INFO: task syz.5.193:7287 blocked for more than 143 seconds. Not tainted 6.15.0-rc6-syzkaller-00346-g5723cc3450bc #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.5.193 state:D stack:28752 pid:7287 tgid:7277 ppid:6121 task_flags:0x400040 flags:0x00000004 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x168f/0x4c70 kernel/sched/core.c:6767 __schedule_loop kernel/sched/core.c:6845 [inline] schedule+0x165/0x360 kernel/sched/core.c:6860 percpu_rwsem_wait+0x2ab/0x300 kernel/locking/percpu-rwsem.c:162 __percpu_down_read+0xe3/0x120 kernel/locking/percpu-rwsem.c:177 percpu_down_read include/linux/percpu-rwsem.h:66 [inline] __sb_start_write include/linux/fs.h:1783 [inline] sb_start_write+0x185/0x1c0 include/linux/fs.h:1919 mnt_want_write+0x41/0x90 fs/namespace.c:556 filename_create+0x13a/0x470 fs/namei.c:4125 do_mkdirat+0xa0/0x590 fs/namei.c:4384 __do_sys_mkdirat fs/namei.c:4409 [inline] __se_sys_mkdirat fs/namei.c:4407 [inline] __x64_sys_mkdirat+0x87/0xa0 fs/namei.c:4407 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f2c8218d1d7 RSP: 002b:00007f2c8307ce68 EFLAGS: 00000246 ORIG_RAX: 0000000000000102 RAX: ffffffffffffffda RBX: 00007f2c8307cef0 RCX: 00007f2c8218d1d7 RDX: 00000000000001ff RSI: 0000200000000100 RDI: 00000000ffffff9c RBP: 0000000000000000 R08: 0000200000000080 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000200000000100 R13: 00007f2c8307ceb0 R14: 0000000000000000 R15: 0000000000000000 Showing all locks held in the system: 3 locks held by kworker/u8:1/13: 1 lock held by khungtaskd/31: #0: ffffffff8df3dee0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8df3dee0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8df3dee0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6764 3 locks held by kworker/u8:2/36: 2 locks held by kworker/u8:6/1162: 2 locks held by getty/5583: #0: ffff8880303ff0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc900036d32f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222 1 lock held by syz-executor/5818: 1 lock held by udevd/5830: 1 lock held by udevd/5987: 1 lock held by syz.5.193/7287: #0: ffff8880787d4420 (sb_writers#16){++++}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:556 1 lock held by syz-executor/8068: #0: ffffffff8df439b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:336 [inline] #0: ffffffff8df439b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b7/0x730 kernel/rcu/tree_exp.h:998 1 lock held by syz.0.532/9748: 1 lock held by dhcpcd-run-hook/9759: ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.15.0-rc6-syzkaller-00346-g5723cc3450bc #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 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:158 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:274 [inline] watchdog+0xfee/0x1030 kernel/hung_task.c:437 kthread+0x711/0x8a0 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153 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: 9731 Comm: syz.9.531 Not tainted 6.15.0-rc6-syzkaller-00346-g5723cc3450bc #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:io_serial_in+0x77/0xc0 drivers/tty/serial/8250/8250_port.c:409 Code: e8 ee e7 88 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 8f bc e8 fc 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:ffffc9000a956eb8 EFLAGS: 00000006 RAX: 1ffffffff3364305 RBX: 00000000000003f9 RCX: 0000000000000000 RDX: 00000000000003f9 RSI: 000000000000bc1b RDI: 000000000000bc1c RBP: ffffc9000a957090 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: ffffffff853708a0 R12: dffffc0000000000 R13: dffffc0000000000 R14: ffffffff99b21a00 R15: 0000000000000000 FS: 00007f7118cc26c0(0000) GS:ffff8881260f6000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fbaca015000 CR3: 00000000566a2000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: serial_port_in include/linux/serial_core.h:791 [inline] serial8250_console_write+0x581/0x1ba0 drivers/tty/serial/8250/8250_port.c:3420 console_emit_next_record kernel/printk/printk.c:3138 [inline] console_flush_all+0x728/0xc40 kernel/printk/printk.c:3226 __console_flush_and_unlock kernel/printk/printk.c:3285 [inline] console_unlock+0xc4/0x270 kernel/printk/printk.c:3325 vprintk_emit+0x5b7/0x7a0 kernel/printk/printk.c:2450 _printk+0xcf/0x120 kernel/printk/printk.c:2475 f2fs_printk+0x3d8/0x470 fs/f2fs/super.c:-1 f2fs_check_nid_range fs/f2fs/node.c:37 [inline] __get_node_folio+0x8cc/0xdb0 fs/f2fs/node.c:1489 f2fs_get_node_page fs/f2fs/node.c:1539 [inline] f2fs_get_dnode_of_data+0x7c7/0x1c30 fs/f2fs/node.c:837 f2fs_get_read_data_folio+0x1a3/0x690 fs/f2fs/data.c:1229 f2fs_find_data_folio+0x195/0x3c0 fs/f2fs/data.c:1296 f2fs_find_data_page fs/f2fs/f2fs.h:3984 [inline] find_in_level fs/f2fs/dir.c:287 [inline] __f2fs_find_entry+0x630/0xc60 fs/f2fs/dir.c:362 f2fs_lookup+0x25e/0x930 fs/f2fs/namei.c:484 lookup_one_qstr_excl_raw+0x118/0x280 fs/namei.c:1689 lookup_one_qstr_excl fs/namei.c:1711 [inline] filename_create+0x225/0x470 fs/namei.c:4133 do_mknodat+0x184/0x4d0 fs/namei.c:4265 __do_sys_mknod fs/namei.c:4311 [inline] __se_sys_mknod fs/namei.c:4309 [inline] __x64_sys_mknod+0x8c/0xa0 fs/namei.c:4309 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f7117d8e969 Code: ff ff c3 66 2e 0f 1f 84 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 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f7118cc2038 EFLAGS: 00000246 ORIG_RAX: 0000000000000085 RAX: ffffffffffffffda RBX: 00007f7117fb5fa0 RCX: 00007f7117d8e969 RDX: 0000000000000712 RSI: 000000000000c000 RDI: 0000200000000380 RBP: 00007f7117e10ab1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f7117fb5fa0 R15: 00007ffde5968c08