INFO: task syz.8.551:13730 blocked for more than 143 seconds. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.8.551 state:D stack:29024 pid:13730 tgid:13624 ppid:10377 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5298 [inline] __schedule+0x1553/0x5240 kernel/sched/core.c:6911 __schedule_loop kernel/sched/core.c:6993 [inline] rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7289 rt_mutex_slowlock_block kernel/locking/rtmutex.c:1647 [inline] __rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline] __rt_mutex_slowlock_locked+0x1f8f/0x25c0 kernel/locking/rtmutex.c:1760 rt_mutex_slowlock+0xbd/0x170 kernel/locking/rtmutex.c:1800 __rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline] rwbase_write_lock+0x14d/0x730 kernel/locking/rwbase_rt.c:244 inode_lock_nested include/linux/fs.h:1073 [inline] lock_rename fs/namei.c:3762 [inline] __start_renaming+0x148/0x410 fs/namei.c:3858 filename_renameat2+0x38c/0x9c0 fs/namei.c:6125 __do_sys_rename fs/namei.c:6194 [inline] __se_sys_rename+0x55/0x2c0 fs/namei.c:6190 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fa42eb9c819 RSP: 002b:00007fa42cdcd028 EFLAGS: 00000246 ORIG_RAX: 0000000000000052 RAX: ffffffffffffffda RBX: 00007fa42ee16090 RCX: 00007fa42eb9c819 RDX: 0000000000000000 RSI: 0000200000000080 RDI: 0000200000000000 RBP: 00007fa42ec32c91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fa42ee16128 R14: 00007fa42ee16090 R15: 00007fff29111248 INFO: task syz.8.551:13733 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.8.551 state:D stack:26688 pid:13733 tgid:13624 ppid:10377 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5298 [inline] __schedule+0x1553/0x5240 kernel/sched/core.c:6911 __schedule_loop kernel/sched/core.c:6993 [inline] rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7289 rt_mutex_slowlock_block kernel/locking/rtmutex.c:1647 [inline] __rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline] __rt_mutex_slowlock_locked+0x1f8f/0x25c0 kernel/locking/rtmutex.c:1760 rt_mutex_slowlock+0xbd/0x170 kernel/locking/rtmutex.c:1800 __rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline] rwbase_write_lock+0x14d/0x730 kernel/locking/rwbase_rt.c:244 inode_lock include/linux/fs.h:1028 [inline] open_last_lookups fs/namei.c:4586 [inline] path_openat+0xb5e/0x38a0 fs/namei.c:4833 do_file_open+0x23e/0x4a0 fs/namei.c:4865 do_sys_openat2+0x113/0x200 fs/open.c:1366 do_sys_open fs/open.c:1372 [inline] __do_sys_openat fs/open.c:1388 [inline] __se_sys_openat fs/open.c:1383 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1383 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fa42eb9c819 RSP: 002b:00007fa42cdac028 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007fa42ee16180 RCX: 00007fa42eb9c819 RDX: 00000000000c4042 RSI: 0000200000000300 RDI: ffffffffffffff9c RBP: 00007fa42ec32c91 R08: 0000000000000000 R09: 0000000000000000 R10: 00000000000001ff R11: 0000000000000246 R12: 0000000000000000 R13: 00007fa42ee16218 R14: 00007fa42ee16180 R15: 00007fff29111248 Showing all locks held in the system: 1 lock held by khungtaskd/37: #0: ffffffff8ddcb9c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline] #0: ffffffff8ddcb9c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline] #0: ffffffff8ddcb9c0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 4 locks held by kworker/u8:12/3471: #0: ffff88801aee5138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline] #0: ffff88801aee5138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0xa52/0x18c0 kernel/workqueue.c:3359 #1: ffffc9000e7bfc40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3252 [inline] #1: ffffc9000e7bfc40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa8d/0x18c0 kernel/workqueue.c:3359 #2: ffff88802bfc60d0 (&type->s_umount_key#53){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:565 #3: ffff88806155e368 (&jfs_ip->commit_mutex){+.+.}-{4:4}, at: jfs_commit_inode+0x1ca/0x530 fs/jfs/inode.c:108 3 locks held by dhcpcd/5459: 2 locks held by getty/5549: #0: ffff8880376e00a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc90003e8b2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x462/0x13c0 drivers/tty/n_tty.c:2211 4 locks held by syz.8.551/13625: 2 locks held by syz.8.551/13730: #0: ffff88802bfc6480 (sb_writers#19){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:493 #1: ffff88806155e738 (&type->i_mutex_dir_key#12/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1073 [inline] #1: ffff88806155e738 (&type->i_mutex_dir_key#12/1){+.+.}-{4:4}, at: lock_rename fs/namei.c:3762 [inline] #1: ffff88806155e738 (&type->i_mutex_dir_key#12/1){+.+.}-{4:4}, at: __start_renaming+0x148/0x410 fs/namei.c:3858 2 locks held by syz.8.551/13733: #0: ffff88802bfc6480 (sb_writers#19){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:493 #1: ffff88806155e738 (&type->i_mutex_dir_key#13){++++}-{4:4}, at: inode_lock include/linux/fs.h:1028 [inline] #1: ffff88806155e738 (&type->i_mutex_dir_key#13){++++}-{4:4}, at: open_last_lookups fs/namei.c:4586 [inline] #1: ffff88806155e738 (&type->i_mutex_dir_key#13){++++}-{4:4}, at: path_openat+0xb5e/0x38a0 fs/namei.c:4833 2 locks held by syz.7.767/17107: #0: ffff88802bfc60d0 (&type->s_umount_key#53){++++}-{4:4}, at: __super_lock fs/super.c:60 [inline] #0: ffff88802bfc60d0 (&type->s_umount_key#53){++++}-{4:4}, at: super_lock+0x2d6/0x3d0 fs/super.c:122 #1: ffff888025ce48c0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:398 [inline] #1: ffff888025ce48c0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: sync_inodes_sb+0x209/0xc30 fs/fs-writeback.c:2940 8 locks held by syz-executor/17454: 3 locks held by syz.5.821/17934: 2 locks held by syz.2.820/17939: 2 locks held by syz.3.822/17954: #0: ffff888025b5a498 (&lo->lo_mutex){+.+.}-{4:4}, at: loop_global_lock_killable drivers/block/loop.c:118 [inline] #0: ffff888025b5a498 (&lo->lo_mutex){+.+.}-{4:4}, at: loop_configure+0x37b/0xdf0 drivers/block/loop.c:1016 #1: ffff888019c4f238 (&root->kernfs_rwsem){++++}-{4:4}, at: kernfs_add_one+0x41/0x5c0 fs/kernfs/dir.c:796 2 locks held by dhcpcd/17955: 3 locks held by syz.6.824/17956: 7 locks held by dhcpcd/17959: ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:161 [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:346 [inline] watchdog+0xfd9/0x1030 kernel/hung_task.c:515 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x51e/0xb90 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: 17954 Comm: syz.3.822 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 RIP: 0010:__sanitizer_cov_trace_switch+0x5a/0x140 kernel/kcov.c:-1 Code: 75 36 e9 03 01 00 00 48 83 f9 03 0f 84 eb 00 00 00 48 83 f9 07 0f 85 ef 00 00 00 b9 07 00 00 00 48 85 c0 75 13 e9 e0 00 00 00 01 00 00 00 48 85 c0 0f 84 d2 00 00 00 55 41 57 41 56 41 55 41 RSP: 0018:ffffc90006bcede8 EFLAGS: 00000246 RAX: 0000000000000002 RBX: 0000000000000072 RCX: 0000000000000000 RDX: ffffc9001a1a0000 RSI: ffffffff8f51abb0 RDI: 0000000000000072 RBP: ffffffff8c77ed60 R08: ffff88802a12bd00 R09: 0000000000000002 R10: 0000000000000100 R11: 0000000000000025 R12: ffffffff8c77ed7d R13: ffffc90006bcee98 R14: 000000000000001d R15: ffffffff8c77ed60 FS: 00007f21f63966c0(0000) GS:ffff888126335000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000557ddba8ca78 CR3: 0000000033eb4000 CR4: 00000000003526f0 Call Trace: format_decode+0x84/0xe10 lib/vsprintf.c:2692 vsnprintf+0x102/0xee0 lib/vsprintf.c:2890 add_uevent_var+0x1ce/0x460 lib/kobject_uevent.c:679 kobject_uevent_env+0x5dc/0x9e0 lib/kobject_uevent.c:619 loop_configure+0xb2f/0xdf0 drivers/block/loop.c:1092 lo_ioctl+0x447/0x1fc0 drivers/block/loop.c:1534 blkdev_ioctl+0x5e6/0x750 block/ioctl.c:804 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl+0xff/0x170 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f21f813c4ab Code: 00 48 89 44 24 18 31 c0 48 8d 44 24 60 c7 04 24 10 00 00 00 48 89 44 24 08 48 8d 44 24 20 48 89 44 24 10 b8 10 00 00 00 0f 05 <89> c2 3d 00 f0 ff ff 77 1c 48 8b 44 24 18 64 48 2b 04 25 28 00 00 RSP: 002b:00007f21f6395db0 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007f21f813c4ab RDX: 0000000000000003 RSI: 0000000000004c00 RDI: 0000000000000004 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003 R13: 00007f21f6395ee0 R14: 00007f21f6395ea0 R15: 00007f21edf76000