INFO: task syz-executor:7154 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:21552 pid:7154 ppid:1 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5245 [inline] __schedule+0x11d1/0x40e0 kernel/sched/core.c:6562 schedule+0xb9/0x180 kernel/sched/core.c:6638 wb_wait_for_completion+0x16f/0x290 fs/fs-writeback.c:191 sync_inodes_sb+0x1c5/0xa10 fs/fs-writeback.c:2756 sync_filesystem+0x16d/0x220 fs/sync.c:64 generic_shutdown_super+0x6b/0x340 fs/super.c:474 kill_block_super+0x7c/0xe0 fs/super.c:1470 deactivate_locked_super+0x93/0xf0 fs/super.c:332 cleanup_mnt+0x42c/0x4b0 fs/namespace.c:1191 task_work_run+0x1d0/0x260 kernel/task_work.c:203 exit_task_work include/linux/task_work.h:39 [inline] do_exit+0x982/0x2480 kernel/exit.c:880 do_group_exit+0x217/0x2d0 kernel/exit.c:1022 __do_sys_exit_group kernel/exit.c:1033 [inline] __se_sys_exit_group kernel/exit.c:1031 [inline] __x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1031 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f4b7679c819 RSP: 002b:00007ffcfd59ffb8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 00007f4b768320ba RCX: 00007f4b7679c819 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000001 RBP: 0000000000000010 R08: 0000000000000000 R09: 00007f4b76832048 R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffcfd5a1270 R13: 00007f4b76832048 R14: 00005555928424e8 R15: 00007ffcfd5a2340 Showing all locks held in the system: 1 lock held by rcu_tasks_kthre/12: #0: ffffffff8cb2df30 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517 1 lock held by rcu_tasks_trace/13: #0: ffffffff8cb2e750 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517 1 lock held by khungtaskd/28: #0: ffffffff8cb2d5a0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #0: ffffffff8cb2d5a0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #0: ffffffff8cb2d5a0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6513 3 locks held by kworker/u4:4/56: 5 locks held by kworker/0:1H/93: #0: ffff8880b8e3ab18 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:538 #1: ffff8880b8e27888 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x398/0x6d0 kernel/sched/psi.c:999 #2: ffffffff8cb2d5a0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #2: ffffffff8cb2d5a0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #2: ffffffff8cb2d5a0 (rcu_read_lock){....}-{1:2}, at: xa_find_after+0xab/0x430 lib/xarray.c:2085 #3: ffff8880249738d8 (&lo->lo_work_lock){..-.}-{2:2}, at: spin_lock_irq include/linux/spinlock.h:376 [inline] #3: ffff8880249738d8 (&lo->lo_work_lock){..-.}-{2:2}, at: loop_queue_work drivers/block/loop.c:834 [inline] #3: ffff8880249738d8 (&lo->lo_work_lock){..-.}-{2:2}, at: loop_queue_rq+0x224/0xac0 drivers/block/loop.c:1874 #4: ffffffff8cb2d5a0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #4: ffffffff8cb2d5a0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #4: ffffffff8cb2d5a0 (rcu_read_lock){....}-{1:2}, at: __queue_work+0xeb/0xfb0 kernel/workqueue.c:1443 3 locks held by kworker/1:2/129: #0: ffff88814cc79938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267 #1: ffffc90002e17d00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267 #2: ffffffff8dd47de8 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xca/0x14f0 net/ipv6/addrconf.c:4131 2 locks held by getty/4028: #0: ffff88814dc28098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244 #1: ffffc9000327b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x429/0x1390 drivers/tty/n_tty.c:2198 3 locks held by kworker/0:3/4271: #0: ffff88814cc79938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267 #1: ffffc90004037d00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267 #2: ffffffff8dd47de8 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xca/0x14f0 net/ipv6/addrconf.c:4131 3 locks held by kworker/0:6/4312: #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267 #1: ffffc90004637d00 (fqdir_free_work){+.+.}-{0:0} , at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267 #2: ffffffff8cb33140 (rcu_state.barrier_mutex){+.+.}-{3:3}, at: rcu_barrier+0x48/0x600 kernel/rcu/tree.c:4023 4 locks held by kworker/u4:9/4361: #0: ffff888019e5e938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267 #1: ffffc9000480fd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267 #2: ffff8880281f8c18 (&sbi->s_writepages_rwsem){.+.+}-{0:0}, at: ext4_writepages+0x20f/0x2f40 fs/ext4/inode.c:2717 #3: ffff8880716e8c90 (&ei->i_data_sem){++++}-{3:3}, at: ext4_map_blocks+0x910/0x1b70 fs/ext4/inode.c:674 6 locks held by kworker/u4:11/4398: #0: ffff888017616938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267 #1: ffffc900049efd00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267 #2: ffffffff8dd3af10 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x148/0xba0 net/core/net_namespace.c:594 #3: ffffffff8dd47de8 (rtnl_mutex){+.+.}-{3:3}, at: caif_exit_net+0x66/0x490 net/caif/caif_dev.c:527 #4: ffff88801ee6dd80 (&caifn->caifdevs.lock){+.+.}-{3:3}, at: caif_exit_net+0x79/0x490 net/caif/caif_dev.c:528 #5: ffffffff8cb33278 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:291 [inline] #5: ffffffff8cb33278 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x2ec/0x890 kernel/rcu/tree_exp.h:962 2 locks held by kworker/u4:18/4711: 2 locks held by syz-executor/6878: #0: ffff88801ea880e0 (&type->s_umount_key#31){++++}-{3:3}, at: deactivate_super+0xa0/0xd0 fs/super.c:362 #1: ffff8880249847d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:362 [inline] #1: ffff8880249847d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0x1a9/0xa10 fs/fs-writeback.c:2754 2 locks held by syz-executor/7154: #0: ffff8880281fc0e0 (&type->s_umount_key#31){++++}-{3:3}, at: deactivate_super+0xa0/0xd0 fs/super.c:362 #1: ffff888024a5a7d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:362 [inline] #1: ffff888024a5a7d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0x1a9/0xa10 fs/fs-writeback.c:2754 1 lock held by syz-executor/9301: #0: ffffffff8dd47de8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline] #0: ffffffff8dd47de8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x824/0xfc0 net/core/rtnetlink.c:6154 1 lock held by syz-executor/9333: #0: ffffffff8dd47de8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline] #0: ffffffff8dd47de8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x824/0xfc0 net/core/rtnetlink.c:6154 2 locks held by syz.9.1117/9634: #0: ffffffff8dd3af10 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x32e/0x5b0 net/core/net_namespace.c:504 #1: ffffffff8cb33140 (rcu_state.barrier_mutex){+.+.}-{3:3}, at: rcu_barrier+0x48/0x600 kernel/rcu/tree.c:4023 1 lock held by syz.5.1123/9671: #0: ffffffff8dd47de8 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:698 [inline] #0: ffffffff8dd47de8 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x3d/0x1b0 drivers/net/tun.c:3492 2 locks held by dhcpcd-run-hook/9697: ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 28 Comm: khungtaskd Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 Call Trace: dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106 nmi_cpu_backtrace+0x3e6/0x460 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x1d4/0x450 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline] watchdog+0xeee/0xf30 kernel/hung_task.c:377 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 9697 Comm: sed Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 RIP: 0010:get_current kernel/rcu/tree_plugin.h:401 [inline] RIP: 0010:rcu_preempt_read_enter kernel/rcu/tree_plugin.h:379 [inline] RIP: 0010:__rcu_read_lock+0x0/0x50 kernel/rcu/tree_plugin.h:402 Code: fb ff ff 44 89 f1 80 e1 07 38 c1 0f 8c 0f fb ff ff 4c 89 f7 e8 e1 47 66 00 e9 02 fb ff ff 66 2e 0f 1f 84 00 00 00 00 00 66 90 <53> 65 48 8b 1d 57 35 95 7e 48 81 c3 3c 04 00 00 48 89 d8 48 c1 e8 RSP: 0018:ffffc90003fd6fc8 EFLAGS: 00000293 RAX: ffffffff818f1476 RBX: 00007ff9655da242 RCX: ffff88802abb0000 RDX: 0000000000000000 RSI: ffffffff8adf1180 RDI: 00007ff9655da242 RBP: 0000000000000001 R08: 0000000000000004 R09: 000000000000000f R10: dffffc0000000000 R11: fffff520007fae19 R12: ffff88802abb0000 R13: ffff8880174c5000 R14: 00007ff9655da242 R15: 1ffff920007fae16 FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ff9655b14e8 CR3: 000000005e88b000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: rcu_read_lock include/linux/rcupdate.h:789 [inline] is_bpf_text_address+0x1b/0x2a0 kernel/bpf/core.c:735 kernel_text_address+0x9c/0xd0 kernel/extable.c:125 __kernel_text_address+0x9/0x30 kernel/extable.c:79 unwind_get_return_address+0x49/0x80 arch/x86/kernel/unwind_orc.c:323 arch_stack_walk+0xf2/0x140 arch/x86/kernel/stacktrace.c:26 stack_trace_save+0xa6/0xf0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:53 __kasan_slab_alloc+0x6b/0x80 mm/kasan/common.c:329 kasan_slab_alloc include/linux/kasan.h:201 [inline] slab_post_alloc_hook+0x4b/0x480 mm/slab.h:737 kmem_cache_alloc_bulk+0x3ba/0x4e0 mm/slub.c:3880 mt_alloc_bulk lib/maple_tree.c:159 [inline] mas_alloc_nodes+0x449/0x890 lib/maple_tree.c:1301 mas_node_count_gfp lib/maple_tree.c:1361 [inline] mas_preallocate+0x161/0x3c0 lib/maple_tree.c:5809 __vma_adjust+0x30d/0x1cd0 mm/mmap.c:724 vma_adjust include/linux/mm.h:2810 [inline] __split_vma+0x3a7/0x500 mm/mmap.c:-1 do_mas_align_munmap+0x397/0x12b0 mm/mmap.c:2480 do_mas_munmap+0x240/0x2b0 mm/mmap.c:2650 __mmap_region mm/mmap.c:2698 [inline] mmap_region+0x6e0/0x1ca0 mm/mmap.c:2916 do_mmap+0x964/0xfd0 mm/mmap.c:1436 vm_mmap_pgoff+0x1c1/0x2d0 mm/util.c:520 ksys_mmap_pgoff+0x516/0x6f0 mm/mmap.c:1482 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7ff9655da242 Code: 08 00 04 00 00 eb e2 90 41 f7 c1 ff 0f 00 00 75 27 55 89 cd 53 48 89 fb 48 85 ff 74 33 41 89 ea 48 89 df b8 09 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 5e 5b 5d c3 0f 1f 00 c7 05 46 40 01 00 16 00 RSP: 002b:00007ffee878fb48 EFLAGS: 00000206 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 00007ff96533c000 RCX: 00007ff9655da242 RDX: 0000000000000005 RSI: 000000000014e000 RDI: 00007ff96533c000 RBP: 0000000000000812 R08: 0000000000000003 R09: 0000000000028000 R10: 0000000000000812 R11: 0000000000000206 R12: 00007ffee878fb98 R13: 00007ff9655b65f0 R14: 00007ffee8790380 R15: 00000fffdd0f1f6c