INFO: task syz-executor:7394 blocked for more than 143 seconds. Tainted: G W syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:18304 pid:7394 tgid:7394 ppid:1 task_flags:0x400140 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x16f3/0x4c20 kernel/sched/core.c:6961 __schedule_loop kernel/sched/core.c:7043 [inline] schedule+0x165/0x360 kernel/sched/core.c:7058 schedule_timeout+0x9a/0x270 kernel/time/sleep_timeout.c:75 do_wait_for_common kernel/sched/completion.c:100 [inline] __wait_for_common kernel/sched/completion.c:121 [inline] wait_for_common kernel/sched/completion.c:132 [inline] wait_for_completion+0x2bf/0x5d0 kernel/sched/completion.c:153 kthread_stop+0x194/0x5c0 kernel/kthread.c:790 bch2_copygc_stop+0x4b/0x120 fs/bcachefs/movinggc.c:438 __bch2_fs_read_only+0x47/0x5b0 fs/bcachefs/super.c:280 bch2_fs_read_only+0x42a/0xb00 fs/bcachefs/super.c:366 __bch2_fs_stop+0x100/0x900 fs/bcachefs/super.c:677 generic_shutdown_super+0x135/0x2c0 fs/super.c:643 bch2_kill_sb+0x41/0x50 fs/bcachefs/fs.c:2618 deactivate_locked_super+0xb9/0x130 fs/super.c:474 cleanup_mnt+0x425/0x4c0 fs/namespace.c:1375 task_work_run+0x1d4/0x260 kernel/task_work.c:227 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] exit_to_user_mode_loop+0xec/0x110 kernel/entry/common.c:43 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline] do_syscall_64+0x2bd/0x3b0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fd474ecff17 RSP: 002b:00007ffe3ef450c8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 00007fd474f51c05 RCX: 00007fd474ecff17 RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffe3ef45180 RBP: 00007ffe3ef45180 R08: 0000000000000000 R09: 0000000000000000 R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffe3ef46210 R13: 00007fd474f51c05 R14: 000000000004a2a5 R15: 00007ffe3ef46250 INFO: lockdep is turned off. NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 39 Comm: khungtaskd Tainted: G W syzkaller #0 PREEMPT_{RT,(full)} Tainted: [W]=WARN Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 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] check_hung_uninterruptible_tasks kernel/hung_task.c:328 [inline] watchdog+0xf93/0xfe0 kernel/hung_task.c:491 kthread+0x70e/0x8a0 kernel/kthread.c:463 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: 10371 Comm: syz-executor Tainted: G W syzkaller #0 PREEMPT_{RT,(full)} Tainted: [W]=WARN Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:on_stack arch/x86/include/asm/stacktrace.h:58 [inline] RIP: 0010:stack_access_ok arch/x86/kernel/unwind_orc.c:393 [inline] RIP: 0010:deref_stack_reg arch/x86/kernel/unwind_orc.c:403 [inline] RIP: 0010:unwind_next_frame+0xb4c/0x2390 arch/x86/kernel/unwind_orc.c:585 Code: 66 10 48 b8 00 00 00 00 00 fc ff df 48 8b 4c 24 20 0f b6 04 01 84 c0 0f 85 85 13 00 00 41 83 3e 00 0f 95 c0 49 39 df 0f 96 c1 <20> c1 49 39 dc 0f 97 c0 20 c8 3c 01 75 18 48 8d 43 08 4c 39 f8 0f RSP: 0018:ffffc9000922f198 EFLAGS: 00000283 RAX: 0000000000000001 RBX: ffffc9000922ff50 RCX: 1ffff92001245e01 RDX: ffffffff904620b4 RSI: 0000000000000002 RDI: ffffffff8b620c20 RBP: 1ffff92001245e4e R08: 0000000000000001 R09: 0000000000000000 R10: ffffc9000922f2b8 R11: ffffffff81aae020 R12: ffffc90009230000 R13: 1ffff92001245e4f R14: ffffc9000922f268 R15: ffffc90009228000 FS: 0000555574a14500(0000) GS:ffff8881268c5000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f4973b8d000 CR3: 0000000053af6000 CR4: 00000000003526f0 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:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 unpoison_slab_object mm/kasan/common.c:330 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:356 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4180 [inline] slab_alloc_node mm/slub.c:4229 [inline] kmem_cache_alloc_lru_noprof+0x14c/0x310 mm/slub.c:4248 __d_alloc+0x36/0x7b0 fs/dcache.c:1690 d_alloc_parallel+0xe5/0x1600 fs/dcache.c:2549 __lookup_slow+0x11c/0x3d0 fs/namei.c:1793 ovl_lookup_upper fs/overlayfs/overlayfs.h:407 [inline] ovl_lookup_temp+0x1c2/0x2c0 fs/overlayfs/dir.c:71 ovl_whiteout fs/overlayfs/dir.c:108 [inline] ovl_cleanup_and_whiteout+0x2af/0x900 fs/overlayfs/dir.c:138 ovl_remove_and_whiteout fs/overlayfs/dir.c:796 [inline] ovl_do_remove+0x814/0xda0 fs/overlayfs/dir.c:915 vfs_unlink+0x397/0x660 fs/namei.c:4586 do_unlinkat+0x345/0x570 fs/namei.c:4650 __do_sys_unlink fs/namei.c:4696 [inline] __se_sys_unlink fs/namei.c:4694 [inline] __x64_sys_unlink+0x47/0x50 fs/namei.c:4694 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: 0033:0x7f560cdfe197 Code: 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 57 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffe556a36a8 EFLAGS: 00000206 ORIG_RAX: 0000000000000057 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f560cdfe197 RDX: 00007ffe556a36d0 RSI: 00007ffe556a3760 RDI: 00007ffe556a3760 RBP: 00007ffe556a3760 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000100 R11: 0000000000000206 R12: 00007ffe556a4850 R13: 00007f560ce81c05 R14: 000000000006da89 R15: 00007ffe556a6a10