INFO: task syz.1.750:17100 blocked for more than 143 seconds. Not tainted 6.16.0-rc7-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.1.750 state:D stack:28552 pid:17100 tgid:17072 ppid:15127 task_flags:0x400040 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5397 [inline] __schedule+0x16aa/0x4c90 kernel/sched/core.c:6786 __schedule_loop kernel/sched/core.c:6864 [inline] schedule+0x165/0x360 kernel/sched/core.c:6879 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6936 rwsem_down_write_slowpath+0xbec/0x1030 kernel/locking/rwsem.c:1176 __down_write_common kernel/locking/rwsem.c:1304 [inline] __down_write kernel/locking/rwsem.c:1313 [inline] down_write+0x1ab/0x1f0 kernel/locking/rwsem.c:1578 inode_lock include/linux/fs.h:869 [inline] generic_file_write_iter+0xe3/0x540 mm/filemap.c:4252 do_iter_readv_writev+0x56b/0x7f0 fs/read_write.c:-1 vfs_writev+0x31a/0x960 fs/read_write.c:1057 do_writev+0x14d/0x2d0 fs/read_write.c:1103 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fa3ae58e9a9 RSP: 002b:00007fa3af3a0038 EFLAGS: 00000246 ORIG_RAX: 0000000000000014 RAX: ffffffffffffffda RBX: 00007fa3ae7b6080 RCX: 00007fa3ae58e9a9 RDX: 0000000000000001 RSI: 00002000000001c0 RDI: 0000000000000004 RBP: 00007fa3ae610d69 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000001 R14: 00007fa3ae7b6080 R15: 00007fffd1786328 Showing all locks held in the system: 3 locks held by kworker/u8:0/12: 1 lock held by khungtaskd/31: #0: ffffffff8e13f0e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] ffffffff8e13f0e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] ffffffff8e13f0e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6770 2 locks held by getty/5597: #0: ffff8880310540a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000333b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222 2 locks held by syz.1.750/17074: 3 locks held by syz.1.750/17100: #0: ffff888029f07b38 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x247/0x320 fs/file.c:1217 #1: ffff88805bb40428 (sb_writers#37){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:3096 [inline] #1: ffff88805bb40428 (sb_writers#37){.+.+}-{0:0}, at: vfs_writev+0x288/0x960 fs/read_write.c:1055 #2: ffff88805be0c7a0 (&sb->s_type->i_mutex_key#42){++++}-{4:4}, at: inode_lock include/linux/fs.h:869 [inline] #2: ffff88805be0c7a0 (&sb->s_type->i_mutex_key#42){++++}-{4:4}, at: generic_file_write_iter+0xe3/0x540 mm/filemap.c:4252 1 lock held by syz-executor/17444: #0: ffffffff8e144bf8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:336 [inline] #0: ffffffff8e144bf8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b9/0x730 kernel/rcu/tree_exp.h:998 1 lock held by syz.2.1043/21304: 1 lock held by syz.9.1044/21330: 4 locks held by dhcpcd-run-hook/21361: ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.16.0-rc7-syzkaller #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:307 [inline] watchdog+0xfee/0x1030 kernel/hung_task.c:470 kthread+0x711/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 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: 17074 Comm: syz.1.750 Not tainted 6.16.0-rc7-syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:__sanitizer_cov_trace_pc+0x43/0x70 kernel/kcov.c:222 Code: e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 3c 16 00 00 00 74 2c 8b 91 18 16 00 00 83 fa 02 75 21 48 8b 91 20 16 00 00 <48> 8b 32 48 8d 7e 01 8b 89 1c 16 00 00 48 39 cf 73 08 48 89 3a 48 RSP: 0018:ffffc9001bc8e988 EFLAGS: 00000246 RAX: ffffffff8b62a709 RBX: 0000000000000025 RCX: ffff888027b6da00 RDX: ffffc90013f94000 RSI: 0000000000000025 RDI: 0000000000000000 RBP: ffffffff8b8b8920 R08: ffff888027b6da00 R09: 0000000000000002 R10: 0000000000000025 R11: 0000000000000002 R12: ffffffff8b8b8921 R13: ffffc9001bc8ea38 R14: 0000000000000000 R15: ffffffff8b8b8920 FS: 00007fa3af3c16c0(0000) GS:ffff888125c57000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f56f0382ab8 CR3: 0000000031262000 CR4: 00000000003526f0 Call Trace: format_decode+0xd9/0xe30 lib/vsprintf.c:2626 vsnprintf+0x102/0xf00 lib/vsprintf.c:2817 sprintf+0xd9/0x120 lib/vsprintf.c:3037 print_time kernel/printk/printk.c:1381 [inline] info_print_prefix+0x155/0x310 kernel/printk/printk.c:1407 record_print_text+0x154/0x430 kernel/printk/printk.c:1456 printk_get_next_message+0x26d/0x7b0 kernel/printk/printk.c:3024 console_emit_next_record kernel/printk/printk.c:3092 [inline] console_flush_all+0x4ca/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 _fat_msg+0x117/0x170 fs/fat/misc.c:62 __fat_fs_error+0x23d/0x2c0 fs/fat/misc.c:31 fat_chain_add+0x6a3/0x810 fs/fat/misc.c:161 fat_add_cluster+0xad/0x120 fs/fat/inode.c:112 fat_fallocate+0x1bd/0x2f0 fs/fat/file.c:292 vfs_fallocate+0x6a0/0x830 fs/open.c:341 ioctl_preallocate fs/ioctl.c:290 [inline] file_ioctl+0x611/0x780 fs/ioctl.c:-1 do_vfs_ioctl+0xe80/0x1990 fs/ioctl.c:886 __do_sys_ioctl fs/ioctl.c:905 [inline] __se_sys_ioctl+0x82/0x170 fs/ioctl.c:893 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fa3ae58e9a9 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:00007fa3af3c1038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fa3ae7b5fa0 RCX: 00007fa3ae58e9a9 RDX: 00002000000000c0 RSI: 0000000040305828 RDI: 0000000000000004 RBP: 00007fa3ae610d69 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fa3ae7b5fa0 R15: 00007fffd1786328