INFO: task syz-executor:14926 blocked for more than 143 seconds. Tainted: G L syzkaller #0 Blocked by coredump. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:21224 pid:14926 tgid:14926 ppid:1 task_flags:0x40014c flags:0x00080001 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x14bc/0x5000 kernel/sched/core.c:6863 __schedule_loop kernel/sched/core.c:6945 [inline] schedule+0x165/0x360 kernel/sched/core.c:6960 wb_wait_for_completion+0x360/0x680 fs/fs-writeback.c:226 sync_inodes_sb+0x1c9/0xb40 fs/fs-writeback.c:2894 sync_filesystem+0x17a/0x230 fs/sync.c:64 generic_shutdown_super+0x6f/0x2c0 fs/super.c:622 kill_block_super+0x44/0x90 fs/super.c:1722 ext4_kill_sb+0x68/0xb0 fs/ext4/super.c:7444 deactivate_locked_super+0xbc/0x130 fs/super.c:474 cleanup_mnt+0x425/0x4c0 fs/namespace.c:1318 task_work_run+0x1d4/0x260 kernel/task_work.c:233 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0x6c5/0x2310 kernel/exit.c:971 do_group_exit+0x21c/0x2d0 kernel/exit.c:1112 __do_sys_exit_group kernel/exit.c:1123 [inline] __se_sys_exit_group kernel/exit.c:1121 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1121 x64_sys_call+0x2210/0x2210 arch/x86/include/generated/asm/syscalls_64.h:232 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f9d0638f749 RSP: 002b:00007fff0140ead8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 00007f9d06413def RCX: 00007f9d0638f749 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000001 RBP: 0000000000000010 R08: 00007fff0140c876 R09: 00007fff0140fd90 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fff0140fd90 R13: 00007f9d06413d7d R14: 0000555573c5f4a8 R15: 00007fff01410e60 Showing all locks held in the system: 3 locks held by kworker/u8:0/12: 1 lock held by khungtaskd/31: #0: ffffffff8df419e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8df419e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #0: ffffffff8df419e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 6 locks held by kworker/u8:2/36: #0: ffff88801b2df148 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x841/0x15a0 kernel/workqueue.c:3236 #1: ffffc90000ac7b80 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x868/0x15a0 kernel/workqueue.c:3237 #2: ffffffff8f302df0 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf7/0x7a0 net/core/net_namespace.c:670 #3: ffff8880560dc0e8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:895 [inline] #3: ffff8880560dc0e8 (&dev->mutex){....}-{4:4}, at: devl_dev_lock net/devlink/devl_internal.h:108 [inline] #3: ffff8880560dc0e8 (&dev->mutex){....}-{4:4}, at: devlink_pernet_pre_exit+0x10a/0x3d0 net/devlink/core.c:506 #4: ffff8880206e3250 (&devlink->lock_key#17){+.+.}-{4:4}, at: devl_lock net/devlink/core.c:276 [inline] #4: ffff8880206e3250 (&devlink->lock_key#17){+.+.}-{4:4}, at: devl_dev_lock net/devlink/devl_internal.h:109 [inline] #4: ffff8880206e3250 (&devlink->lock_key#17){+.+.}-{4:4}, at: devlink_pernet_pre_exit+0x11c/0x3d0 net/devlink/core.c:506 #5: ffffffff8f310408 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #5: ffffffff8f310408 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_dev_lock+0x257/0x2f0 net/core/dev.c:2144 5 locks held by kworker/u8:5/73: 3 locks held by kworker/1:2/893: #0: ffff88813fe55948 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x841/0x15a0 kernel/workqueue.c:3236 #1: ffffc90003657b80 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_one_work+0x868/0x15a0 kernel/workqueue.c:3237 #2: ffff888073ae8240 (&data->fib_lock){+.+.}-{4:4}, at: nsim_fib_event_work+0x1f7/0x3b0 drivers/net/netdevsim/fib.c:1490 2 locks held by getty/5589: #0: ffff8880308bf0a0 (&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+0x449/0x1460 drivers/tty/n_tty.c:2211 3 locks held by kworker/u8:15/6030: #0: ffff888030805148 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x841/0x15a0 kernel/workqueue.c:3236 #1: ffffc90004d07b80 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x868/0x15a0 kernel/workqueue.c:3237 #2: ffffffff8f310408 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #2: ffffffff8f310408 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x112/0x14b0 net/ipv6/addrconf.c:4194 3 locks held by kworker/1:2H/6293: #0: ffff8880b873a918 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:639 #1: ffff8880b8724588 (psi_seq){-.-.}-{0:0}, at: psi_task_switch+0x53/0x880 kernel/sched/psi.c:933 #2: ffffffff8df46dd8 (rcu_node_0){-.-.}-{2:2}, at: rcu_preempt_deferred_qs_irqrestore+0x2c2/0xce0 kernel/rcu/tree_plugin.h:533 3 locks held by kworker/u8:4/11921: #0: ffff88813fe69948 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_one_work+0x841/0x15a0 kernel/workqueue.c:3236 #1: ffffc90018df7b80 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x868/0x15a0 kernel/workqueue.c:3237 #2: ffffffff8f310408 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:303 2 locks held by syz-executor/14926: #0: ffff88807c3ce0e0 (&type->s_umount_key#32){++++}-{4:4}, at: __super_lock fs/super.c:57 [inline] #0: ffff88807c3ce0e0 (&type->s_umount_key#32){++++}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline] #0: ffff88807c3ce0e0 (&type->s_umount_key#32){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:506 #1: ffff888141f12820 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:397 [inline] #1: ffff888141f12820 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: sync_inodes_sb+0x1ad/0xb40 fs/fs-writeback.c:2892 2 locks held by syz-executor/18712: #0: ffff888064be60e0 (&type->s_umount_key#32){++++}-{4:4}, at: __super_lock fs/super.c:57 [inline] #0: ffff888064be60e0 (&type->s_umount_key#32){++++}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline] #0: ffff888064be60e0 (&type->s_umount_key#32){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:506 #1: ffff8880254c8820 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:397 [inline] #1: ffff8880254c8820 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: sync_inodes_sb+0x1ad/0xb40 fs/fs-writeback.c:2892 1 lock held by syz-executor/19270: #0: ffffffff8f310408 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8f310408 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x3b0/0x18b0 net/ipv4/devinet.c:978 3 locks held by syz-executor/19411: #0: ffffffff8f377ff0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218 #1: ffffffff8f377e08 (genl_mutex){+.+.}-{4:4}, at: genl_lock net/netlink/genetlink.c:35 [inline] #1: ffffffff8f377e08 (genl_mutex){+.+.}-{4:4}, at: genl_op_lock net/netlink/genetlink.c:60 [inline] #1: ffffffff8f377e08 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10d/0x790 net/netlink/genetlink.c:1209 #2: ffffffff8f310408 (rtnl_mutex){+.+.}-{4:4}, at: wg_set_device_doit+0x15b/0x1fc0 drivers/net/wireguard/netlink.c:484 2 locks held by syz-executor/19456: #0: ffffffff8ea65f08 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8ea65f08 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #0: ffffffff8ea65f08 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250 net/core/rtnetlink.c:570 #1: ffffffff8f310408 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #1: ffffffff8f310408 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #1: ffffffff8f310408 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8ec/0x1c90 net/core/rtnetlink.c:4071 2 locks held by syz-executor/19493: #0: ffffffff8f823e30 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8f823e30 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #0: ffffffff8f823e30 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250 net/core/rtnetlink.c:570 #1: ffffffff8f310408 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #1: ffffffff8f310408 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #1: ffffffff8f310408 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8ec/0x1c90 net/core/rtnetlink.c:4071 2 locks held by syz.6.3211/19517: #0: ffffffff8f310408 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline] #0: ffffffff8f310408 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0 drivers/net/tun.c:3436 #1: ffffffff8df47538 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:311 [inline] #1: ffffffff8df47538 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2f6/0x730 kernel/rcu/tree_exp.h:956 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 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] __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+0xf95/0xfe0 kernel/hung_task.c:515 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 73 Comm: kworker/u8:5 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Workqueue: writeback wb_workfn (flush-7:5) RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:209 [inline] RIP: 0010:unwind_next_frame+0x1e5/0x2390 arch/x86/kernel/unwind_orc.c:494 Code: a2 01 00 00 49 81 fc 00 00 00 81 0f 92 c0 49 81 fc 70 2b 5f 8b 0f 93 c1 08 c1 0f 85 e8 00 00 00 48 c7 c0 00 00 00 81 4d 89 e7 <49> 29 c7 49 c1 ef 08 8b 15 5e e2 26 0c 8d 42 ff 44 39 f8 0f 86 65 RSP: 0018:ffffc9000218dcb8 EFLAGS: 00000246 RAX: ffffffff81000000 RBX: 0000000000000001 RCX: 6c937832a00cc600 RDX: ffffffff8b6892e0 RSI: ffffffff8bc07b40 RDI: ffffffff8bc07b00 RBP: dffffc0000000000 R08: ffffffff81743f85 R09: ffffffff8df419e0 R10: ffffc9000218ddd8 R11: ffffffff81ada2b0 R12: ffffffff8248a622 R13: ffffc9000218ddd8 R14: ffffc9000218dd88 R15: ffffffff8248a622 FS: 0000000000000000(0000) GS:ffff888125f37000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f2e30517d60 CR3: 000000000dd3a000 CR4: 00000000003526f0 DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000083 DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366 kasan_slab_alloc include/linux/kasan.h:252 [inline] slab_post_alloc_hook mm/slub.c:4953 [inline] slab_alloc_node mm/slub.c:5263 [inline] kmem_cache_alloc_noprof+0x37d/0x710 mm/slub.c:5270 mempool_alloc_noprof+0x1c9/0x2f0 mm/mempool.c:567 bio_alloc_bioset+0x28d/0x12d0 block/bio.c:557 bio_alloc include/linux/bio.h:374 [inline] submit_bh_wbc+0x22e/0x520 fs/buffer.c:2804 ext4_commit_super+0x2d2/0x430 fs/ext4/super.c:6275 ext4_handle_error+0x65e/0x950 fs/ext4/super.c:718 __ext4_std_error+0x272/0x500 fs/ext4/super.c:970 ext4_reserve_inode_write+0x216/0x360 fs/ext4/inode.c:6298 __ext4_mark_inode_dirty+0x14b/0x6e0 fs/ext4/inode.c:6465 ext4_split_extent_at+0x67a/0xe30 fs/ext4/extents.c:3239 ext4_split_extent+0x278/0x730 fs/ext4/extents.c:3426 ext4_split_convert_extents fs/ext4/extents.c:3767 [inline] ext4_ext_handle_unwritten_extents fs/ext4/extents.c:3941 [inline] ext4_ext_map_blocks+0x26b6/0x6c80 fs/ext4/extents.c:4305 ext4_map_create_blocks fs/ext4/inode.c:613 [inline] ext4_map_blocks+0x82c/0x16f0 fs/ext4/inode.c:816 mpage_map_one_extent fs/ext4/inode.c:2380 [inline] mpage_map_and_submit_extent fs/ext4/inode.c:2474 [inline] ext4_do_writepages+0x222f/0x4500 fs/ext4/inode.c:2932 ext4_writepages+0x203/0x350 fs/ext4/inode.c:3026 do_writepages+0x32e/0x550 mm/page-writeback.c:2598 __writeback_single_inode+0x133/0x1240 fs/fs-writeback.c:1737 writeback_sb_inodes+0x93a/0x1870 fs/fs-writeback.c:2030 wb_writeback+0x42b/0xaa0 fs/fs-writeback.c:2216 wb_do_writeback fs/fs-writeback.c:2363 [inline] wb_workfn+0x3f9/0xed0 fs/fs-writeback.c:2403 process_one_work+0x93a/0x15a0 kernel/workqueue.c:3261 process_scheduled_works kernel/workqueue.c:3344 [inline] worker_thread+0x9b0/0xee0 kernel/workqueue.c:3425 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246