INFO: task syz.8.3628:17225 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.8.3628 state:D stack:26424 pid:17225 tgid:17219 ppid:8906 task_flags:0x400740 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5258 [inline] __schedule+0x150e/0x5070 kernel/sched/core.c:6866 __schedule_loop kernel/sched/core.c:6948 [inline] schedule+0x165/0x360 kernel/sched/core.c:6963 schedule_timeout+0x9a/0x270 kernel/time/sleep_timeout.c:75 do_wait_for_common kernel/sched/completion.c:100 [inline] __wait_for_common+0x3da/0x710 kernel/sched/completion.c:121 wait_for_common kernel/sched/completion.c:132 [inline] wait_for_completion_state+0x1c/0x40 kernel/sched/completion.c:269 coredump_wait fs/coredump.c:534 [inline] vfs_coredump+0x94b/0x3e60 fs/coredump.c:1196 get_signal+0x1108/0x1340 kernel/signal.c:3019 arch_do_signal_or_restart+0x9a/0x7a0 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:41 [inline] exit_to_user_mode_loop+0x87/0x4f0 kernel/entry/common.c:75 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline] do_syscall_64+0x2d0/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f18a498f749 RSP: 002b:00007f18a589e0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: ffffffffffffffda RBX: 00007f18a4be6188 RCX: 00007f18a498f749 RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007f18a4be618c RBP: 00007f18a4be6180 R08: 3fffffffffffffff R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f18a4be6218 R14: 00007ffc6d18d560 R15: 00007ffc6d18d648 Showing all locks held in the system: 1 lock held by khungtaskd/31: #0: ffffffff8e13f2e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8e13f2e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #0: ffffffff8e13f2e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 5 locks held by kworker/u8:4/61: 2 locks held by kworker/u8:6/141: #0: ffff8881456aa148 ((wq_completion)iou_exit){+.+.}-{0:0}, at: process_one_work+0x841/0x15a0 kernel/workqueue.c:3254 #1: ffffc90002e77b80 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_one_work+0x868/0x15a0 kernel/workqueue.c:3255 2 locks held by getty/5585: #0: ffff8880312b30a0 (&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+0x449/0x1460 drivers/tty/n_tty.c:2211 2 locks held by syz.4.4217/19246: ============================================= NMI backtrace for cpu 0 CPU: 0 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] __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:363 [inline] watchdog+0xe40/0xe90 kernel/hung_task.c:557 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 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 19246 Comm: syz.4.4217 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:__up_write kernel/locking/rwsem.c:1386 [inline] RIP: 0010:up_write+0x19e/0x410 kernel/locking/rwsem.c:1643 Code: 08 4c 89 f7 e8 33 5d 8a 00 48 c7 43 08 00 00 00 00 48 89 df be 08 00 00 00 e8 ce 5e 8a 00 48 c7 c0 ff ff ff ff f0 48 0f c1 03 02 75 29 bf 01 00 00 00 e8 04 06 f3 ff 65 8b 05 5d ab 01 11 85 RSP: 0018:ffffc9000ba4ea30 EFLAGS: 00000257 RAX: 0000000000000001 RBX: ffff8880281615c0 RCX: ffffffff819e04b2 RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffff8880281615c0 RBP: ffff888028161628 R08: ffff8880281615c7 R09: 1ffff1100502c2b8 R10: dffffc0000000000 R11: ffffed100502c2b9 R12: ffff8880281615c8 R13: dffffc0000000000 R14: ffff8880281615c8 R15: 1ffff1100502c2b9 FS: 00007f4b2fdf66c0(0000) GS:ffff888125d25000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fb7fedbd000 CR3: 000000005db00000 CR4: 00000000003526f0 DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000083 DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: inode_unlock include/linux/fs.h:1038 [inline] shmem_file_write_iter+0x103/0x120 mm/shmem.c:3504 __kernel_write_iter+0x428/0x910 fs/read_write.c:619 dump_emit_page fs/coredump.c:1298 [inline] dump_user_range+0x8a0/0xc90 fs/coredump.c:1372 elf_core_dump+0x3369/0x3960 fs/binfmt_elf.c:2111 coredump_write+0x1121/0x18b0 fs/coredump.c:1049 do_coredump fs/coredump.c:1126 [inline] vfs_coredump+0x3321/0x3e60 fs/coredump.c:1200 get_signal+0x1108/0x1340 kernel/signal.c:3019 arch_do_signal_or_restart+0x9a/0x7a0 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:41 [inline] exit_to_user_mode_loop kernel/entry/common.c:75 [inline] __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:270 [inline] irqentry_exit_to_user_mode include/linux/irq-entry-common.h:339 [inline] irqentry_exit+0x177/0x660 kernel/entry/common.c:196 exc_general_protection+0x171/0x1f0 arch/x86/kernel/traps.c:913 asm_exc_general_protection+0x26/0x30 arch/x86/include/asm/idtentry.h:612 RIP: 0033:0x7f4b31b8f751 Code: 00 00 00 00 00 0f 1f 40 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 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f RSP: 002b:0000200000000430 EFLAGS: 00010217 RAX: 0000000000000000 RBX: 00007f4b31de5fa0 RCX: 00007f4b31b8f749 RDX: 0000200000000440 RSI: 0000200000000430 RDI: 0000000000100000 RBP: 00007f4b31c13f91 R08: 00002000000004c0 R09: 00002000000004c0 R10: 0000200000000480 R11: 0000000000000206 R12: 0000000000000000 R13: 00007f4b31de6038 R14: 00007f4b31de5fa0 R15: 00007fff15e572a8