INFO: task syz.0.17:6474 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.0.17 state:D stack:26376 pid:6474 tgid:6474 ppid:6371 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929 __schedule_loop kernel/sched/core.c:7011 [inline] schedule+0x165/0x360 kernel/sched/core.c:7026 io_schedule+0x80/0xd0 kernel/sched/core.c:7871 folio_wait_bit_common+0x6b0/0xb80 mm/filemap.c:1330 folio_lock include/linux/pagemap.h:1141 [inline] writeback_get_folio mm/page-writeback.c:2468 [inline] writeback_iter+0x8d8/0x12a0 mm/page-writeback.c:2562 iomap_writepages+0x14d/0x2d0 fs/iomap/buffered-io.c:1769 gfs2_writepages+0x177/0x250 fs/gfs2/aops.c:175 do_writepages+0x32e/0x550 mm/page-writeback.c:2604 filemap_fdatawrite_wbc mm/filemap.c:389 [inline] __filemap_fdatawrite_range mm/filemap.c:422 [inline] __filemap_fdatawrite mm/filemap.c:428 [inline] filemap_fdatawrite+0x199/0x240 mm/filemap.c:433 gfs2_ordered_write fs/gfs2/log.c:733 [inline] gfs2_log_flush+0x966/0x24c0 fs/gfs2/log.c:1102 gfs2_trans_end+0x37c/0x570 fs/gfs2/trans.c:158 gfs2_page_mkwrite+0x14a8/0x1910 fs/gfs2/file.c:535 do_page_mkwrite+0x14d/0x310 mm/memory.c:3488 do_shared_fault mm/memory.c:5774 [inline] do_fault mm/memory.c:5836 [inline] do_pte_missing mm/memory.c:4361 [inline] handle_pte_fault mm/memory.c:6177 [inline] __handle_mm_fault+0x1916/0x5400 mm/memory.c:6318 handle_mm_fault+0x40a/0x8e0 mm/memory.c:6487 do_user_addr_fault+0xa7c/0x1380 arch/x86/mm/fault.c:1336 handle_page_fault arch/x86/mm/fault.c:1476 [inline] exc_page_fault+0x82/0x100 arch/x86/mm/fault.c:1532 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 RIP: 0033:0x7f03534550b3 RSP: 002b:00007ffe1e9da700 EFLAGS: 00010246 RAX: 0000200000000180 RBX: 0000000000000008 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00005555616f73c8 RBP: 00007ffe1e9da808 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 00007f03537b5fac R13: 00007f03537b5fa0 R14: fffffffffffffffe R15: 00007ffe1e9da850 Showing all locks held in the system: 1 lock held by khungtaskd/31: #0: ffffffff8dd3d2e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8dd3d2e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #0: ffffffff8dd3d2e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 4 locks held by kworker/u8:5/1044: #0: ffff88801ce8c948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3238 [inline] #0: ffff88801ce8c948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3346 #1: ffffc90003d6fba0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3239 [inline] #1: ffffc90003d6fba0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3346 #2: ffff8880294bc0e0 (&type->s_umount_key#53){.+.+}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:562 #3: ffff888028a20e50 (&sdp->sd_log_flush_lock){++++}-{4:4}, at: gfs2_log_flush+0x103/0x24c0 fs/gfs2/log.c:1045 2 locks held by getty/5606: #0: ffff8880340000a0 (&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 4 locks held by syz.0.17/6474: #0: ffff8880769eb088 (vm_lock){++++}-{0:0}, at: lock_vma_under_rcu+0x1a3/0x450 mm/mmap_lock.c:238 #1: ffff8880294bc518 (sb_pagefaults#2){.+.+}-{0:0}, at: do_page_mkwrite+0x14d/0x310 mm/memory.c:3488 #2: ffff8880294bc610 (sb_internal#2){.+.+}-{0:0}, at: gfs2_trans_begin+0x6f/0xe0 fs/gfs2/trans.c:118 #3: ffff888028a20e50 (&sdp->sd_log_flush_lock){++++}-{4:4}, at: gfs2_log_flush+0x103/0x24c0 fs/gfs2/log.c:1045 1 lock held by gfs2_logd/syz:s/6478: #0: ffff888028a20e50 (&sdp->sd_log_flush_lock){++++}-{4:4}, at: gfs2_log_flush+0x103/0x24c0 fs/gfs2/log.c:1045 1 lock held by udevd/7232: 6 locks held by syz.1.210/7282: ============================================= 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_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+0xf60/0xfa0 kernel/hung_task.c:495 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 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: 7282 Comm: syz.1.210 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 RIP: 0010:io_serial_in+0x77/0xc0 drivers/tty/serial/8250/8250_port.c:400 Code: e8 be 81 ae fc 44 89 f9 d3 e3 49 83 c6 40 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 ff 26 14 fd 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f c3 cc cc cc cc cc 44 89 f9 80 e1 07 RSP: 0018:ffffc900053ef278 EFLAGS: 00000006 RAX: 1ffffffff3317405 RBX: 00000000000003f9 RCX: 0000000000000000 RDX: 00000000000003f9 RSI: 0000000000000000 RDI: 0000000000000020 RBP: ffffc900053ef450 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: ffffffff85112030 R12: dffffc0000000000 R13: dffffc0000000000 R14: ffffffff998ba2e0 R15: 0000000000000000 FS: 00007f49985596c0(0000) GS:ffff88812616c000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f32979aa000 CR3: 0000000074f22000 CR4: 00000000003526f0 Call Trace: serial_port_in include/linux/serial_core.h:806 [inline] serial8250_console_write+0x584/0x1ba0 drivers/tty/serial/8250/8250_port.c:3306 console_emit_next_record kernel/printk/printk.c:3111 [inline] console_flush_all+0x6f3/0xb10 kernel/printk/printk.c:3199 __console_flush_and_unlock kernel/printk/printk.c:3258 [inline] console_unlock+0xbb/0x190 kernel/printk/printk.c:3298 vprintk_emit+0x4c5/0x590 kernel/printk/printk.c:2423 _printk+0xcf/0x120 kernel/printk/printk.c:2448 gfs2_sys_fs_add+0x39c/0x450 fs/gfs2/sys.c:764 gfs2_fill_super+0x13c0/0x20d0 fs/gfs2/ops_fstype.c:1208 get_tree_bdev_flags+0x40e/0x4d0 fs/super.c:1691 gfs2_get_tree+0x51/0x1e0 fs/gfs2/ops_fstype.c:1337 vfs_get_tree+0x92/0x2b0 fs/super.c:1751 fc_mount fs/namespace.c:1208 [inline] do_new_mount_fc fs/namespace.c:3651 [inline] do_new_mount+0x302/0x9e0 fs/namespace.c:3725 do_mount fs/namespace.c:4048 [inline] __do_sys_mount fs/namespace.c:4236 [inline] __se_sys_mount+0x313/0x410 fs/namespace.c:4213 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f499779038a Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 1a 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f4998558e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007f4998558ef0 RCX: 00007f499779038a RDX: 000020000001f680 RSI: 0000200000000040 RDI: 00007f4998558eb0 RBP: 000020000001f680 R08: 00007f4998558ef0 R09: 0000000000000094 R10: 0000000000000094 R11: 0000000000000246 R12: 0000200000000040 R13: 00007f4998558eb0 R14: 000000000001f790 R15: 00002000000001c0