INFO: task kworker/u8:8:1165 blocked in I/O wait for more than 143 seconds. Tainted: G L syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u8:8 state:D stack:21768 pid:1165 tgid:1165 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 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_mb_mark_context+0x171/0xec0 fs/ext4/mballoc.c:4110 ext4_mb_mark_diskspace_used+0x338/0x760 fs/ext4/mballoc.c:4239 ext4_mb_new_blocks+0x1062/0x4520 fs/ext4/mballoc.c:6327 ext4_ext_map_blocks+0x1427/0x5480 fs/ext4/extents.c:4469 ext4_map_create_blocks+0x116/0x530 fs/ext4/inode.c:697 ext4_map_blocks+0xe8e/0x1c60 fs/ext4/inode.c:942 mpage_map_one_extent fs/ext4/inode.c:2505 [inline] mpage_map_and_submit_extent fs/ext4/inode.c:2601 [inline] ext4_do_writepages+0x1978/0x44a0 fs/ext4/inode.c:3077 ext4_writepages+0x1fe/0x4e0 fs/ext4/inode.c:3171 do_writepages+0x338/0x560 mm/page-writeback.c:2560 __writeback_single_inode+0x136/0x1220 fs/fs-writeback.c:1800 writeback_sb_inodes+0x9de/0x1af0 fs/fs-writeback.c:2111 __writeback_inodes_wb+0x114/0x240 fs/fs-writeback.c:2187 wb_writeback+0x42f/0xad0 fs/fs-writeback.c:2298 wb_check_old_data_flush fs/fs-writeback.c:2402 [inline] wb_do_writeback fs/fs-writeback.c:2481 [inline] wb_workfn+0xc92/0x10f0 fs/fs-writeback.c:2509 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/sda1-8:4939 blocked in I/O wait for more than 143 seconds. Tainted: G L syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:jbd2/sda1-8 state:D stack:25768 pid:4939 tgid:4939 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:5597 blocked in I/O wait for more than 143 seconds. Tainted: G L syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:22600 pid:5597 tgid:5597 ppid:5596 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:7445 __ext4_mark_inode_dirty+0x141/0x7e0 fs/ext4/inode.c:7636 ext4_dirty_inode+0xd0/0x110 fs/ext4/inode.c:7673 __mark_inode_dirty+0x3a8/0x13b0 fs/fs-writeback.c:2741 generic_update_time fs/inode.c:2253 [inline] file_update_time_flags+0x399/0x440 fs/inode.c:2483 ext4_page_mkwrite+0x21f/0x1470 fs/ext4/inode.c:7858 do_page_mkwrite+0x147/0x310 mm/memory.c:3878 wp_page_shared mm/memory.c:4279 [inline] do_wp_page+0x1a85/0x4b60 mm/memory.c:4502 handle_pte_fault mm/memory.c:6672 [inline] __handle_mm_fault mm/memory.c:6797 [inline] handle_mm_fault+0x15c1/0x3540 mm/memory.c:6964 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: 0033:0x7f926407dad6 RSP: 002b:00007ffd8c899530 EFLAGS: 00010202 RAX: 00007f9262190000 RBX: 0000555595238390 RCX: 0000000000000003 RDX: 00000000000034b6 RSI: 000055559523a2a8 RDI: 0000000000000008 RBP: 00007ffd8c899a30 R08: 000055559523a2b8 R09: 00000000000000a4 R10: 00007f92643f9e20 R11: 0000000000000000 R12: 00007ffd8c899870 R13: 00007ffd8c899660 R14: 585858582e7a7973 R15: 00007ffd8c8995b0 INFO: task syz-executor:8375 blocked in I/O wait for more than 143 seconds. Tainted: G L syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:22216 pid:8375 tgid:8375 ppid:8360 task_flags:0x400140 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] __ext4_find_entry+0xfb4/0x1930 fs/ext4/namei.c:1613 ext4_lookup_entry fs/ext4/namei.c:1705 [inline] ext4_lookup+0x17b/0x710 fs/ext4/namei.c:1771 lookup_one_qstr_excl+0x12d/0x360 fs/namei.c:1810 __start_dirop fs/namei.c:2920 [inline] start_dirop fs/namei.c:2942 [inline] filename_create+0x20e/0x370 fs/namei.c:5102 filename_mkdirat+0xd2/0x510 fs/namei.c:5448 __do_sys_mkdirat fs/namei.c:5476 [inline] __se_sys_mkdirat+0x35/0x150 fs/namei.c:5473 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: 0033:0x7f73d819e3c7 RSP: 002b:00007ffedce9cdf8 EFLAGS: 00000206 ORIG_RAX: 0000000000000102 RAX: ffffffffffffffda RBX: 00007f73d8236564 RCX: 00007f73d819e3c7 RDX: 00000000000001ff RSI: 00007f73d8236564 RDI: 00000000ffffff9c RBP: 00007f73d84267b8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000008 R13: 0000000000000003 R14: 00007ffedce9d068 R15: 0000000000000000 INFO: task syz.2.1003:8527 blocked in I/O wait for more than 143 seconds. Tainted: G L syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.2.1003 state:D stack:25576 pid:8527 tgid:8527 ppid:5623 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:7445 __ext4_mark_inode_dirty+0x141/0x7e0 fs/ext4/inode.c:7636 ext4_dirty_inode+0xd0/0x110 fs/ext4/inode.c:7673 __mark_inode_dirty+0x3a8/0x13b0 fs/fs-writeback.c:2741 generic_update_time fs/inode.c:2253 [inline] file_update_time_flags+0x399/0x440 fs/inode.c:2483 ext4_page_mkwrite+0x21f/0x1470 fs/ext4/inode.c:7858 do_page_mkwrite+0x147/0x310 mm/memory.c:3878 do_shared_fault mm/memory.c:6171 [inline] do_fault mm/memory.c:6233 [inline] do_pte_missing+0x70f/0x3570 mm/memory.c:4762 handle_pte_fault mm/memory.c:6648 [inline] __handle_mm_fault mm/memory.c:6797 [inline] handle_mm_fault+0x1a2a/0x3540 mm/memory.c:6964 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: 0033:0x7fd2c3873ba9 RSP: 002b:00007ffc0fcd4f70 EFLAGS: 00010202 RAX: 0000001b33724000 RBX: ffffffff825eb14a RCX: 0000001b33723ff8 RDX: 00000000005ffde8 RSI: 00000000005ffde8 RDI: 00007fd2c4755700 RBP: 0000000000000001 R08: 0000000000000000 R09: 00007fd2c3c12000 R10: 00007fd2c4755700 R11: 0000000000000000 R12: 00007fd2c3c26038 R13: 0000000000000000 R14: ffffffff825eb820 R15: 00007fd2c4755720 INFO: task syz.4.1008:8536 blocked in I/O wait for more than 143 seconds. Tainted: G L syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.4.1008 state:D stack:24472 pid:8536 tgid:8536 ppid:5618 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:7445 __ext4_mark_inode_dirty+0x141/0x7e0 fs/ext4/inode.c:7636 ext4_dirty_inode+0xd0/0x110 fs/ext4/inode.c:7673 __mark_inode_dirty+0x3a8/0x13b0 fs/fs-writeback.c:2741 generic_update_time fs/inode.c:2253 [inline] file_update_time_flags+0x399/0x440 fs/inode.c:2483 ext4_page_mkwrite+0x21f/0x1470 fs/ext4/inode.c:7858 do_page_mkwrite+0x147/0x310 mm/memory.c:3878 do_shared_fault mm/memory.c:6171 [inline] do_fault mm/memory.c:6233 [inline] do_pte_missing+0x70f/0x3570 mm/memory.c:4762 handle_pte_fault mm/memory.c:6648 [inline] __handle_mm_fault mm/memory.c:6797 [inline] handle_mm_fault+0x1a2a/0x3540 mm/memory.c:6964 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: 0033:0x7ff795c74332 RSP: 002b:00007ffc49205e30 EFLAGS: 00010202 RAX: 0000000000005008 RBX: 00007ff796b55720 RCX: 0000000000000000 RDX: 0000001b3391f000 RSI: 0000000000000008 RDI: 00007ff796b55720 RBP: 00000000000007b9 R08: 00007ff796010000 R09: 00007ff796026038 R10: 0000000000000001 R11: 0000000000000001 R12: ffffffff89bc93d2 R13: 00007ff796026038 R14: 0000000000000159 R15: ffffffffffffb000 INFO: task syz.1.1011:8547 blocked in I/O wait for more than 143 seconds. Tainted: G L syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.1.1011 state:D stack:25576 pid:8547 tgid:8547 ppid:5613 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:7445 __ext4_mark_inode_dirty+0x141/0x7e0 fs/ext4/inode.c:7636 ext4_dirty_inode+0xd0/0x110 fs/ext4/inode.c:7673 __mark_inode_dirty+0x3a8/0x13b0 fs/fs-writeback.c:2741 generic_update_time fs/inode.c:2253 [inline] file_update_time_flags+0x399/0x440 fs/inode.c:2483 ext4_page_mkwrite+0x21f/0x1470 fs/ext4/inode.c:7858 do_page_mkwrite+0x147/0x310 mm/memory.c:3878 do_shared_fault mm/memory.c:6171 [inline] do_fault mm/memory.c:6233 [inline] do_pte_missing+0x70f/0x3570 mm/memory.c:4762 handle_pte_fault mm/memory.c:6648 [inline] __handle_mm_fault mm/memory.c:6797 [inline] handle_mm_fault+0x1a2a/0x3540 mm/memory.c:6964 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: 0033:0x7f8c23873c09 RSP: 002b:00007fff1457b510 EFLAGS: 00010202 RAX: 0000001b33624000 RBX: 0000000000000000 RCX: 00000000005ffde8 RDX: 0000001b33623ffc RSI: 00000000005ffde8 RDI: 00007f8c24755700 RBP: 0000000000000000 R08: 0000000000000000 R09: 00007f8c23c12000 R10: 00007f8c24755700 R11: 0000000000000000 R12: 0000000000000000 R13: 000000000000000b R14: ffffffff816dc0ce R15: 00007f8c24755720 INFO: task syz.0.1010:8551 blocked in I/O wait for more than 143 seconds. Tainted: G L syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.0.1010 state:D stack:26184 pid:8551 tgid:8551 ppid:6047 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:7445 __ext4_mark_inode_dirty+0x141/0x7e0 fs/ext4/inode.c:7636 ext4_dirty_inode+0xd0/0x110 fs/ext4/inode.c:7673 __mark_inode_dirty+0x3a8/0x13b0 fs/fs-writeback.c:2741 generic_update_time fs/inode.c:2253 [inline] touch_atime+0x568/0x670 fs/inode.c:2328 file_accessed include/linux/fs.h:2281 [inline] ext4_file_mmap_prepare+0x277/0x450 fs/ext4/file.c:919 vfs_mmap_prepare include/linux/fs.h:2073 [inline] call_mmap_prepare mm/vma.c:2921 [inline] __mmap_region mm/vma.c:3038 [inline] mmap_region+0xef9/0x2840 mm/vma.c:3136 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: 0033:0x7fe73799f2c2 RSP: 002b:00007ffd7c4687f8 EFLAGS: 00000206 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 0000001b2df64000 RCX: 00007fe73799f2c2 RDX: 0000000000000003 RSI: 00000000005c0000 RDI: 0000001b2df64000 RBP: 0000000000100001 R08: 0000000000000004 R09: 0000000000040000 R10: 0000000000100001 R11: 0000000000000206 R12: 00000000000000b3 R13: 00000000000927c0 R14: 0000000000033caf R15: 00007ffd7c468ad0 Showing all locks held in the system: locks held by pr/ttyS0/33: 2, last CPU#1: #0: ffffffff8fc33f58 (console_srcu){....}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:314 [inline] #0: ffffffff8fc33f58 (console_srcu){....}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:493 [inline] #0: ffffffff8fc33f58 (console_srcu){....}-{0:0}, at: console_srcu_read_lock+0x30/0x60 kernel/printk/printk.c:291 #1: ffff8880b853c360 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2d/0x160 kernel/sched/core.c:677 locks held by khungtaskd/34: 1, last CPU#0: #0: ffffffff8fd5a4a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline] #0: ffffffff8fd5a4a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #0: ffffffff8fd5a4a0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6871 locks held by kworker/u8:8/1165: 6, on CPU#1: #0: ffff8880212c6148 ((wq_completion)writeback){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline] #0: ffff8880212c6148 ((wq_completion)writeback){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #0: ffff8880212c6148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3460 [inline] #0: ffff8880212c6148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3578 #1: ffffc90004ddfc40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline] #1: ffffc90004ddfc40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #1: ffffc90004ddfc40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3460 [inline] #1: ffffc90004ddfc40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3578 #2: ffff8880373da0e8 (&type->s_umount_key#35){++++}-{4:4}, at: super_trylock_shared+0x23/0xf0 fs/super.c:670 #3: ffff8880373c4cd8 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_writepages+0x1f1/0x4e0 fs/ext4/inode.c:3170 #4: ffff8880373d8950 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x1fb0/0x21f0 fs/jbd2/transaction.c:444 #5: ffff8880771ddcb8 (&ei->i_data_sem#2){++++}-{4:4}, at: ext4_map_blocks+0xacb/0x1c60 fs/ext4/inode.c:926 locks held by klogd/4965: 2, last CPU#1: #0: ffffffff8feb1a70 (remove_cache_srcu){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:213 [inline] #0: ffffffff8feb1a70 (remove_cache_srcu){.+.+}-{0:0}, at: srcu_read_lock+0x27/0x60 include/linux/srcu.h:320 #1: ffffffff9bd41bf0 (&obj_hash[i].lock){-.-.}-{2:2}, at: __debug_check_no_obj_freed lib/debugobjects.c:1160 [inline] #1: ffffffff9bd41bf0 (&obj_hash[i].lock){-.-.}-{2:2}, at: debug_check_no_obj_freed+0xcb/0x450 lib/debugobjects.c:1201 locks held by getty/5365: 2, on CPU#0: #0: ffff8880373830a0 (&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/5597: 3, on CPU#1: #0: ffff888035db46c8 (vm_lock){++++}-{0:0}, at: lock_vma_under_rcu+0x1d1/0x500 mm/mmap_lock.c:337 #1: ffff8880373da558 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs/super.h:159 [inline] #1: ffff8880373da558 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x1fe/0x1470 fs/ext4/inode.c:7857 #2: ffff8880373d8950 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x1fb0/0x21f0 fs/jbd2/transaction.c:444 locks held by syz-executor/8375: 2, on CPU#1: #0: ffff8880373da460 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:531 #1: ffff8880772f9eb0 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1069 [inline] #1: ffff8880772f9eb0 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: __start_dirop fs/namei.c:2918 [inline] #1: ffff8880772f9eb0 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: start_dirop fs/namei.c:2942 [inline] #1: ffff8880772f9eb0 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: filename_create+0x200/0x370 fs/namei.c:5102 locks held by syz.2.1003/8527: 3, on CPU#0: #0: ffff8880246ade48 (vm_lock){++++}-{0:0}, at: lock_vma_under_rcu+0x1d1/0x500 mm/mmap_lock.c:337 #1: ffff8880373da558 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs/super.h:159 [inline] #1: ffff8880373da558 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x1fe/0x1470 fs/ext4/inode.c:7857 #2: ffff8880373d8950 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x1fb0/0x21f0 fs/jbd2/transaction.c:444 locks held by syz.4.1008/8536: 3, on CPU#1: #0: ffff888033eeebc8 (vm_lock){++++}-{0:0}, at: lock_vma_under_rcu+0x1d1/0x500 mm/mmap_lock.c:337 #1: ffff8880373da558 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs/super.h:159 [inline] #1: ffff8880373da558 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x1fe/0x1470 fs/ext4/inode.c:7857 #2: ffff8880373d8950 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x1fb0/0x21f0 fs/jbd2/transaction.c:444 locks held by syz.1.1011/8547: 3, on CPU#0: #0: ffff888035321948 (vm_lock){++++}-{0:0}, at: lock_vma_under_rcu+0x1d1/0x500 mm/mmap_lock.c:337 #1: ffff8880373da558 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs/super.h:159 [inline] #1: ffff8880373da558 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x1fe/0x1470 fs/ext4/inode.c:7857 #2: ffff8880373d8950 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x1fb0/0x21f0 fs/jbd2/transaction.c:444 locks held by syz.0.1010/8551: 3, on CPU#0: #0: ffff88807f7f2800 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:550 [inline] #0: ffff88807f7f2800 (&mm->mmap_lock){++++}-{4:4}, at: vm_mmap_pgoff+0x1ed/0x520 mm/util.c:579 #1: ffff8880373da460 (sb_writers#4){.+.+}-{0:0}, at: file_accessed include/linux/fs.h:2281 [inline] #1: ffff8880373da460 (sb_writers#4){.+.+}-{0:0}, at: ext4_file_mmap_prepare+0x277/0x450 fs/ext4/file.c:919 #2: ffff8880373d8950 (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: 34 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026 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: 33 Comm: pr/ttyS0 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026 RIP: 0010:io_serial_out+0x7c/0xc0 drivers/tty/serial/8250/8250_port.c:432 Code: fa 44 fc 44 89 f9 d3 e5 49 83 c6 40 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 4c cb bb fc 41 03 2e 89 d8 89 ea ee <5b> 41 5c 41 5e 41 5f 5d e9 07 69 79 06 cc 44 89 f9 80 e1 07 38 c1 RSP: 0018:ffffc90000a97900 EFLAGS: 00000002 RAX: 0000000000000035 RBX: 0000000000000035 RCX: 0000000000000000 RDX: 00000000000003f8 RSI: 0000000000000000 RDI: 0000000000000020 RBP: 00000000000003f8 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: ffffffff85840fd0 R12: dffffc0000000000 R13: 0000000000000035 R14: ffffffff9bda86e0 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888123b66000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000564f2d43e608 CR3: 000000007f38a000 CR4: 00000000003526f0 Call Trace: serial_port_out include/linux/serial_core.h:817 [inline] serial8250_console_putchar drivers/tty/serial/8250/8250_port.c:3311 [inline] __serial8250_console_fifo_write+0x1e6/0x3e0 drivers/tty/serial/8250/8250_port.c:3383 serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3402 [inline] __serial8250_console_write drivers/tty/serial/8250/8250_port.c:3456 [inline] serial8250_console_write+0xa7e/0x1200 drivers/tty/serial/8250/8250_port.c:3520 nbcon_emit_next_record+0xef5/0x1a90 kernel/printk/nbcon.c:-1 nbcon_emit_one kernel/printk/nbcon.c:1157 [inline] nbcon_kthread_func+0x6d9/0x8d0 kernel/printk/nbcon.c:1271 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