INFO: task kworker/u8:4:82 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:kworker/u8:4 state:D stack:21064 pid:82 tgid:82 ppid:2 task_flags:0x4208060 flags:0x00004000 Workqueue: writeback wb_workfn (flush-7:4) 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 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6917 __mutex_lock_common kernel/locking/mutex.c:678 [inline] __mutex_lock+0x724/0xe80 kernel/locking/mutex.c:746 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+0x6ee/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+0xade/0x17a0 kernel/workqueue.c:3319 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400 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 INFO: task syz.0.96:6624 blocked for more than 144 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.0.96 state:D stack:26216 pid:6624 tgid:6622 ppid:5819 task_flags:0x400040 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 sync_inodes_sb+0x1bb/0xa10 fs/fs-writeback.c:2833 iterate_supers+0xb8/0x180 fs/super.c:934 ksys_sync+0x94/0x150 fs/sync.c:102 __ia32_sys_sync+0xe/0x20 fs/sync.c:113 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: 0033:0x7fb9de98e969 RSP: 002b:00007fb9df820038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2 RAX: ffffffffffffffda RBX: 00007fb9debb6080 RCX: 00007fb9de98e969 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007fb9debb6080 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fb9debb6080 R15: 00007fff68ef6068 Showing all locks held in the system: 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 4 locks held by kworker/u8:4/82: #0: ffff888141aae948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline] #0: ffff888141aae948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b1/0x17a0 kernel/workqueue.c:3319 #1: ffffc900015b7c60 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline] #1: ffffc900015b7c60 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ec/0x17a0 kernel/workqueue.c:3319 #2: ffff88807dcfe0e0 (&type->s_umount_key#51){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:562 #3: ffff888059b9afe0 (&jfs_ip->commit_mutex){+.+.}-{4:4}, at: jfs_commit_inode+0x1ca/0x530 fs/jfs/inode.c:102 2 locks held by getty/5580: #0: ffff888030c840a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc90002ffe2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222 5 locks held by syz.4.28/6121: 2 locks held by syz.0.96/6624: #0: ffff88807dcfe0e0 (&type->s_umount_key#51){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff88807dcfe0e0 (&type->s_umount_key#51){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:120 #1: ffff888142fca7d0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:387 [inline] #1: ffff888142fca7d0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: sync_inodes_sb+0x19f/0xa10 fs/fs-writeback.c:2831 1 lock held by syz-executor/6883: 2 locks held by syz.1.350/8718: #0: ffff88807dcfe0e0 (&type->s_umount_key#51){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff88807dcfe0e0 (&type->s_umount_key#51){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:120 #1: ffff888142fca7d0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:387 [inline] #1: ffff888142fca7d0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: sync_inodes_sb+0x19f/0xa10 fs/fs-writeback.c:2831 ============================================= NMI backtrace for cpu 0 CPU: 0 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 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 6121 Comm: syz.4.28 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:rdtsc_ordered arch/x86/include/asm/msr.h:217 [inline] RIP: 0010:__pvclock_clocksource_read arch/x86/kernel/pvclock.c:77 [inline] RIP: 0010:pvclock_clocksource_read_nowd+0x42/0xf0 arch/x86/kernel/pvclock.c:120 Code: 56 44 89 f1 48 d3 e0 83 e5 fe 4c 89 3c 24 48 f7 24 24 48 0f ac d0 20 48 8b 4f 10 0f b6 57 1d 8b 37 39 f5 89 f5 74 70 0f 01 f9 <66> 90 48 89 c1 48 89 d0 48 c1 e0 20 48 09 c8 48 2b 47 08 44 8b 7f RSP: 0000:ffffc90000a089a8 EFLAGS: 00000002 RAX: 000000006cef9caa RBX: ffff8880b89399c0 RCX: 0000000000000001 RDX: 0000000000000093 RSI: ffffffff8d924cb5 RDI: ffffffff9278b040 RBP: 0000000000000004 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff5200014114c R12: ffff8880b89399c0 R13: dffffc0000000000 R14: ffffc90000a08a60 R15: 1ffff92000141148 FS: 00007f301160a6c0(0000) GS:ffff8881261f6000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f3fb5980178 CR3: 00000000247e4000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: kvm_sched_clock_read+0x11/0x20 arch/x86/kernel/kvmclock.c:91 sched_clock+0x17/0x60 arch/x86/kernel/tsc.c:287 sched_clock_cpu+0x74/0x430 kernel/sched/clock.c:394 update_rq_clock+0x100/0x5b0 kernel/sched/core.c:814 ttwu_queue kernel/sched/core.c:3999 [inline] try_to_wake_up+0x731/0x1290 kernel/sched/core.c:4328 call_timer_fn+0x17e/0x5f0 kernel/time/timer.c:1789 expire_timers kernel/time/timer.c:1840 [inline] __run_timers kernel/time/timer.c:2414 [inline] __run_timer_base+0x61a/0x860 kernel/time/timer.c:2426 run_timer_base kernel/time/timer.c:2435 [inline] run_timer_softirq+0xb7/0x180 kernel/time/timer.c:2445 handle_softirqs+0x283/0x870 kernel/softirq.c:579 __do_softirq kernel/softirq.c:613 [inline] invoke_softirq kernel/softirq.c:453 [inline] __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:680 irq_exit_rcu+0x9/0x30 kernel/softirq.c:696 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1049 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:dtSplitRoot+0x7ab/0x16c0 fs/jfs/jfs_dtree.c:1981 Code: e5 05 4c 01 ed 49 89 ed 49 c1 ed 03 43 0f b6 44 25 00 84 c0 75 2b 44 0f b6 75 00 45 84 f6 78 34 e8 aa c0 86 fe 4c 8b 6c 24 10 b6 e8 9e c0 86 fe 89 ee 48 c7 c7 40 8b 36 8e e8 e0 01 ae 01 eb RSP: 0000:ffffc9000b7476c8 EFLAGS: 00000246 RAX: ffffffff83393036 RBX: 0000000000000004 RCX: 0000000000080000 RDX: ffffc9000c99d000 RSI: 000000000007ffff RDI: 0000000000080000 RBP: ffff88802fcb8000 R08: 00000000000001ff R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: dffffc0000000000 R13: ffff88802fcb8000 R14: 0000000000000000 R15: 1ffff11005f97002 dtSplitUp fs/jfs/jfs_dtree.c:993 [inline] dtInsert+0xef8/0x5f40 fs/jfs/jfs_dtree.c:871 jfs_symlink+0x715/0xe60 fs/jfs/namei.c:1020 vfs_symlink+0x140/0x2f0 fs/namei.c:4723 do_symlinkat+0x1b1/0x3f0 fs/namei.c:4749 __do_sys_symlink fs/namei.c:4770 [inline] __se_sys_symlink fs/namei.c:4768 [inline] __x64_sys_symlink+0x7a/0x90 fs/namei.c:4768 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: 0033:0x7f301078e969 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 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:00007f301160a038 EFLAGS: 00000246 ORIG_RAX: 0000000000000058 RAX: ffffffffffffffda RBX: 00007f30109b5fa0 RCX: 00007f301078e969 RDX: 0000000000000000 RSI: 0000200000000cc0 RDI: 000020000000a900 RBP: 00007f3010810ab1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f30109b5fa0 R15: 00007ffc2a955528