INFO: task syz.4.31:6111 blocked for more than 143 seconds. Not tainted syzkaller #0 Blocked by coredump. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.4.31 state:D stack:25984 pid:6111 tgid:6111 ppid:5974 task_flags:0x40014c flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x14bc/0x5000 kernel/sched/core.c:6863 __schedule_loop kernel/sched/core.c:6945 [inline] schedule+0x165/0x360 kernel/sched/core.c:6960 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7017 rwsem_down_write_slowpath+0x872/0xfe0 kernel/locking/rwsem.c:1185 __down_write_common kernel/locking/rwsem.c:1317 [inline] __down_write kernel/locking/rwsem.c:1326 [inline] down_write+0x1ab/0x1f0 kernel/locking/rwsem.c:1591 mmap_write_lock include/linux/mmap_lock.h:312 [inline] exit_mmap+0x281/0xb20 mm/mmap.c:1288 __mmput+0x118/0x430 kernel/fork.c:1130 exit_mm+0x1da/0x2c0 kernel/exit.c:583 do_exit+0x658/0x2310 kernel/exit.c:961 do_group_exit+0x21c/0x2d0 kernel/exit.c:1114 __do_sys_exit_group kernel/exit.c:1125 [inline] __se_sys_exit_group kernel/exit.c:1123 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1123 x64_sys_call+0x2210/0x2210 arch/x86/include/generated/asm/syscalls_64.h:232 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f4cfdd8f749 RSP: 002b:00007fff0a9ec858 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f4cfdd8f749 RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007fff0a9ec8bc R08: 000000050a9ec94f R09: 00000000000927c0 R10: 0000000000000001 R11: 0000000000000246 R12: 000000000000000a R13: 00000000000927c0 R14: 00000000000271f5 R15: 00007fff0a9ec910 Showing all locks held in the system: 1 lock held by khungtaskd/31: #0: ffffffff8df41cc0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8df41cc0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #0: ffffffff8df41cc0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 2 locks held by udevd/5202: #0: ffffffff8dffdcf0 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mm kernel/fork.c:1485 [inline] #0: ffffffff8dffdcf0 (dup_mmap_sem){.+.+}-{0:0}, at: copy_mm+0x131/0x4b0 kernel/fork.c:1538 #1: ffff88807c253440 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:330 [inline] #1: ffff88807c253440 (&mm->mmap_lock){++++}-{4:4}, at: dup_mmap+0x126/0x1b10 mm/mmap.c:1727 2 locks held by getty/5597: #0: ffff88814d0710a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222 1 lock held by syz-executor/5966: #0: ffff88807c53d900 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:312 [inline] #0: ffff88807c53d900 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x281/0xb20 mm/mmap.c:1288 1 lock held by syz-executor/5969: #0: ffff88807c53e540 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:312 [inline] #0: ffff88807c53e540 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x281/0xb20 mm/mmap.c:1288 1 lock held by syz-executor/5973: #0: ffff88802369b440 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:312 [inline] #0: ffff88802369b440 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x281/0xb20 mm/mmap.c:1288 1 lock held by syz-executor/5974: #0: ffff88807c538340 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:312 [inline] #0: ffff88807c538340 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x281/0xb20 mm/mmap.c:1288 1 lock held by syz-executor/5978: #0: ffff888023699bc0 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:312 [inline] #0: ffff888023699bc0 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x281/0xb20 mm/mmap.c:1288 1 lock held by syz.4.31/6111: #0: ffff888079786540 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:312 [inline] #0: ffff888079786540 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x281/0xb20 mm/mmap.c:1288 1 lock held by syz-executor/6114: #0: ffff888079783440 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:312 [inline] #0: ffff888079783440 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x281/0xb20 mm/mmap.c:1288 1 lock held by syz-executor/6120: #0: ffff88802f4fb440 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:312 [inline] #0: ffff88802f4fb440 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x281/0xb20 mm/mmap.c:1288 1 lock held by syz-executor/6123: #0: ffff888079781bc0 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:312 [inline] #0: ffff888079781bc0 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x281/0xb20 mm/mmap.c:1288 1 lock held by syz-executor/6124: #0: ffff88802f4fd900 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:312 [inline] #0: ffff88802f4fd900 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x281/0xb20 mm/mmap.c:1288 1 lock held by udevd/6162: #0: ffff8880312b8f80 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:330 [inline] #0: ffff8880312b8f80 (&mm->mmap_lock){++++}-{4:4}, at: __vm_munmap+0x136/0x380 mm/vma.c:3153 1 lock held by syz.7.35/6267: #0: ffff88807c254080 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:312 [inline] #0: ffff88807c254080 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x281/0xb20 mm/mmap.c:1288 1 lock held by syz.5.47/6268: #0: ffff88803308ccc0 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:312 [inline] #0: ffff88803308ccc0 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x281/0xb20 mm/mmap.c:1288 1 lock held by syz.9.63/6291: #0: ffff88807b426540 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:312 [inline] #0: ffff88807b426540 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x281/0xb20 mm/mmap.c:1288 1 lock held by syz.8.64/6292: #0: ffff88807b424cc0 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:312 [inline] #0: ffff88807b424cc0 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x281/0xb20 mm/mmap.c:1288 2 locks held by kworker/u8:21/6294: #0: ffff88801a069148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3232 [inline] #0: ffff88801a069148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x1770 kernel/workqueue.c:3340 #1: ffffc90002f67b80 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3233 [inline] #1: ffffc90002f67b80 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x1770 kernel/workqueue.c:3340 1 lock held by syz-executor/6298: #0: ffff8880312bc080 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:312 [inline] #0: ffff8880312bc080 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x281/0xb20 mm/mmap.c:1288 1 lock held by syz-executor/6300: #0: ffff88807b422800 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:312 [inline] #0: ffff88807b422800 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x281/0xb20 mm/mmap.c:1288 1 lock held by syz-executor/6302: #0: ffff88802369c080 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:312 [inline] #0: ffff88802369c080 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x281/0xb20 mm/mmap.c:1288 1 lock held by syz-executor/6323: #0: ffff8880312ba800 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:312 [inline] #0: ffff8880312ba800 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x281/0xb20 mm/mmap.c:1288 1 lock held by modprobe/6424: #0: ffff888028434cc0 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:330 [inline] #0: ffff888028434cc0 (&mm->mmap_lock){++++}-{4:4}, at: vm_mmap_pgoff+0x211/0x4d0 mm/util.c:579 1 lock held by syz.0.93/6425: #0: ffff888028434080 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:312 [inline] #0: ffff888028434080 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x281/0xb20 mm/mmap.c:1288 2 locks held by kworker/u8:26/6426: #0: ffff88801a069148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3232 [inline] #0: ffff88801a069148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x1770 kernel/workqueue.c:3340 #1: ffffc9000b557b80 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3233 [inline] #1: ffffc9000b557b80 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x1770 kernel/workqueue.c:3340 1 lock held by syz-executor/6878: #0: ffff888034330f80 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:312 [inline] #0: ffff888034330f80 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x281/0xb20 mm/mmap.c:1288 1 lock held by syz.1.638/7040: #0: ffff8880585f6540 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:312 [inline] #0: ffff8880585f6540 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x281/0xb20 mm/mmap.c:1288 1 lock held by modprobe/7041: #0: ffff88805b5c8f80 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:330 [inline] #0: ffff88805b5c8f80 (&mm->mmap_lock){++++}-{4:4}, at: vm_mmap_pgoff+0x211/0x4d0 mm/util.c:579 1 lock held by syz.7.658/7070: #0: ffff88805478ccc0 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:312 [inline] #0: ffff88805478ccc0 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x281/0xb20 mm/mmap.c:1288 1 lock held by syz-executor/7495: #0: ffff888033db7180 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:312 [inline] #0: ffff888033db7180 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x281/0xb20 mm/mmap.c:1288 1 lock held by syz-executor/7527: #0: ffff88801c71d900 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:312 [inline] #0: ffff88801c71d900 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x281/0xb20 mm/mmap.c:1288 1 lock held by syz.5.1173/7642: #0: ffff888055cc9bc0 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:312 [inline] #0: ffff888055cc9bc0 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x281/0xb20 mm/mmap.c:1288 2 locks held by syz-executor/7683: #0: ffffffff8dffdcf0 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mm kernel/fork.c:1485 [inline] #0: ffffffff8dffdcf0 (dup_mmap_sem){.+.+}-{0:0}, at: copy_mm+0x131/0x4b0 kernel/fork.c:1538 #1: ffff88807c255900 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:330 [inline] #1: ffff88807c255900 (&mm->mmap_lock){++++}-{4:4}, at: dup_mmap+0x126/0x1b10 mm/mmap.c:1727 1 lock held by syz-executor/7688: #0: ffff88807bf14cc0 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:312 [inline] #0: ffff88807bf14cc0 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x281/0xb20 mm/mmap.c:1288 1 lock held by syz-executor/7694: #0: ffff88802f4fc080 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:312 [inline] #0: ffff88802f4fc080 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x281/0xb20 mm/mmap.c:1288 1 lock held by syz.4.1285/7841: #0: ffff88801a059bc0 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:312 [inline] #0: ffff88801a059bc0 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x281/0xb20 mm/mmap.c:1288 2 locks held by syz-executor/8236: #0: ffffffff8dffdcf0 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mm kernel/fork.c:1485 [inline] #0: ffffffff8dffdcf0 (dup_mmap_sem){.+.+}-{0:0}, at: copy_mm+0x131/0x4b0 kernel/fork.c:1538 #1: ffff88802893c080 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:330 [inline] #1: ffff88802893c080 (&mm->mmap_lock){++++}-{4:4}, at: dup_mmap+0x126/0x1b10 mm/mmap.c:1727 2 locks held by syz-executor/8267: #0: ffffffff8dffdcf0 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mm kernel/fork.c:1485 [inline] #0: ffffffff8dffdcf0 (dup_mmap_sem){.+.+}-{0:0}, at: copy_mm+0x131/0x4b0 kernel/fork.c:1538 #1: ffff888055c3a800 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:330 [inline] #1: ffff888055c3a800 (&mm->mmap_lock){++++}-{4:4}, at: dup_mmap+0x126/0x1b10 mm/mmap.c:1727 1 lock held by syz.6.1774/8414: #0: ffff888055c3c080 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:312 [inline] #0: ffff888055c3c080 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x281/0xb20 mm/mmap.c:1288 2 locks held by syz.7.2017/8681: #0: ffffffff8df991e8 (tracepoints_mutex){+.+.}-{4:4}, at: tracepoint_probe_register_prio_may_exist+0x43/0xa0 kernel/tracepoint.c:431 #1: ffffffff8df477f8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:311 [inline] #1: ffffffff8df477f8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2f6/0x730 kernel/rcu/tree_exp.h:956 ============================================= 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 10/25/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:332 [inline] watchdog+0xf3c/0xf80 kernel/hung_task.c:495 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 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 10/25/2025 RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82 Code: 53 ec 02 00 cc cc cc 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 0d 1f 00 f3 0f 1e fa fb f4 cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffffff8dc07d80 EFLAGS: 000002c6 RAX: 912a7d635f7c9700 RBX: ffffffff8197438a RCX: 912a7d635f7c9700 RDX: 0000000000000001 RSI: ffffffff8d76bd39 RDI: ffffffff8bbfc660 RBP: ffffffff8dc07ea8 R08: ffff8880b883359b R09: 1ffff110171066b3 R10: dffffc0000000000 R11: ffffed10171066b4 R12: ffffffff8f805a70 R13: 1ffffffff1b92a50 R14: 0000000000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8881260b1000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 000000002682a000 CR4: 00000000003526f0 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:767 default_idle_call+0x73/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:191 [inline] do_idle+0x1ea/0x520 kernel/sched/idle.c:332 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:430 rest_init+0x2de/0x300 init/main.c:757 start_kernel+0x3ae/0x410 init/main.c:1111 x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310 x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291 common_startup_64+0x13e/0x147