INFO: task syz.0.17:6554 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.0.17 state:D stack:25608 pid:6554 tgid:6554 ppid:6477 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929 __schedule_loop kernel/sched/core.c:7011 [inline] schedule+0x165/0x360 kernel/sched/core.c:7026 io_schedule+0x80/0xd0 kernel/sched/core.c:7871 folio_wait_bit_common+0x6b0/0xb80 mm/filemap.c:1330 folio_lock include/linux/pagemap.h:1141 [inline] writeback_get_folio mm/page-writeback.c:2468 [inline] writeback_iter+0x8d8/0x12a0 mm/page-writeback.c:2562 iomap_writepages+0x14d/0x2d0 fs/iomap/buffered-io.c:1769 gfs2_writepages+0x177/0x250 fs/gfs2/aops.c:175 do_writepages+0x32e/0x550 mm/page-writeback.c:2604 filemap_fdatawrite_wbc mm/filemap.c:389 [inline] __filemap_fdatawrite_range mm/filemap.c:422 [inline] __filemap_fdatawrite mm/filemap.c:428 [inline] filemap_fdatawrite+0x199/0x240 mm/filemap.c:433 gfs2_ordered_write fs/gfs2/log.c:733 [inline] gfs2_log_flush+0x966/0x24c0 fs/gfs2/log.c:1102 gfs2_trans_end+0x37c/0x570 fs/gfs2/trans.c:158 gfs2_page_mkwrite+0x14a8/0x1910 fs/gfs2/file.c:535 do_page_mkwrite+0x14d/0x310 mm/memory.c:3488 do_shared_fault mm/memory.c:5774 [inline] do_fault mm/memory.c:5836 [inline] do_pte_missing mm/memory.c:4361 [inline] handle_pte_fault mm/memory.c:6177 [inline] __handle_mm_fault+0x1916/0x5400 mm/memory.c:6318 handle_mm_fault+0x40a/0x8e0 mm/memory.c:6487 do_user_addr_fault+0xa7c/0x1380 arch/x86/mm/fault.c:1336 handle_page_fault arch/x86/mm/fault.c:1476 [inline] exc_page_fault+0x82/0x100 arch/x86/mm/fault.c:1532 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 RIP: 0033:0x7f5bfc0550b3 RSP: 002b:00007ffdc9799470 EFLAGS: 00010246 RAX: 0000200000000180 RBX: 0000000000000008 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00005555920153c8 RBP: 00007ffdc9799578 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 00007f5bfc3b5fac R13: 00007f5bfc3b5fa0 R14: fffffffffffffffe R15: 00007ffdc97995c0 Showing all locks held in the system: 1 lock held by khungtaskd/31: #0: ffffffff8dd3d2e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8dd3d2e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #0: ffffffff8dd3d2e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 4 locks held by kworker/u8:4/64: #0: ffff888142ef0948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3238 [inline] #0: ffff888142ef0948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3346 #1: ffffc9000214fba0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3239 [inline] #1: ffffc9000214fba0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3346 #2: ffff88802273a0e0 (&type->s_umount_key#53){.+.+}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:562 #3: ffff88807c05ce50 (&sdp->sd_log_flush_lock){++++}-{4:4}, at: gfs2_log_flush+0x103/0x24c0 fs/gfs2/log.c:1045 2 locks held by getty/5602: #0: ffff88814db100a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000332e2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222 4 locks held by syz.0.17/6554: #0: ffff88805dcfb808 (vm_lock){++++}-{0:0}, at: lock_vma_under_rcu+0x1a3/0x450 mm/mmap_lock.c:238 #1: ffff88802273a518 (sb_pagefaults#2){.+.+}-{0:0}, at: do_page_mkwrite+0x14d/0x310 mm/memory.c:3488 #2: ffff88802273a610 (sb_internal#2){.+.+}-{0:0}, at: gfs2_trans_begin+0x6f/0xe0 fs/gfs2/trans.c:118 #3: ffff88807c05ce50 (&sdp->sd_log_flush_lock){++++}-{4:4}, at: gfs2_log_flush+0x103/0x24c0 fs/gfs2/log.c:1045 1 lock held by gfs2_logd/syz:s/6560: #0: ffff88807c05ce50 (&sdp->sd_log_flush_lock){++++}-{4:4}, at: gfs2_log_flush+0x103/0x24c0 fs/gfs2/log.c:1045 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 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:332 [inline] watchdog+0xf60/0xfa0 kernel/hung_task.c:495 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 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: 7369 Comm: syz.1.211 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 RIP: 0010:check_wait_context kernel/locking/lockdep.c:4878 [inline] RIP: 0010:__lock_acquire+0x4f2/0xd20 kernel/locking/lockdep.c:5187 Code: 4c 8d 3c c7 49 81 c7 50 0b 00 00 eb 1d 44 89 e0 48 ff c3 48 63 8f 28 0b 00 00 49 83 c7 28 41 89 c4 48 39 cb 0f 8d d6 00 00 00 <48> 83 fb 31 0f 83 92 00 00 00 41 8b 07 25 ff 1f 00 00 48 0f a3 05 RSP: 0018:ffffc90003ebef08 EFLAGS: 00000082 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00000000ffffffff RDX: 0000000000000003 RSI: 0000000000000000 RDI: ffff888024895ac0 RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff81737d25 R10: ffffc90003ebf158 R11: ffffffff81ac1c30 R12: ffffffffffffff05 R13: 0000000000000001 R14: ffff888024896640 R15: ffff888024896610 FS: 00007f49dd5fe6c0(0000) GS:ffff88812626c000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f49d5fff000 CR3: 00000000616c2000 CR4: 00000000003526f0 Call Trace: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:867 [inline] class_rcu_constructor include/linux/rcupdate.h:1195 [inline] unwind_next_frame+0xc2/0x2390 arch/x86/kernel/unwind_orc.c:479 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 save_stack+0xf5/0x1f0 mm/page_owner.c:156 __set_page_owner+0x8d/0x4a0 mm/page_owner.c:329 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1850 prep_new_page mm/page_alloc.c:1858 [inline] get_page_from_freelist+0x2365/0x2440 mm/page_alloc.c:3884 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5183 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2416 folio_alloc_mpol_noprof+0x39/0x70 mm/mempolicy.c:2435 shmem_alloc_folio mm/shmem.c:1871 [inline] shmem_alloc_and_add_folio+0x447/0xf60 mm/shmem.c:1910 shmem_get_folio_gfp+0x59d/0x1660 mm/shmem.c:2533 shmem_get_folio mm/shmem.c:2639 [inline] shmem_write_begin+0xf7/0x2b0 mm/shmem.c:3289 generic_perform_write+0x2c5/0x900 mm/filemap.c:4242 shmem_file_write_iter+0xf8/0x120 mm/shmem.c:3464 new_sync_write fs/read_write.c:593 [inline] vfs_write+0x5c9/0xb30 fs/read_write.c:686 ksys_write+0x145/0x250 fs/read_write.c:738 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f49ddf8d69f 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:00007f49dd5fddf0 EFLAGS: 00000293 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000001000000 RCX: 00007f49ddf8d69f RDX: 0000000001000000 RSI: 00007f49d5000000 RDI: 0000000000000003 RBP: 0000000000000000 R08: 0000000000000000 R09: 000000000001f78a R10: 000020000005e5c2 R11: 0000000000000293 R12: 0000000000000003 R13: 00007f49dd5fdef0 R14: 00007f49dd5fdeb0 R15: 00007f49d5000000