dir+0x25e/0x4d0 fs/ext4/namei.c:2893
 ext4_mkdir+0x3cf/0xb20 fs/ext4/namei.c:2939
 vfs_mkdir+0x1c3/0x3b0 fs/namei.c:3883
 do_mkdirat+0x285/0x300 fs/namei.c:3909

Memory state around the buggy address:
 ffff888078dd2a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888078dd2b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888078dd2b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                              ^
 ffff888078dd2c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888078dd2c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================