Hello, syzbot found the following issue on: HEAD commit: 519d81956ee2 Linux 5.15-rc6 git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=1003f734b00000 kernel config: https://syzkaller.appspot.com/x/.config?x=d95853dad8472c91 dashboard link: https://syzkaller.appspot.com/bug?extid=86a4d699d56e1efda543 compiler: Debian clang version 11.0.1-2, GNU ld (GNU Binutils for Debian) 2.35.2 Unfortunately, I don't have any reproducer for this issue yet. IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+86a4d699d56e1efda543@xxxxxxxxxxxxxxxxxxxxxxxxx WARNING: CPU: 0 PID: 484 at lib/debugobjects.c:508 debug_print_object lib/debugobjects.c:505 [inline] WARNING: CPU: 0 PID: 484 at lib/debugobjects.c:508 debug_object_assert_init+0x1fa/0x250 lib/debugobjects.c:895 Modules linked in: CPU: 0 PID: 484 Comm: syz-executor.3 Not tainted 5.15.0-rc6-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:debug_print_object lib/debugobjects.c:505 [inline] RIP: 0010:debug_object_assert_init+0x1fa/0x250 lib/debugobjects.c:895 Code: e8 2b 16 b8 fd 4c 8b 45 00 48 c7 c7 a0 2f b4 8a 48 c7 c6 00 2c b4 8a 48 c7 c2 e0 31 b4 8a 31 c9 49 89 d9 31 c0 e8 b6 c7 36 fd <0f> 0b ff 05 7a 59 c5 09 48 83 c5 38 48 89 e8 48 c1 e8 03 42 80 3c RSP: 0018:ffffc90012ae6e78 EFLAGS: 00010246 RAX: 4660acffeccb0800 RBX: 0000000000000000 RCX: 0000000000040000 RDX: ffffc90010531000 RSI: 000000000000a7fa RDI: 000000000000a7fb RBP: ffffffff8a512d00 R08: ffffffff81693402 R09: ffffed10173857a8 R10: ffffed10173857a8 R11: 0000000000000000 R12: dffffc0000000000 R13: ffff8880b9c00110 R14: 0000000000000003 R15: ffffffff90c0a0a0 FS: 00007f5227fd9700(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000555555c92708 CR3: 000000008b078000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: debug_timer_assert_init kernel/time/timer.c:739 [inline] debug_assert_init kernel/time/timer.c:784 [inline] try_to_del_timer_sync+0xa5/0x3c0 kernel/time/timer.c:1229 del_timer_sync+0x238/0x2f0 kernel/time/timer.c:1382 cleanup_srcu_struct+0x2ca/0x580 kernel/rcu/srcutree.c:379 blk_mq_hw_sysfs_release+0x6c/0x130 block/blk-mq-sysfs.c:40 kobject_cleanup+0x1c0/0x280 lib/kobject.c:705 blk_mq_release+0x255/0x2d0 block/blk-mq.c:3101 blk_release_queue+0x306/0x420 block/blk-sysfs.c:823 kobject_cleanup+0x1c0/0x280 lib/kobject.c:705 __blk_mq_alloc_disk+0x101/0x150 block/blk-mq.c:3149 nbd_dev_add+0x34d/0x940 drivers/block/nbd.c:1721 nbd_genl_connect+0xa66/0x1f50 drivers/block/nbd.c:1889 genl_family_rcv_msg_doit net/netlink/genetlink.c:731 [inline] genl_family_rcv_msg net/netlink/genetlink.c:775 [inline] genl_rcv_msg+0x1032/0x1480 net/netlink/genetlink.c:792 netlink_rcv_skb+0x200/0x470 net/netlink/af_netlink.c:2510 genl_rcv+0x24/0x40 net/netlink/genetlink.c:803 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] netlink_unicast+0x814/0x9f0 net/netlink/af_netlink.c:1345 netlink_sendmsg+0xa29/0xe50 net/netlink/af_netlink.c:1935 sock_sendmsg_nosec net/socket.c:704 [inline] sock_sendmsg net/socket.c:724 [inline] ____sys_sendmsg+0x5b9/0x910 net/socket.c:2409 ___sys_sendmsg net/socket.c:2463 [inline] __sys_sendmsg+0x36f/0x450 net/socket.c:2492 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f522aa84a39 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f5227fd9188 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f522ab88020 RCX: 00007f522aa84a39 RDX: 0000000000000000 RSI: 0000000020000700 RDI: 0000000000000004 RBP: 00007f522aadec5f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffe58c753ff R14: 00007f5227fd9300 R15: 0000000000022000 --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot.