INFO: task syz-executor:6602 blocked in I/O wait for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:20840 pid:6602 tgid:6602 ppid:1 task_flags:0x400140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5387 [inline] __schedule+0x169e/0x54f0 kernel/sched/core.c:7188 __schedule_loop kernel/sched/core.c:7267 [inline] schedule+0x164/0x360 kernel/sched/core.c:7282 io_schedule+0x7f/0xd0 kernel/sched/core.c:8109 bit_wait_io+0x11/0xd0 kernel/sched/wait_bit.c:250 __wait_on_bit_lock+0xe3/0x4b0 kernel/sched/wait_bit.c:93 out_of_line_wait_on_bit_lock+0x13b/0x190 kernel/sched/wait_bit.c:120 lock_buffer include/linux/buffer_head.h:432 [inline] hfs_mdb_commit+0xce7/0x1150 fs/hfs/mdb.c:351 hfs_sync_fs+0x1d/0x30 fs/hfs/super.c:38 sync_filesystem+0xed/0x250 fs/sync.c:56 generic_shutdown_super+0x77/0x2d0 fs/super.c:625 kill_block_super+0x44/0x90 fs/super.c:1725 hfs_kill_super+0x41/0x50 fs/hfs/super.c:441 deactivate_locked_super+0xbc/0x130 fs/super.c:476 cleanup_mnt+0x437/0x4d0 fs/namespace.c:1312 task_work_run+0x1d9/0x270 kernel/task_work.c:233 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] __exit_to_user_mode_loop kernel/entry/common.c:67 [inline] exit_to_user_mode_loop+0xed/0x480 kernel/entry/common.c:98 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:328 [inline] do_syscall_64+0x33e/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f61d920c157 RSP: 002b:00007fff9842f2e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 00007f61d929f33b RCX: 00007f61d920c157 RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007fff9842f3a0 RBP: 00007fff9842f3a0 R08: 00007fff984303a0 R09: 00000000ffffffff R10: 0000000000000000 R11: 0000000000000246 R12: 00007fff98430430 R13: 00007f61d929f33b R14: 0000000000026c91 R15: 00007fff98430470 Showing all locks held in the system: 2 locks held by kworker/0:1/10: #0: ffff88813fe3b138 ((wq_completion)events_long){+.+.}-{0:0}, at: process_one_work+0x890/0x1710 kernel/workqueue.c:3284 #1: ffffc900000f7c40 ((work_completion)(&(&sbi->mdb_work)->work)){+.+.}-{0:0}, at: process_one_work+0x8b7/0x1710 kernel/workqueue.c:3285 1 lock held by khungtaskd/39: #0: ffffffff8dfc8100 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #0: ffffffff8dfc8100 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline] #0: ffffffff8dfc8100 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6777 2 locks held by kworker/0:2/821: #0: ffff88813fe3b138 ((wq_completion)events_long){+.+.}-{0:0}, at: process_one_work+0x890/0x1710 kernel/workqueue.c:3284 #1: ffffc90005377c40 ((work_completion)(&(&sbi->mdb_work)->work)){+.+.}-{0:0}, at: process_one_work+0x8b7/0x1710 kernel/workqueue.c:3285 2 locks held by kworker/1:3/1260: #0: ffff88813fe3b138 ((wq_completion)events_long){+.+.}-{0:0}, at: process_one_work+0x890/0x1710 kernel/workqueue.c:3284 #1: ffffc9000607fc40 ((work_completion)(&(&sbi->mdb_work)->work)){+.+.}-{0:0}, at: process_one_work+0x8b7/0x1710 kernel/workqueue.c:3285 2 locks held by getty/5579: #0: ffff888037ede0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc90003cbe2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x462/0x13a0 drivers/tty/n_tty.c:2211 2 locks held by kworker/1:4/5860: #0: ffff88813fe3b138 ((wq_completion)events_long){+.+.}-{0:0}, at: process_one_work+0x890/0x1710 kernel/workqueue.c:3284 #1: ffffc90004db7c40 ((work_completion)(&(&sbi->mdb_work)->work)){+.+.}-{0:0}, at: process_one_work+0x8b7/0x1710 kernel/workqueue.c:3285 2 locks held by kworker/0:4/5861: #0: ffff88813fe3b138 ((wq_completion)events_long){+.+.}-{0:0}, at: process_one_work+0x890/0x1710 kernel/workqueue.c:3284 #1: ffffc90004dc7c40 ((work_completion)(&(&sbi->mdb_work)->work)){+.+.}-{0:0}, at: process_one_work+0x8b7/0x1710 kernel/workqueue.c:3285 2 locks held by kworker/1:5/6118: #0: ffff88813fe3b138 ((wq_completion)events_long){+.+.}-{0:0}, at: process_one_work+0x890/0x1710 kernel/workqueue.c:3284 #1: ffffc90003e67c40 ((work_completion)(&(&sbi->mdb_work)->work)){+.+.}-{0:0}, at: process_one_work+0x8b7/0x1710 kernel/workqueue.c:3285 1 lock held by syz-executor/6602: #0: ffff88803ed8c0d0 (&type->s_umount_key#55){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff88803ed8c0d0 (&type->s_umount_key#55){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline] #0: ffff88803ed8c0d0 (&type->s_umount_key#55){+.+.}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:508 1 lock held by syz-executor/6762: #0: ffff8880607240d0 (&type->s_umount_key#55){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff8880607240d0 (&type->s_umount_key#55){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline] #0: ffff8880607240d0 (&type->s_umount_key#55){+.+.}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:508 1 lock held by syz-executor/6790: #0: ffff88802a6f00d0 (&type->s_umount_key#55){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff88802a6f00d0 (&type->s_umount_key#55){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline] #0: ffff88802a6f00d0 (&type->s_umount_key#55){+.+.}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:508 2 locks held by kworker/1:6/6810: #0: ffff88813fe3b138 ((wq_completion)events_long){+.+.}-{0:0}, at: process_one_work+0x890/0x1710 kernel/workqueue.c:3284 #1: ffffc90003f47c40 ((work_completion)(&(&sbi->mdb_work)->work)){+.+.}-{0:0}, at: process_one_work+0x8b7/0x1710 kernel/workqueue.c:3285 1 lock held by syz-executor/6814: #0: ffff88803b0020d0 (&type->s_umount_key#55){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff88803b0020d0 (&type->s_umount_key#55){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline] #0: ffff88803b0020d0 (&type->s_umount_key#55){+.+.}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:508 2 locks held by kworker/1:7/6836: #0: ffff88813fe3b138 ((wq_completion)events_long){+.+.}-{0:0}, at: process_one_work+0x890/0x1710 kernel/workqueue.c:3284 #1: ffffc90004067c40 ((work_completion)(&(&sbi->mdb_work)->work)){+.+.}-{0:0}, at: process_one_work+0x8b7/0x1710 kernel/workqueue.c:3285 1 lock held by syz-executor/6840: #0: ffff88805e3b40d0 (&type->s_umount_key#55){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff88805e3b40d0 (&type->s_umount_key#55){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline] #0: ffff88805e3b40d0 (&type->s_umount_key#55){+.+.}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:508 1 lock held by syz-executor/6876: #0: ffff88805fa960d0 (&type->s_umount_key#55){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff88805fa960d0 (&type->s_umount_key#55){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline] #0: ffff88805fa960d0 (&type->s_umount_key#55){+.+.}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:508 1 lock held by syz-executor/6906: #0: ffff8880250780d0 ( &type->s_umount_key#55){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline] &type->s_umount_key#55){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline] &type->s_umount_key#55){+.+.}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:508 1 lock held by syz-executor/6936: #0: ffff88803b0080d0 (&type->s_umount_key#55){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff88803b0080d0 (&type->s_umount_key#55){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline] #0: ffff88803b0080d0 (&type->s_umount_key#55){+.+.}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:508 2 locks held by syz-executor/6966: #0: ffffffff8f37fff8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #0: ffffffff8f37fff8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #0: ffffffff8f37fff8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x883/0x1bb0 net/core/rtnetlink.c:4107 #1: ffffffff8dfc8100 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #1: ffffffff8dfc8100 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline] #1: ffffffff8dfc8100 (rcu_read_lock){....}-{1:3}, at: __queue_work+0x1cf/0x1010 kernel/workqueue.c:2301 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 39 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline] __sys_info lib/sys_info.c:157 [inline] sys_info+0x135/0x170 lib/sys_info.c:165 check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline] watchdog+0xfd3/0x1030 kernel/hung_task.c:561 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 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 6966 Comm: syz-executor Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 RIP: 0010:caif_device_notify+0xc73/0x1000 include/linux/rcupdate.h:-1 Code: c7 60 7d 75 8c be 64 03 00 00 48 c7 c2 00 7e 75 8c e8 c1 7b bb f6 48 c7 c7 00 81 fc 8d 48 89 ee e8 42 62 bb f6 e8 1d 24 c5 f6 <31> c0 65 48 8b 0d 83 da 90 07 48 3b 4c 24 58 0f 85 b5 02 00 00 48 RSP: 0018:ffffc900053f6bf8 EFLAGS: 00000293 RAX: ffffffff8ae52b6e RBX: 0000000000000001 RCX: ffff8880397a5c40 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffff88805c7d0108 R08: 0000000000000000 R09: 0000000000000000 R10: dffffc0000000000 R11: ffffffff8ae52920 R12: 1ffff1100b8fa021 R13: ffff88805c7d0108 R14: ffff88805c7d0000 R15: dffffc0000000000 FS: 000055556a6c4500(0000) GS:ffff888125fbf000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f09094c5000 CR3: 0000000039e30000 CR4: 00000000003526f0 Call Trace: notifier_call_chain+0x1ad/0x3d0 kernel/notifier.c:85 call_netdevice_notifiers_extack net/core/dev.c:2288 [inline] call_netdevice_notifiers+0x90/0xd0 net/core/dev.c:2302 br_add_if+0x2fb/0xed0 net/bridge/br_if.c:590 do_set_master+0x533/0x6d0 net/core/rtnetlink.c:2985 do_setlink+0x1018/0x4590 net/core/rtnetlink.c:3187 rtnl_changelink net/core/rtnetlink.c:3798 [inline] __rtnl_newlink net/core/rtnetlink.c:3971 [inline] rtnl_newlink+0x15ad/0x1bb0 net/core/rtnetlink.c:4108 rtnetlink_rcv_msg+0x7d5/0xbe0 net/core/rtnetlink.c:6994 netlink_rcv_skb+0x232/0x4b0 net/netlink/af_netlink.c:2550 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x780/0x920 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec+0x112/0x150 net/socket.c:797 __sock_sendmsg net/socket.c:812 [inline] __sys_sendto+0x402/0x590 net/socket.c:2280 __do_sys_sendto net/socket.c:2287 [inline] __se_sys_sendto net/socket.c:2283 [inline] __x64_sys_sendto+0xde/0x100 net/socket.c:2283 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f09086eb7ce Code: 08 0f 85 a5 a8 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08 RSP: 002b:00007ffe467b01b8 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 000055556a6c4500 RCX: 00007f09086eb7ce RDX: 0000000000000028 RSI: 00007f09094c4670 RDI: 0000000000000003 RBP: 0000000000000001 R08: 00007ffe467b0234 R09: 000000000000000c R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003 R13: 0000000000000000 R14: 00007f09094c4670 R15: 0000000000000000 ---------------- Code disassembly (best guess), 2 bytes skipped: 0: 7d 75 jge 0x77 2: 8c be 64 03 00 00 mov %?,0x364(%rsi) 8: 48 c7 c2 00 7e 75 8c mov $0xffffffff8c757e00,%rdx f: e8 c1 7b bb f6 call 0xf6bb7bd5 14: 48 c7 c7 00 81 fc 8d mov $0xffffffff8dfc8100,%rdi 1b: 48 89 ee mov %rbp,%rsi 1e: e8 42 62 bb f6 call 0xf6bb6265 23: e8 1d 24 c5 f6 call 0xf6c52445 * 28: 31 c0 xor %eax,%eax <-- trapping instruction 2a: 65 48 8b 0d 83 da 90 mov %gs:0x790da83(%rip),%rcx # 0x790dab5 31: 07 32: 48 3b 4c 24 58 cmp 0x58(%rsp),%rcx 37: 0f 85 b5 02 00 00 jne 0x2f2 3d: 48 rex.W