INFO: task kworker/u8:7:1165 blocked for more than 143 seconds. Not tainted 6.16.0-rc4-syzkaller-00108-g17bbde2e1716 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u8:7 state:D stack:22504 pid:1165 tgid:1165 ppid:2 task_flags:0x4208060 flags:0x00004000 Workqueue: writeback wb_workfn (flush-7:5) Call Trace: context_switch kernel/sched/core.c:5396 [inline] __schedule+0x16a2/0x4cb0 kernel/sched/core.c:6785 __schedule_loop kernel/sched/core.c:6863 [inline] schedule+0x165/0x360 kernel/sched/core.c:6878 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6935 __mutex_lock_common kernel/locking/mutex.c:679 [inline] __mutex_lock+0x724/0xe80 kernel/locking/mutex.c:747 jfs_commit_inode+0x1ca/0x530 fs/jfs/inode.c:102 jfs_write_inode+0x145/0x220 fs/jfs/inode.c:132 write_inode fs/fs-writeback.c:1525 [inline] __writeback_single_inode+0x6f1/0xff0 fs/fs-writeback.c:1745 writeback_sb_inodes+0x6b5/0x1000 fs/fs-writeback.c:1976 __writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:2047 wb_writeback+0x44f/0xaf0 fs/fs-writeback.c:2158 wb_check_old_data_flush fs/fs-writeback.c:2262 [inline] wb_do_writeback fs/fs-writeback.c:2315 [inline] wb_workfn+0xaef/0xef0 fs/fs-writeback.c:2343 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3321 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402 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 Showing all locks held in the system: 1 lock held by khungtaskd/31: #0: ffffffff8e13ee20 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8e13ee20 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8e13ee20 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6770 2 locks held by kworker/u8:6/1147: 4 locks held by kworker/u8:7/1165: #0: ffff8881436b2148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline] #0: ffff8881436b2148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3321 #1: ffffc90003cdfbc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline] #1: ffffc90003cdfbc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3321 #2: ffff888024ca60e0 (&type->s_umount_key#111){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:563 #3: ffff88804ec7afe0 (&jfs_ip->commit_mutex){+.+.}-{4:4}, at: jfs_commit_inode+0x1ca/0x530 fs/jfs/inode.c:102 2 locks held by getty/5580: #0: ffff8880314920a0 (&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+0x43e/0x1400 drivers/tty/n_tty.c:2222 2 locks held by kworker/0:3/5878: #0: ffff8880b8639e18 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:606 #1: ffffc900053a7bc0 ((work_completion)(&(&hwstats->traffic_dw)->work)){+.+.}-{0:0}, at: psi_task_switch+0x39e/0x6d0 kernel/sched/psi.c:987 4 locks held by syz.5.266/8343: 3 locks held by syz-executor/9429: 2 locks held by syz.6.434/9904: #0: ffff888024ca60e0 (&type->s_umount_key#111){++++}-{4:4}, at: __super_lock fs/super.c:59 [inline] #0: ffff888024ca60e0 (&type->s_umount_key#111){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:121 #1: ffff8880250847d0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:387 [inline] #1: ffff8880250847d0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: sync_inodes_sb+0x19f/0xa10 fs/fs-writeback.c:2831 2 locks held by syz.2.474/10309: #0: ffff888024ca60e0 (&type->s_umount_key#111){++++}-{4:4}, at: __super_lock fs/super.c:59 [inline] #0: ffff888024ca60e0 (&type->s_umount_key#111){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:121 #1: ffff8880250847d0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:387 [inline] #1: ffff8880250847d0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: sync_inodes_sb+0x19f/0xa10 fs/fs-writeback.c:2831 2 locks held by syz.7.568/11050: #0: ffff888024ca60e0 (&type->s_umount_key#111){++++}-{4:4}, at: __super_lock fs/super.c:59 [inline] #0: ffff888024ca60e0 (&type->s_umount_key#111){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:121 #1: ffff8880250847d0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:387 [inline] #1: ffff8880250847d0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: sync_inodes_sb+0x19f/0xa10 fs/fs-writeback.c:2831 1 lock held by sed/11129: ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.16.0-rc4-syzkaller-00108-g17bbde2e1716 #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: 11128 Comm: dhcpcd-run-hook Not tainted 6.16.0-rc4-syzkaller-00108-g17bbde2e1716 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:kasan_check_byte include/linux/kasan.h:399 [inline] RIP: 0010:lock_acquire+0x7d/0x360 kernel/locking/lockdep.c:5845 Code: 05 f8 bf 01 0e 73 16 e8 51 f1 08 00 84 c0 75 0d f6 05 3e b3 eb 0d 01 0f 84 d7 01 00 00 83 3d 19 f1 01 0e 00 0f 84 f0 00 00 00 <48> 8b b4 24 90 00 00 00 4c 89 ef e8 43 5a 83 00 83 3d fc f0 01 0e RSP: 0018:ffffc90003eaf318 EFLAGS: 00000202 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 3fc2b7134fa4bd00 RDX: 0000000000000000 RSI: ffffffff8be1b960 RDI: ffffffff8be1b920 RBP: ffffffff81728af5 R08: 0000000000000000 R09: 0000000000000000 R10: ffffc90003eaf4d8 R11: ffffffff81ace5d0 R12: 0000000000000002 R13: ffffffff8e13ee20 R14: 0000000000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888125c84000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fd99fbe87d0 CR3: 000000000df38000 CR4: 00000000003526f0 Call Trace: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:841 [inline] class_rcu_constructor include/linux/rcupdate.h:1155 [inline] unwind_next_frame+0xc2/0x2390 arch/x86/kernel/unwind_orc.c:479 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:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:247 [inline] __kasan_slab_free+0x62/0x70 mm/kasan/common.c:264 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2381 [inline] slab_free mm/slub.c:4643 [inline] kmem_cache_free+0x18f/0x400 mm/slub.c:4745 anon_vma_chain_free mm/rmap.c:147 [inline] unlink_anon_vmas+0x614/0x670 mm/rmap.c:447 free_pgtables+0x587/0xaf0 mm/memory.c:381 exit_mmap+0x444/0xb50 mm/mmap.c:1295 __mmput+0x118/0x420 kernel/fork.c:1121 exit_mm+0x1da/0x2c0 kernel/exit.c:581 do_exit+0x648/0x22e0 kernel/exit.c:952 do_group_exit+0x21c/0x2d0 kernel/exit.c:1105 __do_sys_exit_group kernel/exit.c:1116 [inline] __se_sys_exit_group kernel/exit.c:1114 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1114 x64_sys_call+0x21ba/0x21c0 arch/x86/include/generated/asm/syscalls_64.h:232 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: 0033:0x7fd99fae66c5 Code: Unable to access opcode bytes at 0x7fd99fae669b. RSP: 002b:00007ffdad1e2b58 EFLAGS: 00000202 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 00007ffdad1e2e04 RCX: 00007fd99fae66c5 RDX: 00000000000000e7 RSI: ffffffffffffff88 RDI: 0000000000000000 RBP: 0000000000000003 R08: 00007ffdad1e2c50 R09: 0000000000000002 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 R13: 00007ffdad1e2e90 R14: 00007fd99fcf6000 R15: 000055dd6e4a5d98