INFO: task syz.2.261:9037 blocked for more than 143 seconds. Not tainted 6.15.0-rc7-syzkaller-00175-g0f8c0258bf04 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.2.261 state:D stack:25144 pid:9037 tgid:9034 ppid:7014 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 io_schedule+0x81/0xe0 kernel/sched/core.c:7742 bit_wait_io+0x11/0xd0 kernel/sched/wait_bit.c:247 __wait_on_bit_lock+0xec/0x4f0 kernel/sched/wait_bit.c:90 out_of_line_wait_on_bit_lock+0x123/0x170 kernel/sched/wait_bit.c:117 lock_buffer include/linux/buffer_head.h:434 [inline] hfs_mdb_commit+0xc8e/0x1160 fs/hfs/mdb.c:325 hfs_sync_fs+0x15/0x20 fs/hfs/super.c:37 sync_filesystem+0xee/0x230 fs/sync.c:56 hfs_reconfigure+0x66/0x270 fs/hfs/super.c:119 reconfigure_super+0x224/0x890 fs/super.c:1083 do_remount fs/namespace.c:3365 [inline] path_mount+0xd18/0xfe0 fs/namespace.c:4200 do_mount fs/namespace.c:4221 [inline] __do_sys_mount fs/namespace.c:4432 [inline] __se_sys_mount+0x317/0x410 fs/namespace.c:4409 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: 0033:0x7f170559010a RSP: 002b:00007f1706370e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007f1706370ef0 RCX: 00007f170559010a RDX: 0000200000000f40 RSI: 0000200000000f00 RDI: 0000000000000000 RBP: 0000200000000f40 R08: 00007f1706370ef0 R09: 0000000001258438 R10: 0000000001258438 R11: 0000000000000246 R12: 0000200000000f00 R13: 00007f1706370eb0 R14: 0000000000000000 R15: 0000200000000f80 Showing all locks held in the system: 1 lock held by pool_workqueue_/3: #0: ffffffff8df439b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:336 [inline] #0: ffffffff8df439b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b7/0x730 kernel/rcu/tree_exp.h:998 1 lock held by khungtaskd/31: #0: ffffffff8df3dee0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8df3dee0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8df3dee0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6764 3 locks held by kworker/u8:5/140: 3 locks held by kworker/u8:7/4467: 2 locks held by getty/5581: #0: ffff8880307520a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc900033332f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222 2 locks held by udevd/5817: 2 locks held by kworker/0:6/5914: #0: ffff88801a081548 ((wq_completion)events_long){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline] #0: ffff88801a081548 ((wq_completion)events_long){+.+.}-{0:0}, at: process_scheduled_works+0x9b1/0x17a0 kernel/workqueue.c:3319 #1: ffffc9000b1c7c60 ((work_completion)(&(&sbi->mdb_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline] #1: ffffc9000b1c7c60 ((work_completion)(&(&sbi->mdb_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ec/0x17a0 kernel/workqueue.c:3319 1 lock held by udevd/6566: 1 lock held by syz.2.261/9037: #0: ffff88804ac820e0 (&type->s_umount_key#104){+.+.}-{4:4}, at: do_remount fs/namespace.c:3362 [inline] #0: ffff88804ac820e0 (&type->s_umount_key#104){+.+.}-{4:4}, at: path_mount+0xcd2/0xfe0 fs/namespace.c:4200 2 locks held by syz-executor/10708: #0: ffff88807ecee0e0 (&type->s_umount_key#69){+.+.}-{4:4}, at: __super_lock fs/super.c:56 [inline] #0: ffff88807ecee0e0 (&type->s_umount_key#69){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:71 [inline] #0: ffff88807ecee0e0 (&type->s_umount_key#69){+.+.}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:505 #1: ffffffff8df439b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:304 [inline] #1: ffffffff8df439b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2f4/0x730 kernel/rcu/tree_exp.h:998 2 locks held by syz.1.479/11460: #0: ffff8880492640e0 (&type->s_umount_key#64/1){+.+.}-{4:4}, at: alloc_super+0x204/0x970 fs/super.c:344 #1: ffffffff8dde54a8 (wq_pool_mutex){+.+.}-{4:4}, at: apply_wqattrs_lock kernel/workqueue.c:5179 [inline] #1: ffffffff8dde54a8 (wq_pool_mutex){+.+.}-{4:4}, at: __alloc_workqueue+0x9eb/0x1b70 kernel/workqueue.c:5734 2 locks held by syz.7.482/11463: 2 locks held by syz.9.480/11468: 3 locks held by dhcpcd-run-hook/11495: ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.15.0-rc7-syzkaller-00175-g0f8c0258bf04 #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:274 [inline] watchdog+0xfee/0x1030 kernel/hung_task.c:437 kthread+0x711/0x8a0 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: 11468 Comm: syz.9.480 Not tainted 6.15.0-rc7-syzkaller-00175-g0f8c0258bf04 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:check_preemption_disabled+0x40/0x120 lib/smp_processor_id.c:55 Code: 08 65 8b 05 56 ee 22 07 65 8b 0d 4b ee 22 07 f7 c1 ff ff ff 7f 74 23 65 48 8b 0d 2b ee 22 07 48 3b 4c 24 08 0f 85 cc 00 00 00 <48> 83 c4 10 5b 41 5e 41 5f 5d e9 51 b5 02 00 cc 48 c7 04 24 00 00 RSP: 0018:ffffc90004cef6a0 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffffffff849bb09d RCX: 4b96657eef4ef300 RDX: ffff88802eb3bc00 RSI: ffffffff8bc122e0 RDI: ffffffff8bc122a0 RBP: 0000000000000000 R08: ffffffff999a36e7 R09: 1ffffffff33346dc R10: dffffc0000000000 R11: fffffbfff33346dd R12: dffffc0000000000 R13: 0000000000000cc0 R14: 0000000000000001 R15: ffffffff999a36e4 FS: 00007f7a6b6216c0(0000) GS:ffff8881260f6000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f961e5f2b60 CR3: 0000000045548000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: rcu_is_watching_curr_cpu include/linux/context_tracking.h:128 [inline] rcu_is_watching+0x15/0xb0 kernel/rcu/tree.c:736 rcu_read_unlock include/linux/rcupdate.h:869 [inline] blk_cgroup_congested+0x17d/0x210 block/blk-cgroup.c:2263 __folio_throttle_swaprate+0x80/0x1c0 mm/swapfile.c:3923 folio_throttle_swaprate include/linux/swap.h:634 [inline] shmem_add_to_page_cache+0x72c/0xb10 mm/shmem.c:898 shmem_alloc_and_add_folio+0x846/0xf60 mm/shmem.c:1919 shmem_get_folio_gfp+0x597/0x15f0 mm/shmem.c:2533 shmem_get_folio mm/shmem.c:2639 [inline] shmem_write_begin+0xf7/0x2b0 mm/shmem.c:3289 generic_perform_write+0x2c4/0x910 mm/filemap.c:4103 shmem_file_write_iter+0xf8/0x120 mm/shmem.c:3464 new_sync_write fs/read_write.c:591 [inline] vfs_write+0x54b/0xa90 fs/read_write.c:684 ksys_write+0x145/0x250 fs/read_write.c:736 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: 0033:0x7f7a6a78d41f Code: 89 54 24 18 48 89 74 24 10 89 7c 24 08 e8 f9 92 02 00 48 8b 54 24 18 48 8b 74 24 10 41 89 c0 8b 7c 24 08 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 31 44 89 c7 48 89 44 24 08 e8 4c 93 02 00 48 RSP: 002b:00007f7a6b620df0 EFLAGS: 00000293 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000001000000 RCX: 00007f7a6a78d41f RDX: 0000000001000000 RSI: 00007f7a60000000 RDI: 0000000000000003 RBP: 0000000000000000 R08: 0000000000000000 R09: 00000000000050ed R10: 000020000000a2c2 R11: 0000000000000293 R12: 0000000000000003 R13: 00007f7a6b620ef0 R14: 00007f7a6b620eb0 R15: 00007f7a60000000