INFO: task syz.0.451:7798 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.0.451 state:D stack:27656 pid:7798 tgid:7796 ppid:5851 task_flags:0x400140 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1190/0x5de0 kernel/sched/core.c:6961 __schedule_loop kernel/sched/core.c:7043 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:7058 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7115 __mutex_lock_common kernel/locking/mutex.c:676 [inline] __mutex_lock+0x81b/0x1060 kernel/locking/mutex.c:760 bdev_open+0x41a/0xe40 block/bdev.c:945 blkdev_open+0x34e/0x4f0 block/fops.c:694 do_dentry_open+0x982/0x1530 fs/open.c:965 vfs_open+0x82/0x3f0 fs/open.c:1095 do_open fs/namei.c:3887 [inline] path_openat+0x1de4/0x2cb0 fs/namei.c:4046 do_filp_open+0x20b/0x470 fs/namei.c:4073 do_sys_openat2+0x11b/0x1d0 fs/open.c:1435 do_sys_open fs/open.c:1450 [inline] __do_sys_openat fs/open.c:1466 [inline] __se_sys_openat fs/open.c:1461 [inline] __x64_sys_openat+0x174/0x210 fs/open.c:1461 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f5e3138d510 RSP: 002b:00007f5e321b1b70 EFLAGS: 00000293 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 0000000000020002 RCX: 00007f5e3138d510 RDX: 0000000000020002 RSI: 00007f5e321b1c10 RDI: 00000000ffffff9c RBP: 00007f5e321b1c10 R08: 0000000000000000 R09: 002364626e2f7665 R10: 0000000000000000 R11: 0000000000000293 R12: cccccccccccccccd R13: 00007f5e315d6038 R14: 00007f5e315d5fa0 R15: 00007ffd468be978 Showing all locks held in the system: 1 lock held by khungtaskd/31: #0: ffffffff8e5c1260 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8e5c1260 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8e5c1260 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6775 2 locks held by getty/5605: #0: ffff88814e0380a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x14f0 drivers/tty/n_tty.c:2222 1 lock held by udevd/5845: #0: ffff888142793358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0x41a/0xe40 block/bdev.c:945 1 lock held by syz.0.451/7798: #0: ffff888142793358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0x41a/0xe40 block/bdev.c:945 6 locks held by syz.3.714/8930: #0: ffff8880772b2ef8 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x2a2/0x370 fs/file.c:1232 #1: ffff888036574428 (sb_writers#8){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:738 #2: ffff888035ed9488 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x28f/0x510 fs/kernfs/file.c:325 #3: ffff888141ee71e8 (kn->active#62){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x2b2/0x510 fs/kernfs/file.c:326 #4: ffffffff8e4849c8 (system_transition_mutex){+.+.}-{4:4}, at: software_resume+0x65/0x4e0 kernel/power/hibernate.c:1038 #5: ffff888142793358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xa2/0xe40 block/bdev.c:945 1 lock held by syz-executor/9116: #0: ffffffff8f304228 (misc_mtx){+.+.}-{4:4}, at: misc_open+0x63/0x420 drivers/char/misc.c:125 2 locks held by syz.1.777/9186: #0: ffffffff8f304228 (misc_mtx){+.+.}-{4:4}, at: misc_open+0x63/0x420 drivers/char/misc.c:125 #1: ffffffff8e4849c8 (system_transition_mutex){+.+.}-{4:4}, at: lock_system_sleep+0x87/0xa0 kernel/power/main.c:57 1 lock held by syz.4.781/9208: #0: ffffffff8f304228 (misc_mtx){+.+.}-{4:4}, at: misc_open+0x63/0x420 drivers/char/misc.c:125 1 lock held by syz.2.782/9224: #0: ffffffff8f304228 (misc_mtx){+.+.}-{4:4}, at: misc_open+0x63/0x420 drivers/char/misc.c:125 1 lock held by syz.5.784/9233: #0: ffffffff8f304228 (misc_mtx){+.+.}-{4:4}, at: misc_open+0x63/0x420 drivers/char/misc.c:125 1 lock held by syz-executor/9241: #0: ffffffff8f304228 (misc_mtx){+.+.}-{4:4}, at: misc_open+0x63/0x420 drivers/char/misc.c:125 1 lock held by syz-executor/9243: #0: ffffffff8f304228 (misc_mtx){+.+.}-{4:4}, at: misc_open+0x63/0x420 drivers/char/misc.c:125 1 lock held by syz-executor/9245: #0: ffffffff8f304228 (misc_mtx){+.+.}-{4:4}, at: misc_open+0x63/0x420 drivers/char/misc.c:125 1 lock held by syz-executor/9247: #0: ffffffff8f304228 (misc_mtx){+.+.}-{4:4}, at: misc_open+0x63/0x420 drivers/char/misc.c:125 1 lock held by syz-executor/9249: #0: ffffffff8f304228 (misc_mtx){+.+.}-{4:4}, at: misc_open+0x63/0x420 drivers/char/misc.c:125 ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:328 [inline] watchdog+0xf0e/0x1260 kernel/hung_task.c:491 kthread+0x3c2/0x780 kernel/kthread.c:463 ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:82 Code: cc 61 02 c3 cc cc cc cc 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 53 b3 15 00 fb f4 8c 09 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90 RSP: 0018:ffffffff8e207e08 EFLAGS: 000002c2 RAX: 0000000000f36243 RBX: 0000000000000000 RCX: ffffffff8b945c29 RDX: 0000000000000000 RSI: ffffffff8de522e8 RDI: ffffffff8c162d80 RBP: fffffbfff1c52ef8 R08: 0000000000000001 R09: ffffed1017086655 R10: ffff8880b84332ab R11: 0000000000000000 R12: 0000000000000000 R13: ffffffff8e2977c0 R14: ffffffff90ab6b90 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8881246b5000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055980d710b48 CR3: 000000000e380000 CR4: 00000000003526f0 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:757 default_idle_call+0x6d/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:190 [inline] do_idle+0x391/0x510 kernel/sched/idle.c:330 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:428 rest_init+0x16b/0x2b0 init/main.c:744 start_kernel+0x3ee/0x4d0 init/main.c:1097 x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:307 x86_64_start_kernel+0x130/0x190 arch/x86/kernel/head64.c:288 common_startup_64+0x13e/0x148