INFO: task syz-executor:5771 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:20968 pid:5771 ppid:1 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x1553/0x45a0 kernel/sched/core.c:6700 schedule+0xbd/0x170 kernel/sched/core.c:6774 wb_wait_for_completion+0x173/0x2a0 fs/fs-writeback.c:192 sync_inodes_sb+0x1c9/0xa10 fs/fs-writeback.c:2772 sync_filesystem+0x171/0x220 fs/sync.c:64 generic_shutdown_super+0x6f/0x2b0 fs/super.c:666 kill_block_super+0x44/0x90 fs/super.c:1660 deactivate_locked_super+0x97/0x100 fs/super.c:481 cleanup_mnt+0x43b/0x4d0 fs/namespace.c:1259 task_work_run+0x1d4/0x260 kernel/task_work.c:245 exit_task_work include/linux/task_work.h:43 [inline] do_exit+0x95a/0x2460 kernel/exit.c:883 do_group_exit+0x21b/0x2d0 kernel/exit.c:1024 __do_sys_exit_group kernel/exit.c:1035 [inline] __se_sys_exit_group kernel/exit.c:1033 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1033 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fa73919aeb9 RSP: 002b:00007fffd5bc9918 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 00007fa7392047ae RCX: 00007fa73919aeb9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000001 RBP: 000000000000000c R08: 0000000000000000 R09: 00007fa73920471f R10: 0000000000000000 R11: 0000000000000246 R12: 00007fffd5bcabd0 R13: 00007fa73920471f R14: 000055556fc6a4e8 R15: 00007fffd5bcbca0 Showing all locks held in the system: 1 lock held by pool_workqueue_/3: #0: ffffffff8d1379b8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:324 [inline] #0: ffffffff8d1379b8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x3da/0x880 kernel/rcu/tree_exp.h:1004 1 lock held by khungtaskd/29: #0: ffffffff8d131fe0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline] #0: ffffffff8d131fe0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline] #0: ffffffff8d131fe0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x290 kernel/locking/lockdep.c:6633 2 locks held by kworker/u4:10/3477: 2 locks held by getty/5529: #0: ffff88802cdb40a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000326e2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x433/0x1390 drivers/tty/n_tty.c:2217 3 locks held by udevd/5762: 2 locks held by syz-executor/5771: #0: ffff88805a9a60e0 (&type->s_umount_key#60){+.+.}-{3:3}, at: __super_lock fs/super.c:56 [inline] #0: ffff88805a9a60e0 (&type->s_umount_key#60){+.+.}-{3:3}, at: __super_lock_excl fs/super.c:71 [inline] #0: ffff88805a9a60e0 (&type->s_umount_key#60){+.+.}-{3:3}, at: deactivate_super+0xa4/0xe0 fs/super.c:513 #1: ffff8881413aa7d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:364 [inline] #1: ffff8881413aa7d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0x1ad/0xa10 fs/fs-writeback.c:2770 1 lock held by syz-executor/5783: #0: ffffffff8d1379b8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:324 [inline] #0: ffffffff8d1379b8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x3da/0x880 kernel/rcu/tree_exp.h:1004 2 locks held by kworker/1:5/5836: #0: ffff888017c72538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline] #0: ffff888017c72538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_scheduled_works+0x96f/0x15d0 kernel/workqueue.c:2711 #1: ffffc90004a7fd00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline] #1: ffffc90004a7fd00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_scheduled_works+0x96f/0x15d0 kernel/workqueue.c:2711 3 locks held by kworker/0:5/5858: #0: ffff888017c70938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline] #0: ffff888017c70938 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x96f/0x15d0 kernel/workqueue.c:2711 #1: ffff8880b8e289c0 (psi_seq){-.-.}-{0:0}, at: psi_sched_switch kernel/sched/stats.h:189 [inline] #1: ffff8880b8e289c0 (psi_seq){-.-.}-{0:0}, at: __schedule+0x2176/0x45a0 kernel/sched/core.c:6695 #2: ffff8880252a4240 (&data->fib_lock){+.+.}-{3:3}, at: nsim_fib_event_work+0x286/0x31b0 drivers/net/netdevsim/fib.c:1491 2 locks held by syz.4.619/8527: #0: ffff88805d11fc70 (&fc->uapi_mutex){+.+.}-{3:3}, at: __do_sys_fsconfig fs/fsopen.c:479 [inline] #0: ffff88805d11fc70 (&fc->uapi_mutex){+.+.}-{3:3}, at: __se_sys_fsconfig+0x6e1/0x850 fs/fsopen.c:355 #1: ffff8880192ba0e0 (&type->s_umount_key#32){++++}-{3:3}, at: vfs_cmd_reconfigure fs/fsopen.c:272 [inline] #1: ffff8880192ba0e0 (&type->s_umount_key#32){++++}-{3:3}, at: vfs_fsconfig_locked+0x164/0x320 fs/fsopen.c:302 1 lock held by dhcpcd/8536: #0: ffff88805e1c1a20 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:804 [inline] #0: ffff88805e1c1a20 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: __sock_release net/socket.c:658 [inline] #0: ffff88805e1c1a20 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: sock_close+0x9b/0x230 net/socket.c:1420 1 lock held by dhcpcd/8537: #0: ffff8880595e5620 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:804 [inline] #0: ffff8880595e5620 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: __sock_release net/socket.c:658 [inline] #0: ffff8880595e5620 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: sock_close+0x9b/0x230 net/socket.c:1420 1 lock held by dhcpcd/8538: #0: ffff8880595e6e20 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:804 [inline] #0: ffff8880595e6e20 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: __sock_release net/socket.c:658 [inline] #0: ffff8880595e6e20 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: sock_close+0x9b/0x230 net/socket.c:1420 1 lock held by dhcpcd/8539: #0: ffff88805e1c7420 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:804 [inline] #0: ffff88805e1c7420 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: __sock_release net/socket.c:658 [inline] #0: ffff88805e1c7420 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: sock_close+0x9b/0x230 net/socket.c:1420 1 lock held by dhcpcd/8542: #0: ffff8880257b2130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1780 [inline] #0: ffff8880257b2130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x32/0xcc0 net/packet/af_packet.c:3258 1 lock held by dhcpcd/8547: #0: ffff8880248a4130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1780 [inline] #0: ffff8880248a4130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x32/0xcc0 net/packet/af_packet.c:3258 2 locks held by dhcpcd-run-hook/8548: ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 29 Comm: khungtaskd Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106 nmi_cpu_backtrace+0x3a6/0x3e0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/0x2f0 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline] watchdog+0xf3d/0xf80 kernel/hung_task.c:379 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 8548 Comm: dhcpcd-run-hook Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:check_kcov_mode kernel/kcov.c:193 [inline] RIP: 0010:write_comp_data kernel/kcov.c:245 [inline] RIP: 0010:__sanitizer_cov_trace_switch+0xb9/0x120 kernel/kcov.c:350 Code: 44 8b 1d 52 9d 7c 7e 41 81 e3 00 01 ff 00 74 13 41 81 fb 00 01 00 00 75 d9 41 83 b8 1c 16 00 00 00 74 cf 45 8b 98 f8 15 00 00 <41> 83 fb 03 75 c2 4d 8b 98 00 16 00 00 45 8b b8 fc 15 00 00 49 c1 RSP: 0018:ffffc900033673f0 EFLAGS: 00000246 RAX: 0000000000000003 RBX: ffffffff8f1ad3ec RCX: 0000000000000003 RDX: ffffffff813b4cf9 RSI: ffffffff8cfa07e0 RDI: 0000000000000001 RBP: ffffc90003367538 R08: ffff88802b5f1e00 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffffc900033674e8 R13: dffffc0000000000 R14: 0000000000000001 R15: ffffffff8f1ad3f0 FS: 00007fe73bd85c80(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fe73c0a1feb CR3: 000000007b130000 CR4: 00000000003506e0 Call Trace: unwind_next_frame+0x16d9/0x2970 arch/x86/kernel/unwind_orc.c:641 arch_stack_walk+0x144/0x190 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xaa/0x100 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4e/0x70 mm/kasan/common.c:53 kasan_save_free_info+0x2e/0x50 mm/kasan/generic.c:522 ____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:237 kasan_slab_free include/linux/kasan.h:164 [inline] slab_free_hook mm/slub.c:1811 [inline] slab_free_freelist_hook+0x130/0x1a0 mm/slub.c:1837 slab_free mm/slub.c:3830 [inline] __kmem_cache_free+0xba/0x1e0 mm/slub.c:3843 tomoyo_realpath_from_path+0x59d/0x5d0 security/tomoyo/realpath.c:286 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_path_perm+0x282/0x560 security/tomoyo/file.c:822 security_inode_getattr+0xd3/0x120 security/security.c:2153 vfs_getattr fs/stat.c:173 [inline] vfs_statx+0x172/0x680 fs/stat.c:248 vfs_fstatat+0x12a/0x1b0 fs/stat.c:299 __do_sys_newfstatat fs/stat.c:463 [inline] __se_sys_newfstatat fs/stat.c:457 [inline] __x64_sys_newfstatat+0x149/0x1f0 fs/stat.c:457 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fe73bf3fb0a Code: 48 8b 15 f1 f2 0d 00 f7 d8 64 89 02 b8 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 41 89 ca b8 06 01 00 00 0f 05 <3d> 00 f0 ff ff 77 07 31 c0 c3 0f 1f 40 00 48 8b 15 b9 f2 0d 00 f7 RSP: 002b:00007fff1b471888 EFLAGS: 00000246 ORIG_RAX: 0000000000000106 RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 00007fe73bf3fb0a RDX: 00007fff1b471898 RSI: 000055e64f9d7fe0 RDI: 00000000ffffff9c RBP: 000055e64f9d1040 R08: 0000000000000001 R09: 3c00000040001201 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fe73c0c7322 R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000000