INFO: task syz.9.2599:14035 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.9.2599 state:D stack:27472 pid:14035 ppid:12544 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x1553/0x45a0 kernel/sched/core.c:6700 schedule+0xbd/0x170 kernel/sched/core.c:6774 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6833 __mutex_lock_common kernel/locking/mutex.c:679 [inline] __mutex_lock+0x6a9/0xcc0 kernel/locking/mutex.c:747 sync_bdevs+0x1af/0x330 block/bdev.c:1076 ksys_sync+0xc6/0x170 fs/sync.c:105 __ia32_sys_sync+0xe/0x20 fs/sync.c:113 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fb89ad9aeb9 RSP: 002b:00007fb89bc9a028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2 RAX: ffffffffffffffda RBX: 00007fb89b016090 RCX: 00007fb89ad9aeb9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007fb89b016090 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fb89b016128 R14: 00007fb89b016090 R15: 00007ffc98fcc608 Showing all locks held in the system: 1 lock held by khungtaskd/29: #0: ffffffff8d131fe0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline] #0: ffffffff8d131fe0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline] #0: ffffffff8d131fe0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x290 kernel/locking/lockdep.c:6633 2 locks held by kworker/u4:6/1094: 2 locks held by getty/5529: #0: ffff888031e320a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000326e2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x433/0x1390 drivers/tty/n_tty.c:2217 1 lock held by udevd/5785: #0: ffff8880222194c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x121/0x600 block/bdev.c:805 2 locks held by kworker/1:5/5863: #0: ffff888017c72538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline] #0: ffff888017c72538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_scheduled_works+0x96f/0x15d0 kernel/workqueue.c:2711 #1: ffffc9000522fd00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline] #1: ffffc9000522fd00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_scheduled_works+0x96f/0x15d0 kernel/workqueue.c:2711 1 lock held by udevd/5962: #0: ffff8880221e34c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x121/0x600 block/bdev.c:805 1 lock held by syz-executor/12448: #0: ffffffff8d1379b8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:324 [inline] #0: ffffffff8d1379b8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x3da/0x880 kernel/rcu/tree_exp.h:1004 1 lock held by syz.9.2599/14035: #0: ffff8880221e34c8 (&disk->open_mutex){+.+.}-{3:3}, at: sync_bdevs+0x1af/0x330 block/bdev.c:1076 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 29 Comm: khungtaskd Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106 nmi_cpu_backtrace+0x3a6/0x3e0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/0x2f0 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline] watchdog+0xf3d/0xf80 kernel/hung_task.c:379 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 7102 Comm: udevd Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:check_kcov_mode kernel/kcov.c:184 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x30/0x60 kernel/kcov.c:216 Code: 04 24 65 48 8b 0d 90 a2 7c 7e 65 8b 15 91 a2 7c 7e 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 1c 16 00 00 00 74 2c <8b> 91 f8 15 00 00 83 fa 02 75 21 48 8b 91 00 16 00 00 48 8b 32 48 RSP: 0018:ffffc90003367830 EFLAGS: 00000246 RAX: ffffffff8a710d6d RBX: 0000000000000001 RCX: ffff888024d23c00 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: 0000000000000001 R08: ffff888024d23c00 R09: 0000000000000003 R10: 0000000000000002 R11: 0000000000000000 R12: 0000000000000000 R13: dffffc0000000000 R14: ffff88801f70c000 R15: ffff88802d4eb120 FS: 00007fd687bf4880(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fd687bda000 CR3: 00000000619e4000 CR4: 00000000003506e0 Call Trace: mt_slot lib/maple_tree.c:814 [inline] mas_next_slot+0x76d/0x980 lib/maple_tree.c:4667 vma_next include/linux/mm.h:967 [inline] validate_mm+0x317/0x450 mm/mmap.c:289 vma_merge+0x1ac7/0x20e0 mm/mmap.c:1035 mprotect_fixup+0x489/0xca0 mm/mprotect.c:632 do_mprotect_pkey+0x7c2/0xcb0 mm/mprotect.c:819 __do_sys_mprotect mm/mprotect.c:840 [inline] __se_sys_mprotect mm/mprotect.c:837 [inline] __x64_sys_mprotect+0x80/0x90 mm/mprotect.c:837 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fd68751dfe7 Code: ef e8 3d fa ff ff 84 c0 75 b9 31 db 48 83 c4 08 48 89 d8 5b 5d 41 5c 41 5d 41 5e 41 5f c3 0f 1f 44 00 00 b8 0a 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d e1 2d 0d 00 f7 d8 64 89 01 48 RSP: 002b:00007ffe55396318 EFLAGS: 00000246 ORIG_RAX: 000000000000000a RAX: ffffffffffffffda RBX: 0000000000000200 RCX: 00007fd68751dfe7 RDX: 0000000000000001 RSI: 0000000000000200 RDI: 00007fd687bda000 RBP: 000055eeb9f944c0 R08: 0000000000000000 R09: 0000000000000200 R10: 000055eeb9f94520 R11: 0000000000000246 R12: 000000000000003c R13: 0000000000fff000 R14: 000055eeb9f93bb8 R15: 00007fd687d1b39c