INFO: task syz-executor:6204 blocked for more than 143 seconds. Not tainted 6.15.0-rc4-syzkaller-00052-g4f79eaa2ceac #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:16680 pid:6204 tgid:6204 ppid:1 task_flags:0x400140 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x168f/0x4c70 kernel/sched/core.c:6767 __schedule_loop kernel/sched/core.c:6845 [inline] schedule+0x165/0x360 kernel/sched/core.c:6860 wb_wait_for_completion+0x15f/0x260 fs/fs-writeback.c:216 __writeback_inodes_sb_nr+0x1f6/0x250 fs/fs-writeback.c:2747 sync_filesystem+0xa3/0x230 fs/sync.c:54 generic_shutdown_super+0x6f/0x2c0 fs/super.c:621 bch2_kill_sb+0x41/0x50 fs/bcachefs/fs.c:2620 deactivate_locked_super+0xb9/0x130 fs/super.c:473 cleanup_mnt+0x425/0x4c0 fs/namespace.c:1435 task_work_run+0x1d1/0x260 kernel/task_work.c:227 resume_user_mode_work+0x5e/0x80 include/linux/resume_user_mode.h:50 exit_to_user_mode_loop kernel/entry/common.c:114 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0x9a/0x120 kernel/entry/common.c:218 do_syscall_64+0x103/0x210 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f9aaaf8fc97 RSP: 002b:00007ffecc210648 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 00007f9aab01089d RCX: 00007f9aaaf8fc97 RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffecc210700 RBP: 00007ffecc210700 R08: 0000000000000000 R09: 0000000000000000 R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffecc211790 R13: 00007f9aab01089d R14: 0000000000025f47 R15: 00007ffecc2117d0 Showing all locks held in the system: 3 locks held by kworker/u8:1/13: #0: ffff88801a089148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline] #0: ffff88801a089148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9b1/0x17a0 kernel/workqueue.c:3319 #1: ffffc90000127c60 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline] #1: ffffc90000127c60 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x9ec/0x17a0 kernel/workqueue.c:3319 #2: ffffffff8f2e2008 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:303 1 lock held by khungtaskd/31: #0: ffffffff8df3b860 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8df3b860 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8df3b860 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6764 2 locks held by kworker/u8:4/69: #0: ffff8880b89399d8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:605 #1: ffff8880b8923b08 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x39e/0x6d0 kernel/sched/psi.c:987 2 locks held by kworker/u8:6/1152: 5 locks held by kworker/u8:7/1168: #0: ffff88801aef3948 ( (wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline] (wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x9b1/0x17a0 kernel/workqueue.c:3319 #1: ffffc900041afc60 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline] #1: ffffc900041afc60 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ec/0x17a0 kernel/workqueue.c:3319 #2: ffffffff8f2d54d0 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0x145/0xbd0 net/core/net_namespace.c:608 #3: ffffffff8f2e2008 (rtnl_mutex){+.+.}-{4:4}, at: default_device_exit_batch+0xdc/0x890 net/core/dev.c:12524 #4: ffffffff8df41338 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:304 [inline] #4: ffffffff8df41338 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2f4/0x730 kernel/rcu/tree_exp.h:998 2 locks held by kworker/u8:10/2993: #0: ffff888143ea2148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline] #0: ffff888143ea2148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b1/0x17a0 kernel/workqueue.c:3319 #1: ffffc9000bb97c60 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline] #1: ffffc9000bb97c60 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ec/0x17a0 kernel/workqueue.c:3319 1 lock held by dhcpcd/5486: #0: ffffffff8f2e2008 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8f2e2008 (rtnl_mutex){+.+.}-{4:4}, at: inet6_rtm_deladdr+0x20f/0x330 net/ipv6/addrconf.c:4800 2 locks held by getty/5577: #0: ffff8880350820a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000333b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222 1 lock held by syz-executor/6204: #0: ffff88806bbd20e0 (&type->s_umount_key#57){++++}-{4:4}, at: __super_lock fs/super.c:56 [inline] #0: ffff88806bbd20e0 (&type->s_umount_key#57){++++}-{4:4}, at: __super_lock_excl fs/super.c:71 [inline] #0: ffff88806bbd20e0 (&type->s_umount_key#57){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:505 1 lock held by syz.0.316/8690: #0: ffff88806bbd20e0 (&type->s_umount_key#57){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff88806bbd20e0 (&type->s_umount_key#57){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:120 1 lock held by syz.3.349/9027: #0: ffff88806bbd20e0 (&type->s_umount_key#57){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff88806bbd20e0 (&type->s_umount_key#57){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:120 7 locks held by syz-executor/9354: #0: ffff888031ecc420 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:3041 [inline] #0: ffff888031ecc420 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x211/0xa90 fs/read_write.c:680 #1: ffff88807eeb4488 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1e0/0x4f0 fs/kernfs/file.c:325 #2: ffff888026e1a0f8 (kn->active#49){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x203/0x4f0 fs/kernfs/file.c:326 #3: ffffffff8eb82128 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x360 drivers/net/netdevsim/bus.c:216 #4: ffff88805b2150e8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:922 [inline] #4: ffff88805b2150e8 (&dev->mutex){....}-{4:4}, at: __device_driver_lock drivers/base/dd.c:1094 [inline] #4: ffff88805b2150e8 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0xb6/0x7c0 drivers/base/dd.c:1292 #5: ffff88805b217250 (&devlink->lock_key#3){+.+.}-{4:4}, at: nsim_drv_remove+0x50/0x160 drivers/net/netdevsim/dev.c:1675 #6: ffffffff8f2e2008 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #6: ffffffff8f2e2008 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_dev_lock+0x257/0x2f0 net/core/dev.c:2089 1 lock held by syz-executor/9462: #0: ffffffff8f2e2008 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #0: ffffffff8f2e2008 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #0: ffffffff8f2e2008 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8db/0x1c70 net/core/rtnetlink.c:4064 2 locks held by syz.9.406/9549: 1 lock held by syz.6.407/9561: #0: ffffffff8df41338 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:336 [inline] #0: ffffffff8df41338 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b7/0x730 kernel/rcu/tree_exp.h:998 ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.15.0-rc4-syzkaller-00052-g4f79eaa2ceac #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025 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:274 [inline] watchdog+0xfee/0x1030 kernel/hung_task.c:437 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153 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: 9560 Comm: syz.4.403 Not tainted 6.15.0-rc4-syzkaller-00052-g4f79eaa2ceac #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025 RIP: 0010:lockdep_enabled kernel/locking/lockdep.c:118 [inline] RIP: 0010:lock_acquire+0x94/0x360 kernel/locking/lockdep.c:5842 Code: 0f 84 d7 01 00 00 83 3d 79 cc df 0d 00 0f 84 f0 00 00 00 48 8b b4 24 90 00 00 00 4c 89 ef e8 33 5b 81 00 83 3d 5c cc df 0d 00 <0f> 84 fa 00 00 00 65 8b 05 3f 2f d4 10 85 c0 0f 85 eb 00 00 00 65 RSP: 0018:ffffc900045cf428 EFLAGS: 00000202 RAX: 0000000000000001 RBX: 0000000000000000 RCX: d59bdfeadf28fc00 RDX: 0000000000000000 RSI: ffffffff822a7087 RDI: 1ffffffff1be770c RBP: ffffffff822a706a R08: 0000000000000000 R09: 0000000000000000 R10: dffffc0000000000 R11: ffffed100687e460 R12: 0000000000000002 R13: ffffffff8df3b860 R14: 0000000000000000 R15: 0000000000000000 FS: 00007f9629b5d6c0(0000) GS:ffff888126100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffde5b9fee8 CR3: 000000007a880000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:841 [inline] __page_table_check_zero+0xd7/0x510 mm/page_table_check.c:138 page_table_check_free include/linux/page_table_check.h:41 [inline] free_pages_prepare mm/page_alloc.c:1263 [inline] free_unref_folios+0xb84/0x1490 mm/page_alloc.c:2782 folios_put_refs+0x559/0x640 mm/swap.c:992 folio_batch_release include/linux/pagevec.h:101 [inline] shmem_undo_range+0x49e/0x14b0 mm/shmem.c:1125 shmem_truncate_range mm/shmem.c:1237 [inline] shmem_evict_inode+0x272/0xa70 mm/shmem.c:1365 evict+0x501/0x9c0 fs/inode.c:810 __dentry_kill+0x209/0x660 fs/dcache.c:660 dput+0x19f/0x2b0 fs/dcache.c:902 __fput+0x68e/0xa70 fs/file_table.c:473 fput_close_sync+0x119/0x200 fs/file_table.c:570 __do_sys_close fs/open.c:1581 [inline] __se_sys_close fs/open.c:1566 [inline] __x64_sys_close+0x7f/0x110 fs/open.c:1566 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f9628d8d5ca Code: 48 3d 00 f0 ff ff 77 48 c3 0f 1f 80 00 00 00 00 48 83 ec 18 89 7c 24 0c e8 43 91 02 00 8b 7c 24 0c 89 c2 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 36 89 d7 89 44 24 0c e8 a3 91 02 00 8b 44 24 RSP: 002b:00007f9629b5ce00 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: ffffffffffffffda RBX: 00000000ffffffff RCX: 00007f9628d8d5ca RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000006 RBP: 0000000000000010 R08: 0000000000000000 R09: 0000000000005598 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000006 R13: 00007f9629b5cef0 R14: 00007f9629b5ceb0 R15: 00007f961e600000