INFO: task syz.2.368:8345 blocked for more than 143 seconds. Not tainted 6.15.0-rc4-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.2.368 state:D stack:27448 pid:8345 tgid:8344 ppid:5836 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 folio_wait_bit_common+0x6b0/0xb90 mm/filemap.c:1317 folio_wait_writeback+0xb0/0x100 mm/page-writeback.c:3149 __filemap_fdatawait_range+0x147/0x230 mm/filemap.c:539 filemap_fdatawait_keep_errors+0x31/0xd0 mm/filemap.c:633 wait_sb_inodes fs/fs-writeback.c:2714 [inline] sync_inodes_sb+0x7a9/0xa10 fs/fs-writeback.c:2836 iterate_supers+0xb5/0x180 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: 0033:0x7f3d42f8e969 RSP: 002b:00007f3d43e95038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2 RAX: ffffffffffffffda RBX: 00007f3d431b5fa0 RCX: 00007f3d42f8e969 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007f3d431b5fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f3d431b5fa0 R15: 00007ffe3ff38718 Showing all locks held in the system: 1 lock held by pool_workqueue_/3: 2 locks held by kworker/u8:1/13: 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 3 locks held by kworker/u8:7/3478: 3 locks held by udevd/5191: 2 locks held by getty/5579: #0: ffff88803070b0a0 (&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 3 locks held by udevd/5819: 1 lock held by syz.0.361/8306: #0: ffff88803527a420 (sb_writers#18){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:3041 [inline] #0: ffff88803527a420 (sb_writers#18){.+.+}-{0:0}, at: vfs_writev+0x274/0x9a0 fs/read_write.c:1053 1 lock held by bch-copygc/loop/8334: 2 locks held by syz.2.368/8345: #0: ffff88803527a0e0 (&type->s_umount_key#64){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff88803527a0e0 (&type->s_umount_key#64){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:120 #1: ffff88803527a948 (&s->s_sync_lock){+.+.}-{4:4}, at: wait_sb_inodes fs/fs-writeback.c:2653 [inline] #1: ffff88803527a948 (&s->s_sync_lock){+.+.}-{4:4}, at: sync_inodes_sb+0x255/0xa10 fs/fs-writeback.c:2836 2 locks held by syz.5.519/9709: #0: ffff88803527a0e0 (&type->s_umount_key#64){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff88803527a0e0 (&type->s_umount_key#64){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:120 #1: ffff88803527a948 (&s->s_sync_lock){+.+.}-{4:4}, at: wait_sb_inodes fs/fs-writeback.c:2653 [inline] #1: ffff88803527a948 (&s->s_sync_lock){+.+.}-{4:4}, at: sync_inodes_sb+0x255/0xa10 fs/fs-writeback.c:2836 2 locks held by syz.1.655/10993: 1 lock held by syz.7.654/10996: #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 5 locks held by syz.7.654/11027: 1 lock held by syz.7.654/11028: #0: ffff88805d298118 (&xfs_dir_ilock_class){++++}-{4:4}, at: xfs_ilock_data_map_shared+0x53/0x70 fs/xfs/xfs_inode.c:73 1 lock held by syz.7.654/11029: #0: ffff88805d298118 (&xfs_dir_ilock_class){++++}-{4:4}, at: xfs_ilock_data_map_shared+0x53/0x70 fs/xfs/xfs_inode.c:73 2 locks held by syz.7.654/11030: #0: ffff888031554420 (sb_writers#17){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:556 #1: ffff88805d298330 (&inode->i_sb->s_type->i_mutex_dir_key#2){++++}-{4:4}, at: inode_lock include/linux/fs.h:867 [inline] #1: ffff88805d298330 (&inode->i_sb->s_type->i_mutex_dir_key#2){++++}-{4:4}, at: open_last_lookups fs/namei.c:3797 [inline] #1: ffff88805d298330 (&inode->i_sb->s_type->i_mutex_dir_key#2){++++}-{4:4}, at: path_openat+0x8da/0x3830 fs/namei.c:4036 2 locks held by syz.3.658/11010: #0: ffff88807e6520e0 (&type->s_umount_key#49/1){+.+.}-{4:4}, at: alloc_super+0x204/0x970 fs/super.c:344 #1: ffffffff8dde2e28 (wq_pool_mutex){+.+.}-{4:4}, at: apply_wqattrs_lock kernel/workqueue.c:5179 [inline] #1: ffffffff8dde2e28 (wq_pool_mutex){+.+.}-{4:4}, at: __alloc_workqueue+0x9eb/0x1b70 kernel/workqueue.c:5734 ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.15.0-rc4-syzkaller #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: 10996 Comm: syz.7.654 Not tainted 6.15.0-rc4-syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025 RIP: 0010:preempt_count_add+0xca/0x1a0 kernel/sched/core.c:5864 Code: 8b 34 25 08 e0 71 92 49 81 c6 e0 14 00 00 4c 89 f0 48 c1 e8 03 42 80 3c 38 00 74 08 4c 89 f7 e8 bc d1 8e 00 49 89 1e 5b 41 5e <41> 5f c3 cc cc cc cc cc 89 fb 90 e8 86 34 1d 03 85 c0 74 36 48 c7 RSP: 0018:ffffc9000b92f388 EFLAGS: 00000202 RAX: 0000000000000002 RBX: 00000000000000c0 RCX: ffffffff997d0603 RDX: 0000000000000000 RSI: 00000000000362e9 RDI: 0000000000000001 RBP: ffffc9000b92f6b0 R08: ffffea0000d8ba47 R09: 1ffffd40001b1748 R10: dffffc0000000000 R11: fffff940001b1749 R12: dffffc0000000000 R13: 00000000000362e9 R14: 00000000000362e9 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff888126102000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000555b9b73b9a8 CR3: 0000000061ddc000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: rcu_read_lock_sched include/linux/rcupdate.h:930 [inline] pfn_valid+0xc6/0x420 include/linux/mmzone.h:2117 page_table_check_clear+0x21/0x6e0 mm/page_table_check.c:70 ptep_get_and_clear_full arch/x86/include/asm/jump_label.h:-1 [inline] get_and_clear_full_ptes include/linux/pgtable.h:714 [inline] zap_present_folio_ptes mm/memory.c:1501 [inline] zap_present_ptes mm/memory.c:1586 [inline] do_zap_pte_range mm/memory.c:1687 [inline] zap_pte_range mm/memory.c:1731 [inline] zap_pmd_range mm/memory.c:1823 [inline] zap_pud_range mm/memory.c:1852 [inline] zap_p4d_range mm/memory.c:1873 [inline] unmap_page_range+0x30be/0x4210 mm/memory.c:1894 unmap_vmas+0x25d/0x3c0 mm/memory.c:1984 exit_mmap+0x245/0xba0 mm/mmap.c:1284 __mmput+0x118/0x410 kernel/fork.c:1379 exit_mm+0x1da/0x2c0 kernel/exit.c:589 do_exit+0x859/0x2550 kernel/exit.c:940 do_group_exit+0x21c/0x2d0 kernel/exit.c:1102 get_signal+0x125e/0x1310 kernel/signal.c:3034 arch_do_signal_or_restart+0x95/0x780 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop kernel/entry/common.c:111 [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+0x8b/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: 0033:0x7f948478e969 Code: Unable to access opcode bytes at 0x7f948478e93f. RSP: 002b:00007f9485575038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffea RBX: 00007f94849b5fa0 RCX: 00007f948478e969 RDX: 0000200000000080 RSI: 00002000000000c0 RDI: 0000000000000000 RBP: 00007f9484810ab1 R08: 0000200000000400 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f94849b5fa0 R15: 00007ffee40cf5b8