INFO: task kworker/u4:11:3482 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u4:11 state:D stack:21848 pid:3482 ppid:2 flags:0x00004000 Workqueue: writeback wb_workfn (flush-8:0) Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x15ae/0x4660 kernel/sched/core.c:6701 schedule+0xbd/0x170 kernel/sched/core.c:6775 io_schedule+0x80/0xd0 kernel/sched/core.c:9024 bit_wait_io+0x11/0xd0 kernel/sched/wait_bit.c:209 __wait_on_bit_lock+0xc2/0x560 kernel/sched/wait_bit.c:90 out_of_line_wait_on_bit_lock+0x13c/0x190 kernel/sched/wait_bit.c:117 lock_buffer include/linux/buffer_head.h:385 [inline] do_get_write_access+0x1a9/0xe00 fs/jbd2/transaction.c:972 jbd2_journal_get_write_access+0x10c/0x140 fs/jbd2/transaction.c:1231 __ext4_journal_get_write_access+0x208/0x6d0 fs/ext4/ext4_jbd2.c:241 ext4_mb_mark_diskspace_used+0x1c3/0x14b0 fs/ext4/mballoc.c:4036 ext4_mb_new_blocks+0x105b/0x42f0 fs/ext4/mballoc.c:6272 ext4_ext_map_blocks+0x1811/0x68c0 fs/ext4/extents.c:4416 ext4_map_blocks+0x9db/0x1a90 fs/ext4/inode.c:654 mpage_map_one_extent fs/ext4/inode.c:2205 [inline] mpage_map_and_submit_extent fs/ext4/inode.c:2258 [inline] ext4_do_writepages+0x1463/0x3990 fs/ext4/inode.c:2733 ext4_writepages+0x1dd/0x350 fs/ext4/inode.c:2822 do_writepages+0x351/0x590 mm/page-writeback.c:2575 __writeback_single_inode+0x14e/0xee0 fs/fs-writeback.c:1686 writeback_sb_inodes+0x813/0x1020 fs/fs-writeback.c:1977 __writeback_inodes_wb+0x114/0x240 fs/fs-writeback.c:2048 wb_writeback+0x472/0xbe0 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+0xad7/0xe60 fs/fs-writeback.c:2343 process_one_work kernel/workqueue.c:2657 [inline] process_scheduled_works+0xa60/0x1600 kernel/workqueue.c:2734 worker_thread+0xa5e/0xfe0 kernel/workqueue.c:2815 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 INFO: task jbd2/sda1-8:5104 blocked 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:26024 pid:5104 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x15ae/0x4660 kernel/sched/core.c:6701 schedule+0xbd/0x170 kernel/sched/core.c:6775 jbd2_journal_wait_updates+0x19b/0x270 fs/jbd2/transaction.c:847 jbd2_journal_commit_transaction+0x90f/0x5ad0 fs/jbd2/commit.c:454 kjournald2+0x40f/0x810 fs/jbd2/journal.c:201 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 INFO: task syz-executor:5766 blocked for more than 144 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:22888 pid:5766 ppid:5765 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x15ae/0x4660 kernel/sched/core.c:6701 schedule+0xbd/0x170 kernel/sched/core.c:6775 wait_transaction_locked+0x1d7/0x270 fs/jbd2/transaction.c:156 add_transaction_credits fs/jbd2/transaction.c:226 [inline] start_this_handle+0x7e8/0x2170 fs/jbd2/transaction.c:407 jbd2__journal_start+0x2bb/0x5b0 fs/jbd2/transaction.c:505 __ext4_journal_start_sb+0x203/0x560 fs/ext4/ext4_jbd2.c:112 __ext4_journal_start fs/ext4/ext4_jbd2.h:326 [inline] ext4_dirty_inode+0x93/0x110 fs/ext4/inode.c:6163 __mark_inode_dirty+0x2cc/0xc90 fs/fs-writeback.c:2522 generic_update_time fs/inode.c:1981 [inline] inode_update_time fs/inode.c:1994 [inline] __file_update_time fs/inode.c:2180 [inline] file_update_time+0x187/0x1a0 fs/inode.c:2210 ext4_page_mkwrite+0x1f9/0x11a0 fs/ext4/inode.c:6284 do_page_mkwrite+0x153/0x3f0 mm/memory.c:2951 wp_page_shared mm/memory.c:3311 [inline] do_wp_page+0xd4d/0x34d0 mm/memory.c:3396 handle_pte_fault mm/memory.c:5063 [inline] __handle_mm_fault mm/memory.c:5188 [inline] handle_mm_fault+0x1306/0x4a50 mm/memory.c:5353 do_user_addr_fault+0x736/0x12d0 arch/x86/mm/fault.c:1371 handle_page_fault arch/x86/mm/fault.c:1463 [inline] exc_page_fault+0x64/0x100 arch/x86/mm/fault.c:1516 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:608 RIP: 0033:0x7fa7ae4701e3 RSP: 002b:00007ffe2766be20 EFLAGS: 00010206 RAX: 00007fa7ab1ff108 RBX: 00007ffe2766bf50 RCX: 0000000000000000 RDX: 00007fa7ab1ff104 RSI: 0000000000000008 RDI: 00007ffe2766bf50 RBP: 00000000000003e6 R08: 0000000000000000 R09: 0000000000000000 R10: 00007ffe2766bf30 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000ef8 R14: fffffffffffff108 R15: 0000000000000000 INFO: task syz.3.772:7826 blocked for more than 144 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.3.772 state:D stack:25384 pid:7826 ppid:5782 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x15ae/0x4660 kernel/sched/core.c:6701 schedule+0xbd/0x170 kernel/sched/core.c:6775 wait_transaction_locked+0x1d7/0x270 fs/jbd2/transaction.c:156 add_transaction_credits fs/jbd2/transaction.c:226 [inline] start_this_handle+0x7e8/0x2170 fs/jbd2/transaction.c:407 jbd2__journal_start+0x2bb/0x5b0 fs/jbd2/transaction.c:505 __ext4_journal_start_sb+0x203/0x560 fs/ext4/ext4_jbd2.c:112 __ext4_journal_start fs/ext4/ext4_jbd2.h:326 [inline] ext4_dirty_inode+0x93/0x110 fs/ext4/inode.c:6163 __mark_inode_dirty+0x2cc/0xc90 fs/fs-writeback.c:2522 generic_update_time fs/inode.c:1981 [inline] inode_update_time fs/inode.c:1994 [inline] __file_update_time fs/inode.c:2180 [inline] file_update_time+0x187/0x1a0 fs/inode.c:2210 ext4_page_mkwrite+0x1f9/0x11a0 fs/ext4/inode.c:6284 do_page_mkwrite+0x153/0x3f0 mm/memory.c:2951 do_shared_fault mm/memory.c:4717 [inline] do_fault mm/memory.c:4779 [inline] do_pte_missing mm/memory.c:3689 [inline] handle_pte_fault mm/memory.c:5047 [inline] __handle_mm_fault mm/memory.c:5188 [inline] handle_mm_fault+0x1a2c/0x4a50 mm/memory.c:5353 do_user_addr_fault+0x736/0x12d0 arch/x86/mm/fault.c:1371 handle_page_fault arch/x86/mm/fault.c:1463 [inline] exc_page_fault+0x64/0x100 arch/x86/mm/fault.c:1516 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:608 RIP: 0033:0x7f9bdba727a9 RSP: 002b:00007ffd075ebeb0 EFLAGS: 00010202 RAX: 0000001b2e21e000 RBX: ffffffff884a03d0 RCX: 0000001b2e21dff8 RDX: 0000001b2dc24220 RSI: 0000000000000008 RDI: 00007f9bdc955720 RBP: 0000000000000292 R08: 00007f9bdbe10000 R09: 00007f9bdbe12000 R10: 00000000884a03d4 R11: 0000000000000001 R12: 00007f9bdbe26038 R13: 00000000000455a0 R14: ffffffff884a03d8 R15: 00007f9bdc955720 INFO: task syz.1.775:7835 blocked for more than 144 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.1.775 state:D stack:27048 pid:7835 ppid:5787 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x15ae/0x4660 kernel/sched/core.c:6701 schedule+0xbd/0x170 kernel/sched/core.c:6775 wait_transaction_locked+0x1d7/0x270 fs/jbd2/transaction.c:156 add_transaction_credits fs/jbd2/transaction.c:226 [inline] start_this_handle+0x7e8/0x2170 fs/jbd2/transaction.c:407 jbd2__journal_start+0x2bb/0x5b0 fs/jbd2/transaction.c:505 __ext4_journal_start_sb+0x203/0x560 fs/ext4/ext4_jbd2.c:112 __ext4_journal_start fs/ext4/ext4_jbd2.h:326 [inline] ext4_dirty_inode+0x93/0x110 fs/ext4/inode.c:6163 __mark_inode_dirty+0x2cc/0xc90 fs/fs-writeback.c:2522 generic_update_time fs/inode.c:1981 [inline] inode_update_time fs/inode.c:1994 [inline] __file_update_time fs/inode.c:2180 [inline] file_update_time+0x187/0x1a0 fs/inode.c:2210 ext4_page_mkwrite+0x1f9/0x11a0 fs/ext4/inode.c:6284 do_page_mkwrite+0x153/0x3f0 mm/memory.c:2951 do_shared_fault mm/memory.c:4717 [inline] do_fault mm/memory.c:4779 [inline] do_pte_missing mm/memory.c:3689 [inline] handle_pte_fault mm/memory.c:5047 [inline] __handle_mm_fault mm/memory.c:5188 [inline] handle_mm_fault+0x1a2c/0x4a50 mm/memory.c:5353 do_user_addr_fault+0x736/0x12d0 arch/x86/mm/fault.c:1371 handle_page_fault arch/x86/mm/fault.c:1463 [inline] exc_page_fault+0x64/0x100 arch/x86/mm/fault.c:1516 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:608 RIP: 0033:0x7f1a61272809 RSP: 002b:00007ffef6824d90 EFLAGS: 00010202 RAX: 0000001b2e024000 RBX: 0000000000000000 RCX: 00000000005ffde8 RDX: 0000001b2e023ffc RSI: 00000000005ffde8 RDI: 00007f1a62155700 RBP: 0000000000000000 R08: 0000000000000000 R09: 00007f1a61612000 R10: 00007f1a62155700 R11: 0000000000000000 R12: 0000000000000000 R13: 000000000007ffff R14: ffffffff83cbbf00 R15: 00007f1a62155720 INFO: task syz-executor:7840 blocked for more than 145 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:21800 pid:7840 ppid:7819 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x15ae/0x4660 kernel/sched/core.c:6701 schedule+0xbd/0x170 kernel/sched/core.c:6775 wait_transaction_locked+0x1d7/0x270 fs/jbd2/transaction.c:156 add_transaction_credits fs/jbd2/transaction.c:226 [inline] start_this_handle+0x7e8/0x2170 fs/jbd2/transaction.c:407 jbd2__journal_start+0x2bb/0x5b0 fs/jbd2/transaction.c:505 __ext4_journal_start_sb+0x203/0x560 fs/ext4/ext4_jbd2.c:112 __ext4_new_inode+0x13c7/0x3aa0 fs/ext4/ialloc.c:1091 ext4_mkdir+0x40b/0xc90 fs/ext4/namei.c:3068 vfs_mkdir+0x2a5/0x470 fs/namei.c:4168 do_mkdirat+0x1dc/0x450 fs/namei.c:4191 __do_sys_mkdirat fs/namei.c:4206 [inline] __se_sys_mkdirat fs/namei.c:4204 [inline] __x64_sys_mkdirat+0x89/0xa0 fs/namei.c:4204 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f797479cfc7 RSP: 002b:00007fffb2e763d8 EFLAGS: 00000206 ORIG_RAX: 0000000000000102 RAX: ffffffffffffffda RBX: 00007f7974834aaf RCX: 00007f797479cfc7 RDX: 00000000000001ff RSI: 00007f7974834aaf RDI: 00000000ffffff9c RBP: 00007f7974a267b8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000008 R13: 0000000000000003 R14: 00007fffb2e76648 R15: 0000000000000000 Showing all locks held in the system: 1 lock held by khungtaskd/28: #0: ffffffff8d1320e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline] #0: ffffffff8d1320e0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline] #0: ffffffff8d1320e0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x290 kernel/locking/lockdep.c:6635 1 lock held by kworker/u4:6/1127: #0: ffff8880b8f3c258 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x29/0x130 kernel/sched/core.c:559 6 locks held by kworker/u4:11/3482: #0: ffff88801ce64538 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2632 [inline] #0: ffff88801ce64538 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2734 #1: ffffc9000c987d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2632 [inline] #1: ffffc9000c987d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2734 #2: ffff88814d9460e0 (&type->s_umount_key#31){++++}-{3:3}, at: super_trylock_shared+0x20/0xf0 fs/super.c:607 #3: ffff88814d948c58 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_writepages_down_read fs/ext4/ext4.h:1768 [inline] #3: ffff88814d948c58 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_writepages+0x1a4/0x350 fs/ext4/inode.c:2821 #4: ffff88814d94a990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x1f3f/0x2170 fs/jbd2/transaction.c:448 #5: ffff88807922f088 (&ei->i_data_sem){++++}-{3:3}, at: ext4_map_blocks+0x918/0x1a90 fs/ext4/inode.c:647 2 locks held by getty/5535: #0: ffff88814c1be0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc900032832f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x428/0x1370 drivers/tty/n_tty.c:2217 2 locks held by syz-executor/5766: #0: ffff88802f8fc420 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:165 [inline] #0: ffff88802f8fc420 (&mm->mmap_lock){++++}-{3:3}, at: get_mmap_lock_carefully mm/memory.c:5380 [inline] #0: ffff88802f8fc420 (&mm->mmap_lock){++++}-{3:3}, at: lock_mm_and_find_vma+0x32/0x2f0 mm/memory.c:5440 #1: ffff88814d946510 (sb_pagefaults){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1633 [inline] #1: ffff88814d946510 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs.h:1737 [inline] #1: ffff88814d946510 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x1e2/0x11a0 fs/ext4/inode.c:6283 2 locks held by syz.3.772/7826: #0: ffff88802d5d73a0 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:165 [inline] #0: ffff88802d5d73a0 (&mm->mmap_lock){++++}-{3:3}, at: get_mmap_lock_carefully mm/memory.c:5380 [inline] #0: ffff88802d5d73a0 (&mm->mmap_lock){++++}-{3:3}, at: lock_mm_and_find_vma+0x32/0x2f0 mm/memory.c:5440 #1: ffff88814d946510 (sb_pagefaults){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1633 [inline] #1: ffff88814d946510 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs.h:1737 [inline] #1: ffff88814d946510 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x1e2/0x11a0 fs/ext4/inode.c:6283 2 locks held by syz.1.775/7835: #0: ffff88802d5d3120 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:165 [inline] #0: ffff88802d5d3120 (&mm->mmap_lock){++++}-{3:3}, at: get_mmap_lock_carefully mm/memory.c:5380 [inline] #0: ffff88802d5d3120 (&mm->mmap_lock){++++}-{3:3}, at: lock_mm_and_find_vma+0x32/0x2f0 mm/memory.c:5440 #1: ffff88814d946510 (sb_pagefaults){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1633 [inline] #1: ffff88814d946510 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs.h:1737 [inline] #1: ffff88814d946510 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x1e2/0x11a0 fs/ext4/inode.c:6283 2 locks held by syz-executor/7840: #0: ffff88814d946418 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:412 #1: ffff8880793f3610 (&type->i_mutex_dir_key#3/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:839 [inline] #1: ffff8880793f3610 (&type->i_mutex_dir_key#3/1){+.+.}-{3:3}, at: filename_create+0x20f/0x450 fs/namei.c:3937 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 28 Comm: khungtaskd Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Call Trace: dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106 nmi_cpu_backtrace+0x3a6/0x3e0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/0x2f0 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline] watchdog+0xf59/0xfa0 kernel/hung_task.c:379 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 3458 Comm: kworker/u4:10 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Workqueue: events_unbound nsim_dev_trap_report_work RIP: 0010:__lock_acquire+0x12df/0x7d80 kernel/locking/lockdep.c:5134 Code: 31 db 48 83 c3 40 48 89 d8 48 c1 e8 03 42 80 3c 00 00 74 12 48 89 df e8 bf 68 77 00 49 b8 00 00 00 00 00 fc ff df 48 83 3b 00 <0f> 84 94 05 00 00 49 c1 e4 20 48 8b 44 24 58 42 0f b6 04 00 84 c0 RSP: 0018:ffffc9000c867740 EFLAGS: 00000082 RAX: 1ffffffff217646c RBX: ffffffff90bb2360 RCX: ffffffff8168ae42 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff911eb5e8 RBP: ffffc9000c867988 R08: dffffc0000000000 R09: 1ffffffff223d6bd R10: dffffc0000000000 R11: fffffbfff223d6be R12: 0000000007e8bc02 R13: ffff88802e815a00 R14: 0000000023f4c8a9 R15: ffff88802e816580 FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000563aa1c7d168 CR3: 000000000cf32000 CR4: 00000000003506e0 Call Trace: lock_acquire+0x19e/0x420 kernel/locking/lockdep.c:5756 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:351 [inline] nsim_dev_trap_report drivers/net/netdevsim/dev.c:791 [inline] nsim_dev_trap_report_work+0x190/0xa90 drivers/net/netdevsim/dev.c:851 process_one_work kernel/workqueue.c:2657 [inline] process_scheduled_works+0xa60/0x1600 kernel/workqueue.c:2734 worker_thread+0xa5e/0xfe0 kernel/workqueue.c:2815 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293