possible deadlock in nbd_disconnect_and

ID	Workflow	Result	Correct	Bug	Created	Started	Finished	Revision	Error
27bb1eda-2be9-4e7e-91d4-d87f75ff8acb	assessment-security	DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌	❓	possible deadlock in nbd_disconnect_and_put	2026/05/30 07:38	2026/05/30 07:38	2026/05/30 08:38	6b4a844333e83556da95d61d7f207e7ef5cd4bc6
8ce3e094-f709-4a73-b084-52a9f4ce04e7	assessment-security		💥	possible deadlock in nbd_disconnect_and_put	2026/05/14 08:37	2026/05/14 08:37	2026/05/14 08:38	6ccb967e465e832a7bfd7a116ad00d52a0923a5d	failed to run ["git" "pull" "origin" "HEAD" "--depth=1" "--allow-unrelated-histories"]: exit status 128 From /app/workdir/repo/linux * branch HEAD -> FETCH_HEAD Updating files: ... truncated to first 200 bytes; open job for full error
8b79b13b-f0b5-4ff1-bf40-8ce7a237bcce	repro		❓	possible deadlock in nbd_disconnect_and_put	2026/03/06 07:38	2026/03/06 07:38	2026/03/06 07:48	31e9c887f7dc24e04b3ca70d0d54fc34141844b0

Title	Replies (including bot)	Last reply
[PATCH] nbd: fix circular lock dependency in nbd_disconnect_and_put	1 (1)	2026/06/30 03:10
[syzbot] [nbd?] possible deadlock in nbd_disconnect_and_put	0 (1)	2026/02/17 19:49

Title

Replies (including bot)

Last reply

[PATCH] nbd: fix circular lock dependency in nbd_disconnect_and_put

1 (1)

2026/06/30 03:10

[syzbot] [nbd?] possible deadlock in nbd_disconnect_and_put

0 (1)

2026/02/17 19:49

block nbd0: NBD_DISCONNECT ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Tainted: G L ------------------------------------------------------ syz.0.3313/21624 is trying to acquire lock: ffff888026fb9940 ((wq_completion)nbd0-recv){+.+.}-{0:0}, at: touch_wq_lockdep_map+0xb5/0x180 kernel/workqueue.c:4037 but task is already holding lock: ffff888026f42260 (&nbd->config_lock){+.+.}-{4:4}, at: nbd_disconnect_and_put+0x2a/0x280 drivers/block/nbd.c:2293 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&nbd->config_lock){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x19d/0x1550 kernel/locking/mutex.c:821 refcount_dec_and_mutex_lock+0x30/0xa0 lib/refcount.c:118 nbd_config_put+0x2e/0x660 drivers/block/nbd.c:1471 recv_work+0x1d30/0x1e10 drivers/block/nbd.c:1026 process_one_work kernel/workqueue.c:3322 [inline] process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 -> #1 ((work_completion)(&args->work)){+.+.}-{0:0}: process_one_work kernel/workqueue.c:3298 [inline] process_scheduled_works+0xa58/0x14e0 kernel/workqueue.c:3405 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 -> #0 ((wq_completion)nbd0-recv){+.+.}-{0:0}: check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x1520/0x2cf0 kernel/locking/lockdep.c:5237 lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868 touch_wq_lockdep_map+0xcb/0x180 kernel/workqueue.c:4037 __flush_workqueue+0x148/0x1470 kernel/workqueue.c:4079 nbd_disconnect_and_put+0x95/0x280 drivers/block/nbd.c:2301 nbd_genl_disconnect+0x4af/0x590 drivers/block/nbd.c:2340 genl_family_rcv_msg_doit+0x233/0x340 net/netlink/genetlink.c:1114 genl_family_rcv_msg net/netlink/genetlink.c:1194 [inline] genl_rcv_msg+0x614/0x7a0 net/netlink/genetlink.c:1209 netlink_rcv_skb+0x226/0x4a0 net/netlink/af_netlink.c:2556 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] netlink_unicast+0x7bb/0x940 net/netlink/af_netlink.c:1345 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1900 sock_sendmsg_nosec+0x13a/0x180 net/socket.c:775 __sock_sendmsg net/socket.c:790 [inline] ____sys_sendmsg+0x54e/0x850 net/socket.c:2684 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2738 __sys_sendmsg net/socket.c:2770 [inline] __do_sys_sendmsg net/socket.c:2775 [inline] __se_sys_sendmsg net/socket.c:2773 [inline] __x64_sys_sendmsg+0x1b1/0x290 net/socket.c:2773 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Chain exists of: (wq_completion)nbd0-recv --> (work_completion)(&args->work) --> &nbd->config_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&nbd->config_lock); lock((work_completion)(&args->work)); lock(&nbd->config_lock); lock((wq_completion)nbd0-recv); *** DEADLOCK *** 3 locks held by syz.0.3313/21624: #0: ffffffff8fe5d528 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217 #1: ffffffff8fe5d360 (genl_mutex){+.+.}-{4:4}, at: genl_lock net/netlink/genetlink.c:35 [inline] #1: ffffffff8fe5d360 (genl_mutex){+.+.}-{4:4}, at: genl_op_lock net/netlink/genetlink.c:60 [inline] #1: ffffffff8fe5d360 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0 net/netlink/genetlink.c:1208 #2: ffff888026f42260 (&nbd->config_lock){+.+.}-{4:4}, at: nbd_disconnect_and_put+0x2a/0x280 drivers/block/nbd.c:2293 stack backtrace: CPU: 1 UID: 0 PID: 21624 Comm: syz.0.3313 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 Call Trace: <TASK> dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_circular_bug+0x2e1/0x300 kernel/locking/lockdep.c:2043 check_noncircular+0x12e/0x150 kernel/locking/lockdep.c:2175 check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x1520/0x2cf0 kernel/locking/lockdep.c:5237 lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868 touch_wq_lockdep_map+0xcb/0x180 kernel/workqueue.c:4037 __flush_workqueue+0x148/0x1470 kernel/workqueue.c:4079 nbd_disconnect_and_put+0x95/0x280 drivers/block/nbd.c:2301 nbd_genl_disconnect+0x4af/0x590 drivers/block/nbd.c:2340 genl_family_rcv_msg_doit+0x233/0x340 net/netlink/genetlink.c:1114 genl_family_rcv_msg net/netlink/genetlink.c:1194 [inline] genl_rcv_msg+0x614/0x7a0 net/netlink/genetlink.c:1209 netlink_rcv_skb+0x226/0x4a0 net/netlink/af_netlink.c:2556 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] netlink_unicast+0x7bb/0x940 net/netlink/af_netlink.c:1345 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1900 sock_sendmsg_nosec+0x13a/0x180 net/socket.c:775 __sock_sendmsg net/socket.c:790 [inline] ____sys_sendmsg+0x54e/0x850 net/socket.c:2684 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2738 __sys_sendmsg net/socket.c:2770 [inline] __do_sys_sendmsg net/socket.c:2775 [inline] __se_sys_sendmsg net/socket.c:2773 [inline] __x64_sys_sendmsg+0x1b1/0x290 net/socket.c:2773 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f25f3b9ce59 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f25f4973028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f25f3e15fa0 RCX: 00007f25f3b9ce59 RDX: 0000000004000810 RSI: 00002000000002c0 RDI: 0000000000000009 RBP: 00007f25f3c32e6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f25f3e16038 R14: 00007f25f3e15fa0 R15: 00007ffd58d7d478 </TASK>

Crashes (4):
Time	Kernel	Commit	Syzkaller	Config	Log	Report	VM info	Assets (help?)	Manager	Title
2026/06/28 15:08	upstream	780d569e6c4b	fb92f11c	.config	console log	report	info	[disk image] [vmlinux] [kernel image]	ci-upstream-kasan-gce-root	possible deadlock in nbd_disconnect_and_put
2026/07/07 23:49	upstream	0e35b9b6ec0f	88a4b44c	.config	console log	report	info	[disk image (non-bootable)] [vmlinux] [kernel image]	ci-qemu-upstream-386	possible deadlock in nbd_disconnect_and_put
2026/05/15 21:46	upstream	d458a240344c	81fb92f3	.config	console log	report	info	[disk image (non-bootable)] [vmlinux] [kernel image]	ci-qemu-upstream-386	possible deadlock in nbd_disconnect_and_put
2026/02/16 16:36	linux-next	635c467cc14e	5d52cba5	.config	console log	report	info	[disk image] [vmlinux] [kernel image]	ci-upstream-rust-kasan-gce	possible deadlock in nbd_disconnect_and_put

Crashes (4):

Assets (help?)