INFO: task kworker/u8:8:167 blocked in I/O wait for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u8:8 state:D stack:20552 pid:167 tgid:167 ppid:2 task_flags:0x4248060 flags:0x00080000 Workqueue: writeback wb_workfn (flush-8:0) Call Trace: context_switch kernel/sched/core.c:5583 [inline] __schedule+0x17dd/0x5830 kernel/sched/core.c:7382 __schedule_loop kernel/sched/core.c:7459 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7474 io_schedule+0x7f/0xd0 kernel/sched/core.c:8146 rq_qos_wait+0x266/0x360 block/blk-rq-qos.c:307 __wbt_wait block/blk-wbt.c:598 [inline] wbt_wait+0x326/0x550 block/blk-wbt.c:658 __rq_qos_throttle+0x6b/0xb0 block/blk-rq-qos.c:66 rq_qos_throttle block/blk-rq-qos.h:164 [inline] blk_mq_get_new_requests block/blk-mq.c:3056 [inline] blk_mq_submit_bio+0x1697/0x2c40 block/blk-mq.c:3198 __submit_bio_noacct_mq block/blk-core.c:757 [inline] submit_bio_noacct_nocheck+0x2fe/0xb10 block/blk-core.c:791 blk_crypto_submit_bio include/linux/blk-crypto.h:212 [inline] ext4_io_submit fs/ext4/page-io.c:399 [inline] io_submit_add_bh fs/ext4/page-io.c:455 [inline] ext4_bio_write_folio+0x101a/0x18c0 fs/ext4/page-io.c:550 mpage_process_page_bufs+0x6bd/0x8a0 fs/ext4/inode.c:2327 mpage_prepare_extent_to_map+0xf8d/0x1880 fs/ext4/inode.c:2875 ext4_do_writepages+0xc08/0x44a0 fs/ext4/inode.c:3023 ext4_writepages+0x1fe/0x4e0 fs/ext4/inode.c:3171 do_writepages+0x338/0x560 mm/page-writeback.c:2562 __writeback_single_inode+0x136/0x1220 fs/fs-writeback.c:1809 writeback_sb_inodes+0x9de/0x1af0 fs/fs-writeback.c:2120 __writeback_inodes_wb+0x114/0x250 fs/fs-writeback.c:2196 wb_writeback+0x42f/0xad0 fs/fs-writeback.c:2307 wb_check_old_data_flush fs/fs-writeback.c:2411 [inline] wb_do_writeback fs/fs-writeback.c:2490 [inline] wb_workfn+0xc92/0x10f0 fs/fs-writeback.c:2518 process_one_work kernel/workqueue.c:3495 [inline] process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3578 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3659 kthread+0x38b/0x480 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 INFO: task jbd2/sda1-8:4968 blocked in I/O wait for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:jbd2/sda1-8 state:D stack:25992 pid:4968 tgid:4968 ppid:2 task_flags:0x240040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5583 [inline] __schedule+0x17dd/0x5830 kernel/sched/core.c:7382 __schedule_loop kernel/sched/core.c:7459 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7474 io_schedule+0x7f/0xd0 kernel/sched/core.c:8146 bit_wait_io+0x13/0x110 kernel/sched/wait_bit.c:258 __wait_on_bit+0xac/0x300 kernel/sched/wait_bit.c:52 out_of_line_wait_on_bit+0x13b/0x190 kernel/sched/wait_bit.c:67 wait_on_buffer include/linux/buffer_head.h:476 [inline] jbd2_journal_commit_transaction+0x2f6e/0x5c80 fs/jbd2/commit.c:834 kjournald2+0x3bc/0x740 fs/jbd2/journal.c:200 kthread+0x38b/0x480 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 INFO: task syz-executor:5627 blocked in I/O wait for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:21000 pid:5627 tgid:5627 ppid:5626 task_flags:0x440100 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5583 [inline] __schedule+0x17dd/0x5830 kernel/sched/core.c:7382 __schedule_loop kernel/sched/core.c:7459 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7474 io_schedule+0x7f/0xd0 kernel/sched/core.c:8146 bit_wait_io+0x13/0x110 kernel/sched/wait_bit.c:258 __wait_on_bit+0xac/0x300 kernel/sched/wait_bit.c:52 out_of_line_wait_on_bit+0x13b/0x190 kernel/sched/wait_bit.c:67 wait_on_bit_io include/linux/wait_bit.h:106 [inline] do_get_write_access+0x658/0x10c0 fs/jbd2/transaction.c:1113 jbd2_journal_get_write_access+0x1d7/0x230 fs/jbd2/transaction.c:1263 __ext4_journal_get_write_access+0xec/0x620 fs/ext4/ext4_jbd2.c:253 ext4_reserve_inode_write+0x294/0x360 fs/ext4/inode.c:7451 __ext4_mark_inode_dirty+0x141/0x7e0 fs/ext4/inode.c:7642 ext4_dirty_inode+0xd0/0x110 fs/ext4/inode.c:7679 __mark_inode_dirty+0x3a8/0x13b0 fs/fs-writeback.c:2751 generic_update_time fs/inode.c:2264 [inline] file_update_time_flags+0x399/0x440 fs/inode.c:2494 ext4_page_mkwrite+0x21f/0x1470 fs/ext4/inode.c:7864 do_page_mkwrite+0x147/0x310 mm/memory.c:3884 wp_page_shared mm/memory.c:4288 [inline] do_wp_page+0x1a85/0x4b80 mm/memory.c:4511 handle_pte_fault mm/memory.c:6684 [inline] __handle_mm_fault mm/memory.c:6809 [inline] handle_mm_fault+0x19c9/0x2f80 mm/memory.c:6976 do_user_addr_fault+0xb35/0x1480 arch/x86/mm/fault.c:1343 handle_page_fault arch/x86/mm/fault.c:1483 [inline] exc_page_fault+0x6a/0xc0 arch/x86/mm/fault.c:1536 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:595 RIP: 0033:0x7f9b1236e687 RSP: 002b:00007ffd438765b8 EFLAGS: 00010206 RAX: 00007f9b0fe00000 RBX: 00005555759225f0 RCX: 0000000000002639 RDX: 0000000000004639 RSI: 000055557598d110 RDI: 00007f9b0fe02000 RBP: 00007ffd438765d0 R08: 00007f9b0fe00000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000555575914720 R13: 000000000000000d R14: 0000000000000001 R15: 0000000000000000 INFO: task syz.5.387:7019 blocked in I/O wait for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.5.387 state:D stack:25608 pid:7019 tgid:7019 ppid:6028 task_flags:0x440040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5583 [inline] __schedule+0x17dd/0x5830 kernel/sched/core.c:7382 __schedule_loop kernel/sched/core.c:7459 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7474 io_schedule+0x7f/0xd0 kernel/sched/core.c:8146 bit_wait_io+0x13/0x110 kernel/sched/wait_bit.c:258 __wait_on_bit+0xac/0x300 kernel/sched/wait_bit.c:52 out_of_line_wait_on_bit+0x13b/0x190 kernel/sched/wait_bit.c:67 wait_on_bit_io include/linux/wait_bit.h:106 [inline] do_get_write_access+0x658/0x10c0 fs/jbd2/transaction.c:1113 jbd2_journal_get_write_access+0x1d7/0x230 fs/jbd2/transaction.c:1263 __ext4_journal_get_write_access+0xec/0x620 fs/ext4/ext4_jbd2.c:253 ext4_reserve_inode_write+0x294/0x360 fs/ext4/inode.c:7451 __ext4_mark_inode_dirty+0x141/0x7e0 fs/ext4/inode.c:7642 ext4_dirty_inode+0xd0/0x110 fs/ext4/inode.c:7679 __mark_inode_dirty+0x3a8/0x13b0 fs/fs-writeback.c:2751 generic_update_time fs/inode.c:2264 [inline] file_update_time_flags+0x399/0x440 fs/inode.c:2494 ext4_page_mkwrite+0x21f/0x1470 fs/ext4/inode.c:7864 do_page_mkwrite+0x147/0x310 mm/memory.c:3884 do_shared_fault mm/memory.c:6180 [inline] do_fault mm/memory.c:6242 [inline] do_pte_missing+0x70f/0x3570 mm/memory.c:4771 handle_pte_fault mm/memory.c:6657 [inline] __handle_mm_fault mm/memory.c:6809 [inline] handle_mm_fault+0x1807/0x2f80 mm/memory.c:6976 do_user_addr_fault+0xb35/0x1480 arch/x86/mm/fault.c:1343 handle_page_fault arch/x86/mm/fault.c:1483 [inline] exc_page_fault+0x6a/0xc0 arch/x86/mm/fault.c:1536 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:595 RIP: 0033:0x7fd138474332 RSP: 002b:00007ffde79965b0 EFLAGS: 00010202 RAX: 0000000000002008 RBX: 00007fd139355720 RCX: 0000000000000000 RDX: 0000001b34c22000 RSI: 0000000000000008 RDI: 00007fd139355720 RBP: 0000000000000078 R08: 00007fd138810000 R09: 00007fd138826038 R10: 0000000000000001 R11: 0000000000000002 R12: ffffffff817023c1 R13: 00007fd138826038 R14: 0000000000000076 R15: ffffffffffffe000 INFO: task syz.1.389:7025 blocked in I/O wait for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.1.389 state:D stack:26936 pid:7025 tgid:7025 ppid:5639 task_flags:0x440040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5583 [inline] __schedule+0x17dd/0x5830 kernel/sched/core.c:7382 __schedule_loop kernel/sched/core.c:7459 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7474 io_schedule+0x7f/0xd0 kernel/sched/core.c:8146 bit_wait_io+0x13/0x110 kernel/sched/wait_bit.c:258 __wait_on_bit+0xac/0x300 kernel/sched/wait_bit.c:52 out_of_line_wait_on_bit+0x13b/0x190 kernel/sched/wait_bit.c:67 wait_on_bit_io include/linux/wait_bit.h:106 [inline] do_get_write_access+0x658/0x10c0 fs/jbd2/transaction.c:1113 jbd2_journal_get_write_access+0x1d7/0x230 fs/jbd2/transaction.c:1263 __ext4_journal_get_write_access+0xec/0x620 fs/ext4/ext4_jbd2.c:253 ext4_reserve_inode_write+0x294/0x360 fs/ext4/inode.c:7451 __ext4_mark_inode_dirty+0x141/0x7e0 fs/ext4/inode.c:7642 ext4_dirty_inode+0xd0/0x110 fs/ext4/inode.c:7679 __mark_inode_dirty+0x3a8/0x13b0 fs/fs-writeback.c:2751 generic_update_time fs/inode.c:2264 [inline] touch_atime+0x568/0x670 fs/inode.c:2339 file_accessed include/linux/fs.h:2283 [inline] ext4_file_mmap_prepare+0x277/0x450 fs/ext4/file.c:919 vfs_mmap_prepare include/linux/fs.h:2075 [inline] call_mmap_prepare mm/vma.c:2947 [inline] __mmap_region mm/vma.c:3064 [inline] mmap_region+0xef9/0x2840 mm/vma.c:3162 do_mmap+0xe0a/0x1300 mm/mmap.c:573 vm_mmap_pgoff+0x27a/0x520 mm/util.c:581 ksys_mmap_pgoff+0x4dc/0x760 mm/mmap.c:619 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f7bd4f9f2c2 RSP: 002b:00007fff1a5b3858 EFLAGS: 00000206 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 0000001b2cd64000 RCX: 00007f7bd4f9f2c2 RDX: 0000000000000003 RSI: 00000000005c0000 RDI: 0000001b2cd64000 RBP: 0000000000100001 R08: 0000000000000004 R09: 0000000000040000 R10: 0000000000100001 R11: 0000000000000206 R12: 000000000000005d R13: 00000000000927c0 R14: 000000000001f8da R15: 00007fff1a5b3b30 INFO: task syz.4.385:7026 blocked in I/O wait for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.4.385 state:D stack:26936 pid:7026 tgid:7026 ppid:5637 task_flags:0x440040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5583 [inline] __schedule+0x17dd/0x5830 kernel/sched/core.c:7382 __schedule_loop kernel/sched/core.c:7459 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7474 io_schedule+0x7f/0xd0 kernel/sched/core.c:8146 bit_wait_io+0x13/0x110 kernel/sched/wait_bit.c:258 __wait_on_bit+0xac/0x300 kernel/sched/wait_bit.c:52 out_of_line_wait_on_bit+0x13b/0x190 kernel/sched/wait_bit.c:67 wait_on_bit_io include/linux/wait_bit.h:106 [inline] do_get_write_access+0x658/0x10c0 fs/jbd2/transaction.c:1113 jbd2_journal_get_write_access+0x1d7/0x230 fs/jbd2/transaction.c:1263 __ext4_journal_get_write_access+0xec/0x620 fs/ext4/ext4_jbd2.c:253 ext4_reserve_inode_write+0x294/0x360 fs/ext4/inode.c:7451 __ext4_mark_inode_dirty+0x141/0x7e0 fs/ext4/inode.c:7642 ext4_dirty_inode+0xd0/0x110 fs/ext4/inode.c:7679 __mark_inode_dirty+0x3a8/0x13b0 fs/fs-writeback.c:2751 generic_update_time fs/inode.c:2264 [inline] touch_atime+0x568/0x670 fs/inode.c:2339 file_accessed include/linux/fs.h:2283 [inline] ext4_file_mmap_prepare+0x277/0x450 fs/ext4/file.c:919 vfs_mmap_prepare include/linux/fs.h:2075 [inline] call_mmap_prepare mm/vma.c:2947 [inline] __mmap_region mm/vma.c:3064 [inline] mmap_region+0xef9/0x2840 mm/vma.c:3162 do_mmap+0xe0a/0x1300 mm/mmap.c:573 vm_mmap_pgoff+0x27a/0x520 mm/util.c:581 ksys_mmap_pgoff+0x4dc/0x760 mm/mmap.c:619 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fdb2d59f2c2 RSP: 002b:00007ffe625ef378 EFLAGS: 00000206 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 0000001b2d064000 RCX: 00007fdb2d59f2c2 RDX: 0000000000000003 RSI: 00000000005c0000 RDI: 0000001b2d064000 RBP: 0000000000100001 R08: 0000000000000004 R09: 0000000000040000 R10: 0000000000100001 R11: 0000000000000206 R12: 0000000000000057 R13: 00000000000927c0 R14: 000000000001f796 R15: 00007ffe625ef650 Showing all locks held in the system: locks held by pr/ttyS0/35: 2, last CPU#1: #0: ffffffff90033f18 (console_srcu){....}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:314 [inline] #0: ffffffff90033f18 (console_srcu){....}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:493 [inline] #0: ffffffff90033f18 (console_srcu){....}-{0:0}, at: console_srcu_read_lock+0x30/0x60 kernel/printk/printk.c:291 #1: ffffffff9c203ef8 (&port_lock_key){-.-.}-{3:3}, at: __uart_port_lock_irqsave include/linux/serial_core.h:613 [inline] #1: ffffffff9c203ef8 (&port_lock_key){-.-.}-{3:3}, at: univ8250_console_device_lock+0x67/0xc0 drivers/tty/serial/8250/8250_core.c:413 locks held by khungtaskd/36: 1, last CPU#0: #0: ffffffff9015a420 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline] #0: ffffffff9015a420 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #0: ffffffff9015a420 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6871 locks held by kworker/u8:8/167: 4, on CPU#1: #0: ffff888021ae3948 ((wq_completion)writeback){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline] #0: ffff888021ae3948 ((wq_completion)writeback){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #0: ffff888021ae3948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3460 [inline] #0: ffff888021ae3948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3578 #1: ffffc90003007c40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline] #1: ffffc90003007c40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #1: ffffc90003007c40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3460 [inline] #1: ffffc90003007c40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3578 #2: ffff88807ffb6100 (&type->s_umount_key#35){++++}-{4:4}, at: super_trylock_shared+0x23/0xf0 fs/super.c:642 #3: ffff88807ff94cd8 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_writepages+0x1f1/0x4e0 fs/ext4/inode.c:3170 locks held by getty/5395: 2, on CPU#0: #0: ffff888036f420a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000322e2e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360 drivers/tty/n_tty.c:2211 locks held by syz-executor/5627: 3, on CPU#0: #0: ffff88807789f308 (vm_lock){++++}-{0:0}, at: lock_vma_under_rcu+0x1d1/0x500 mm/mmap_lock.c:339 #1: ffff88807ffb6570 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs/super.h:159 [inline] #1: ffff88807ffb6570 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x1fe/0x1470 fs/ext4/inode.c:7863 #2: ffff88807fe4c950 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x1fb0/0x21f0 fs/jbd2/transaction.c:444 locks held by syz.5.387/7019: 3, on CPU#0: #0: ffff888056b38308 (vm_lock){++++}-{0:0}, at: lock_vma_under_rcu+0x1d1/0x500 mm/mmap_lock.c:339 #1: ffff88807ffb6570 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs/super.h:159 [inline] #1: ffff88807ffb6570 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x1fe/0x1470 fs/ext4/inode.c:7863 #2: ffff88807fe4c950 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x1fb0/0x21f0 fs/jbd2/transaction.c:444 locks held by syz.1.389/7025: 3, on CPU#1: #0: ffff88807ef04cc0 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:566 [inline] #0: ffff88807ef04cc0 (&mm->mmap_lock){++++}-{4:4}, at: vm_mmap_pgoff+0x1ed/0x520 mm/util.c:579 #1: ffff88807ffb6478 (sb_writers#4){.+.+}-{0:0}, at: file_accessed include/linux/fs.h:2283 [inline] #1: ffff88807ffb6478 (sb_writers#4){.+.+}-{0:0}, at: ext4_file_mmap_prepare+0x277/0x450 fs/ext4/file.c:919 #2: ffff88807fe4c950 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x1fb0/0x21f0 fs/jbd2/transaction.c:444 locks held by syz.4.385/7026: 3, on CPU#1: #0: ffff88813fe36540 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:566 [inline] #0: ffff88813fe36540 (&mm->mmap_lock){++++}-{4:4}, at: vm_mmap_pgoff+0x1ed/0x520 mm/util.c:579 #1: ffff88807ffb6478 (sb_writers#4){.+.+}-{0:0}, at: file_accessed include/linux/fs.h:2283 [inline] #1: ffff88807ffb6478 (sb_writers#4){.+.+}-{0:0}, at: ext4_file_mmap_prepare+0x277/0x450 fs/ext4/file.c:919 #2: ffff88807fe4c950 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x1fb0/0x21f0 fs/jbd2/transaction.c:444 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 36 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/15/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:123 nmi_trigger_cpumask_backtrace+0x17d/0x390 lib/nmi_backtrace.c:66 trigger_all_cpu_backtrace include/linux/nmi.h:164 [inline] __sys_info lib/sys_info.c:157 [inline] sys_info+0x135/0x170 lib/sys_info.c:165 check_hung_uninterruptible_tasks kernel/hung_task.c:377 [inline] watchdog+0x1073/0x10f0 kernel/hung_task.c:598 kthread+0x38b/0x480 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 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: 4994 Comm: klogd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/15/2026 RIP: 0010:get_current arch/x86/include/asm/current.h:25 [inline] RIP: 0010:lockdep_enabled kernel/locking/lockdep.c:124 [inline] RIP: 0010:lock_is_held_type+0x2f/0x150 kernel/locking/lockdep.c:6009 Code: 41 57 41 56 41 55 41 54 53 bb ff ff ff ff 83 3d 96 61 b9 05 00 0f 84 e4 00 00 00 65 8b 05 51 cf dc 08 85 c0 0f 85 d5 00 00 00 <65> 4c 8b 2d 91 87 dc 08 41 83 bd a4 0b 00 00 00 0f 85 bf 00 00 00 RSP: 0018:ffffc90002fd7528 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 00000000ffffffff RCX: 8000000000000001 RDX: 0000000000000000 RSI: 00000000ffffffff RDI: ffffffff9015a420 RBP: 0000000000000003 R08: ffffffff824c2ddc R09: 0000000000000000 R10: dffffc0000000000 R11: ffffed100aa76296 R12: 0000000000044718 R13: dffffc0000000000 R14: ffff88813ff70118 R15: 0000000000001000 FS: 00007fc3b650fc80(0000) GS:ffff88812350b000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000555c7fba9168 CR3: 000000007ea74000 CR4: 00000000003526f0 Call Trace: lookup_page_ext mm/page_ext.c:253 [inline] page_ext_lookup+0xe7/0x180 mm/page_ext.c:504 page_ext_iter_begin include/linux/page_ext.h:136 [inline] __page_table_check_zero+0x16b/0x430 mm/page_table_check.c:139 page_table_check_free include/linux/page_table_check.h:46 [inline] __free_pages_prepare mm/page_alloc.c:1404 [inline] __free_frozen_pages+0xca7/0xd90 mm/page_alloc.c:2957 __slab_free+0x269/0x2c0 mm/slub.c:5926 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x99/0x100 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:361 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4720 [inline] slab_alloc_node mm/slub.c:5033 [inline] __do_kmalloc_node mm/slub.c:5530 [inline] __kmalloc_node_track_caller_noprof+0x446/0x720 mm/slub.c:5662 kmalloc_reserve net/core/skbuff.c:638 [inline] __alloc_skb+0x2c1/0x7a0 net/core/skbuff.c:716 alloc_skb include/linux/skbuff.h:1390 [inline] alloc_skb_with_frags+0xc6/0x760 net/core/skbuff.c:6898 sock_alloc_send_pskb+0xc69/0xd90 net/core/sock.c:3093 unix_dgram_sendmsg+0x4ff/0x17e0 net/unix/af_unix.c:2148 sock_sendmsg_nosec+0x14e/0x190 net/socket.c:800 __sock_sendmsg net/socket.c:818 [inline] __sys_sendto+0x408/0x5a0 net/socket.c:2283 __do_sys_sendto net/socket.c:2290 [inline] __se_sys_sendto net/socket.c:2286 [inline] __x64_sys_sendto+0xde/0x100 net/socket.c:2286 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fc3b665f407 Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff RSP: 002b:00007ffec88c8f90 EFLAGS: 00000202 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007fc3b650fc80 RCX: 00007fc3b665f407 RDX: 000000000000007c RSI: 00007ffec88c90d0 RDI: 0000000000000003 RBP: 00007ffec88c9500 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000004000 R11: 0000000000000202 R12: 00007ffec88c9518 R13: 00007ffec88c90d0 R14: 0000000000000061 R15: 00007ffec88c90d0