INFO: task kworker/u4:4:58 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u4:4 state:D stack:23360 pid:58 ppid:2 flags:0x00004000 Workqueue: writeback wb_workfn (flush-8:0) Call Trace: context_switch kernel/sched/core.c:5246 [inline] __schedule+0x107f/0x4030 kernel/sched/core.c:6563 schedule+0xb9/0x180 kernel/sched/core.c:6639 io_schedule+0x7c/0xd0 kernel/sched/core.c:8799 bit_wait_io+0xd/0xc0 kernel/sched/wait_bit.c:209 __wait_on_bit+0x9b/0x2c0 kernel/sched/wait_bit.c:49 out_of_line_wait_on_bit+0x138/0x190 kernel/sched/wait_bit.c:64 wait_on_bit_io include/linux/wait_bit.h:101 [inline] do_get_write_access+0x605/0xf20 fs/jbd2/transaction.c:1115 jbd2_journal_get_write_access+0x108/0x140 fs/jbd2/transaction.c:1250 __ext4_journal_get_write_access+0x24b/0x6e0 fs/ext4/ext4_jbd2.c:235 ext4_mb_mark_diskspace_used+0x1bf/0x1500 fs/ext4/mballoc.c:3838 ext4_mb_new_blocks+0x1170/0x44d0 fs/ext4/mballoc.c:5796 ext4_ext_map_blocks+0x18d1/0x6640 fs/ext4/extents.c:4361 ext4_map_blocks+0x9d7/0x1a90 fs/ext4/inode.c:681 mpage_map_one_extent fs/ext4/inode.c:2436 [inline] mpage_map_and_submit_extent fs/ext4/inode.c:2489 [inline] ext4_writepages+0x12aa/0x2e70 fs/ext4/inode.c:2857 do_writepages+0x3c6/0x640 mm/page-writeback.c:2491 __writeback_single_inode+0x153/0x1170 fs/fs-writeback.c:1673 writeback_sb_inodes+0xad5/0x17f0 fs/fs-writeback.c:1964 __writeback_inodes_wb+0x12a/0x3f0 fs/fs-writeback.c:2035 wb_writeback+0x484/0xd40 fs/fs-writeback.c:2140 wb_check_old_data_flush fs/fs-writeback.c:2240 [inline] wb_do_writeback fs/fs-writeback.c:2293 [inline] wb_workfn+0xb68/0xee0 fs/fs-writeback.c:2321 process_one_work+0x8ab/0x1160 kernel/workqueue.c:2292 worker_thread+0xaf5/0x12a0 kernel/workqueue.c:2439 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 INFO: task jbd2/sda1-8:3601 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:25904 pid:3601 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5246 [inline] __schedule+0x107f/0x4030 kernel/sched/core.c:6563 schedule+0xb9/0x180 kernel/sched/core.c:6639 io_schedule+0x7c/0xd0 kernel/sched/core.c:8799 bit_wait_io+0xd/0xc0 kernel/sched/wait_bit.c:209 __wait_on_bit+0x9b/0x2c0 kernel/sched/wait_bit.c:49 out_of_line_wait_on_bit+0x138/0x190 kernel/sched/wait_bit.c:64 wait_on_buffer include/linux/buffer_head.h:385 [inline] jbd2_journal_commit_transaction+0x2f0f/0x5f30 fs/jbd2/commit.c:849 kjournald2+0x40b/0x800 fs/jbd2/journal.c:210 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 INFO: task syz-executor:4259 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:23024 pid:4259 ppid:4258 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5246 [inline] __schedule+0x107f/0x4030 kernel/sched/core.c:6563 schedule+0xb9/0x180 kernel/sched/core.c:6639 io_schedule+0x7c/0xd0 kernel/sched/core.c:8799 bit_wait_io+0xd/0xc0 kernel/sched/wait_bit.c:209 __wait_on_bit+0x9b/0x2c0 kernel/sched/wait_bit.c:49 out_of_line_wait_on_bit+0x138/0x190 kernel/sched/wait_bit.c:64 wait_on_bit_io include/linux/wait_bit.h:101 [inline] do_get_write_access+0x605/0xf20 fs/jbd2/transaction.c:1115 jbd2_journal_get_write_access+0x108/0x140 fs/jbd2/transaction.c:1250 __ext4_journal_get_write_access+0x24b/0x6e0 fs/ext4/ext4_jbd2.c:235 ext4_reserve_inode_write+0x201/0x290 fs/ext4/inode.c:5945 __ext4_mark_inode_dirty+0x161/0x760 fs/ext4/inode.c:6119 ext4_dirty_inode+0xbf/0x100 fs/ext4/inode.c:6156 __mark_inode_dirty+0x2e7/0xe80 fs/fs-writeback.c:2500 generic_update_time fs/inode.c:1946 [inline] inode_update_time fs/inode.c:1959 [inline] __file_update_time+0x21d/0x240 fs/inode.c:2147 file_update_time+0x2f3/0x370 fs/inode.c:2178 ext4_page_mkwrite+0x1a9/0x10d0 fs/ext4/inode.c:6274 do_page_mkwrite+0x16b/0x5c0 mm/memory.c:3009 wp_page_shared+0x167/0x370 mm/memory.c:3358 handle_pte_fault mm/memory.c:5047 [inline] __handle_mm_fault mm/memory.c:5171 [inline] handle_mm_fault+0x1b1b/0x3d40 mm/memory.c:5292 do_user_addr_fault+0x58e/0xb20 arch/x86/mm/fault.c:1338 handle_page_fault arch/x86/mm/fault.c:1429 [inline] exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1482 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:608 RIP: 0033:0x7fcb63e70163 RSP: 002b:00007ffd2d8f7700 EFLAGS: 00010216 RAX: 00007fcb5b3fe714 RBX: 00007ffd2d8f7830 RCX: 0000000000000000 RDX: 00007fcb5b3fe710 RSI: 0000000000000008 RDI: 00007ffd2d8f7830 RBP: 00000000000003e6 R08: 0000000000000000 R09: 0000000000000000 R10: 00007ffd2d8f7810 R11: 0000000000000000 R12: 0000000000000000 R13: 00000000000018ec R14: ffffffffffffe714 R15: 0000000000000000 INFO: task syz.3.89:4664 blocked for more than 144 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.3.89 state:D stack:26256 pid:4664 ppid:4280 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5246 [inline] __schedule+0x107f/0x4030 kernel/sched/core.c:6563 schedule+0xb9/0x180 kernel/sched/core.c:6639 io_schedule+0x7c/0xd0 kernel/sched/core.c:8799 bit_wait_io+0xd/0xc0 kernel/sched/wait_bit.c:209 __wait_on_bit+0x9b/0x2c0 kernel/sched/wait_bit.c:49 out_of_line_wait_on_bit+0x138/0x190 kernel/sched/wait_bit.c:64 wait_on_bit_io include/linux/wait_bit.h:101 [inline] do_get_write_access+0x605/0xf20 fs/jbd2/transaction.c:1115 jbd2_journal_get_write_access+0x108/0x140 fs/jbd2/transaction.c:1250 __ext4_journal_get_write_access+0x24b/0x6e0 fs/ext4/ext4_jbd2.c:235 ext4_reserve_inode_write+0x201/0x290 fs/ext4/inode.c:5945 __ext4_mark_inode_dirty+0x161/0x760 fs/ext4/inode.c:6119 ext4_dirty_inode+0xbf/0x100 fs/ext4/inode.c:6156 __mark_inode_dirty+0x2e7/0xe80 fs/fs-writeback.c:2500 generic_update_time fs/inode.c:1946 [inline] inode_update_time fs/inode.c:1959 [inline] __file_update_time+0x21d/0x240 fs/inode.c:2147 file_update_time+0x2f3/0x370 fs/inode.c:2178 ext4_page_mkwrite+0x1a9/0x10d0 fs/ext4/inode.c:6274 do_page_mkwrite+0x16b/0x5c0 mm/memory.c:3009 do_shared_fault mm/memory.c:4694 [inline] do_fault mm/memory.c:4762 [inline] handle_pte_fault mm/memory.c:5029 [inline] __handle_mm_fault mm/memory.c:5171 [inline] handle_mm_fault+0x199c/0x3d40 mm/memory.c:5292 do_user_addr_fault+0x58e/0xb20 arch/x86/mm/fault.c:1338 handle_page_fault arch/x86/mm/fault.c:1429 [inline] exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1482 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:608 RIP: 0033:0x7f175d272789 RSP: 002b:00007ffe427a3b50 EFLAGS: 00010202 RAX: 0000001b30024000 RBX: 0000000000000000 RCX: 00000000005ffde8 RDX: 0000001b30023ffc RSI: 00000000005ffde8 RDI: 00007f175e155700 RBP: 0000000000000000 R08: 0000000000000000 R09: 00007f175d612000 R10: 00007f175e155700 R11: 0000000000000000 R12: 0000000000000000 R13: 000000000000307f R14: ffffffff812f829c R15: 00007f175e155720 Showing all locks held in the system: 2 locks held by kworker/u4:1/11: #0: ffff8880b8f3ad18 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x25/0x130 kernel/sched/core.c:538 #1: ffff8880b8f27888 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x36b/0x740 kernel/sched/psi.c:987 1 lock held by rcu_tasks_kthre/12: #0: ffffffff8cb2e4f0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xef0 kernel/rcu/tasks.h:517 1 lock held by rcu_tasks_trace/13: #0: ffffffff8cb2ed10 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xef0 kernel/rcu/tasks.h:517 1 lock held by khungtaskd/27: #0: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #0: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #0: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6527 6 locks held by kworker/u4:4/58: #0: ffff888141a55938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267 #1: ffffc90001597d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267 #2: ffff88807e3a00e0 (&type->s_umount_key#32){++++}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:415 #3: ffff88807e3a2c18 (&sbi->s_writepages_rwsem){.+.+}-{0:0}, at: ext4_writepages+0x213/0x2e70 fs/ext4/inode.c:2717 #4: ffff88807e3a4990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x2014/0x2240 fs/jbd2/transaction.c:463 #5: ffff888074312aa8 (&ei->i_data_sem){++++}-{3:3}, at: ext4_map_blocks+0x914/0x1a90 fs/ext4/inode.c:674 2 locks held by getty/4026: #0: ffff888030503098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244 #1: ffffc9000327e2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x41e/0x1360 drivers/tty/n_tty.c:2198 3 locks held by syz-executor/4259: #0: ffff88801a79ea58 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline] #0: ffff88801a79ea58 (&mm->mmap_lock){++++}-{3:3}, at: get_mmap_lock_carefully mm/memory.c:5320 [inline] #0: ffff88801a79ea58 (&mm->mmap_lock){++++}-{3:3}, at: lock_mm_and_find_vma+0x2e/0x2f0 mm/memory.c:5382 #1: ffff88807e3a0558 (sb_pagefaults){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1891 [inline] #1: ffff88807e3a0558 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs.h:1995 [inline] #1: ffff88807e3a0558 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x192/0x10d0 fs/ext4/inode.c:6273 #2: ffff88807e3a4990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x2014/0x2240 fs/jbd2/transaction.c:463 1 lock held by syz.1.75/4597: #0: ffff888054bce460 (sb_writers#5){.+.+}-{0:0}, at: do_coredump+0x169d/0x2480 fs/coredump.c:823 3 locks held by syz.3.89/4664: #0: ffff88807bd63d58 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline] #0: ffff88807bd63d58 (&mm->mmap_lock){++++}-{3:3}, at: get_mmap_lock_carefully mm/memory.c:5320 [inline] #0: ffff88807bd63d58 (&mm->mmap_lock){++++}-{3:3}, at: lock_mm_and_find_vma+0x2e/0x2f0 mm/memory.c:5382 #1: ffff88807e3a0558 (sb_pagefaults){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1891 [inline] #1: ffff88807e3a0558 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs.h:1995 [inline] #1: ffff88807e3a0558 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x192/0x10d0 fs/ext4/inode.c:6273 #2: ffff88807e3a4990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x2014/0x2240 fs/jbd2/transaction.c:463 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 27 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+0x188/0x24e lib/dump_stack.c:106 nmi_cpu_backtrace+0x3e6/0x460 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x1d4/0x450 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline] watchdog+0xf0e/0xf50 kernel/hung_task.c:377 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 3621 Comm: syslogd Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 RIP: 0010:mark_lock_accessed kernel/locking/lockdep.c:1512 [inline] RIP: 0010:__bfs kernel/locking/lockdep.c:1750 [inline] RIP: 0010:__bfs_backwards kernel/locking/lockdep.c:1842 [inline] RIP: 0010:check_irq_usage kernel/locking/lockdep.c:2787 [inline] RIP: 0010:check_prev_add kernel/locking/lockdep.c:3099 [inline] RIP: 0010:check_prevs_add kernel/locking/lockdep.c:3214 [inline] RIP: 0010:validate_chain kernel/locking/lockdep.c:3830 [inline] RIP: 0010:__lock_acquire+0x313c/0x7c40 kernel/locking/lockdep.c:5063 Code: 4c 4d 89 fc 49 c1 ec 03 41 0f b6 04 14 84 c0 0f 85 78 03 00 00 44 8b 2d c2 18 52 11 45 39 2f 0f 84 a6 fe ff ff 41 0f b6 04 14 <84> c0 0f 85 a1 03 00 00 45 89 2f 4d 8d 7e 30 4c 89 f8 48 c1 e8 03 RSP: 0018:ffffc90003287460 EFLAGS: 00000087 RAX: 0000000000000000 RBX: 1ffffffff2696a69 RCX: 000000000000006f RDX: dffffc0000000000 RSI: 0000000000000000 RDI: ffffffff934c0f18 RBP: ffffc90003287690 R08: ffffc90003287617 R09: ffffc900032875e0 R10: dffffc0000000000 R11: fffff52000650ec3 R12: 1ffffffff2097dc9 R13: 0000000000016622 R14: ffffffff934b5338 R15: ffffffff904bee4c FS: 00007fdd03623c80(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000564a4b375660 CR3: 000000007e478000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_acquire+0x1bb/0x4a0 kernel/locking/lockdep.c:5676 _raw_spin_lock_nested+0x2e/0x40 kernel/locking/spinlock.c:378 raw_spin_rq_lock_nested+0x25/0x130 kernel/sched/core.c:538 raw_spin_rq_lock kernel/sched/sched.h:1362 [inline] rq_lock kernel/sched/sched.h:1652 [inline] ttwu_queue kernel/sched/core.c:3903 [inline] try_to_wake_up+0x4e2/0x10b0 kernel/sched/core.c:4228 autoremove_wake_function+0x13/0xf0 kernel/sched/wait.c:419 __wake_up_common+0x28e/0x4d0 kernel/sched/wait.c:107 __wake_up_common_lock kernel/sched/wait.c:138 [inline] __wake_up_sync_key+0x11a/0x190 kernel/sched/wait.c:208 __unix_dgram_recvmsg+0x4b7/0xd90 net/unix/af_unix.c:2478 sock_recvmsg_nosec net/socket.c:1023 [inline] sock_recvmsg net/socket.c:1041 [inline] sock_read_iter+0x2da/0x3a0 net/socket.c:1122 call_read_iter include/linux/fs.h:2259 [inline] new_sync_read fs/read_write.c:389 [inline] vfs_read+0x471/0x960 fs/read_write.c:470 ksys_read+0x14d/0x260 fs/read_write.c:613 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fdd03773407 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:00007ffdf09fded0 EFLAGS: 00000202 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 00007fdd03623c80 RCX: 00007fdd03773407 RDX: 00000000000000ff RSI: 000055e577166950 RDI: 0000000000000000 RBP: 000055e577166910 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 000055e577166982 R13: 0000000000000000 R14: 000055e577166950 R15: 000055e5436bbd98