INFO: task kworker/u4:0:11 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u4:0 state:D stack:21784 pid:11 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 rq_qos_wait+0x22b/0x360 block/blk-rq-qos.c:282 __wbt_wait block/blk-wbt.c:595 [inline] wbt_wait+0x34a/0x580 block/blk-wbt.c:659 __rq_qos_throttle+0x65/0xb0 block/blk-rq-qos.c:66 rq_qos_throttle block/blk-rq-qos.h:151 [inline] blk_mq_get_new_requests block/blk-mq.c:2955 [inline] blk_mq_submit_bio+0x8fb/0x2220 block/blk-mq.c:3056 __submit_bio+0x12b/0x260 block/blk-core.c:610 __submit_bio_noacct_mq block/blk-core.c:689 [inline] submit_bio_noacct_nocheck+0x6e8/0x9c0 block/blk-core.c:718 ext4_io_submit+0xdc/0x140 fs/ext4/page-io.c:389 ext4_do_writepages+0xb5f/0x3990 fs/ext4/inode.c:2678 ext4_writepages+0x1dd/0x350 fs/ext4/inode.c:2810 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/sda1-8:5102 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:25128 pid:5102 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 io_schedule+0x80/0xd0 kernel/sched/core.c:9024 bit_wait_io+0x11/0xd0 kernel/sched/wait_bit.c:209 __wait_on_bit+0x9f/0x2c0 kernel/sched/wait_bit.c:49 out_of_line_wait_on_bit+0x13c/0x190 kernel/sched/wait_bit.c:64 wait_on_buffer include/linux/buffer_head.h:373 [inline] jbd2_journal_commit_transaction+0x2e8d/0x5ad0 fs/jbd2/commit.c:815 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:5762 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:22008 pid:5762 ppid:5761 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 io_schedule+0x80/0xd0 kernel/sched/core.c:9024 bit_wait_io+0x11/0xd0 kernel/sched/wait_bit.c:209 __wait_on_bit+0x9f/0x2c0 kernel/sched/wait_bit.c:49 out_of_line_wait_on_bit+0x13c/0x190 kernel/sched/wait_bit.c:64 wait_on_bit_io include/linux/wait_bit.h:101 [inline] do_get_write_access+0x5c9/0xe00 fs/jbd2/transaction.c:1096 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_reserve_inode_write+0x205/0x2a0 fs/ext4/inode.c:5933 __ext4_mark_inode_dirty+0x13f/0x6d0 fs/ext4/inode.c:6107 ext4_dirty_inode+0xcb/0x110 fs/ext4/inode.c:6144 __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:6262 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: 0033:0x7f3a6a070123 RSP: 002b:00007ffeb0447a90 EFLAGS: 00010206 RAX: 00007f3a62bf23dc RBX: 00007ffeb0447bc0 RCX: 0000000000000000 RDX: 00007f3a62bf23d8 RSI: 0000000000000008 RDI: 00007ffeb0447bc0 RBP: 00000000000003e6 R08: 0000000000000000 R09: 0000000000000000 R10: 00007ffeb0447ba0 R11: 0000000000000000 R12: 0000000000000000 R13: 000000000000dc24 R14: ffffffffffff23dc R15: 0000000000000000 INFO: task syz.7.2124:12879 blocked for more than 144 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.7.2124 state:D stack:27048 pid:12879 ppid:9543 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 io_schedule+0x80/0xd0 kernel/sched/core.c:9024 bit_wait_io+0x11/0xd0 kernel/sched/wait_bit.c:209 __wait_on_bit+0x9f/0x2c0 kernel/sched/wait_bit.c:49 out_of_line_wait_on_bit+0x13c/0x190 kernel/sched/wait_bit.c:64 wait_on_bit_io include/linux/wait_bit.h:101 [inline] do_get_write_access+0x5c9/0xe00 fs/jbd2/transaction.c:1096 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_reserve_inode_write+0x205/0x2a0 fs/ext4/inode.c:5933 __ext4_mark_inode_dirty+0x13f/0x6d0 fs/ext4/inode.c:6107 ext4_dirty_inode+0xcb/0x110 fs/ext4/inode.c:6144 __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:6262 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: 0033:0x7fa7d1472e52 RSP: 002b:00007ffcccab35a0 EFLAGS: 00010202 RAX: 0000000000007008 RBX: 00007fa7d2355720 RCX: 0000000000000000 RDX: 0000001b30c1d000 RSI: 0000000000000008 RDI: 00007fa7d2355720 RBP: 0000000000000057 R08: 00007fa7d1810000 R09: 00007fa7d1826038 R10: 0000000000000007 R11: 0000000000000001 R12: ffffffff81771f67 R13: 00007fa7d1826038 R14: 000000000000003f R15: ffffffffffff9000 INFO: task syz.9.2127:12885 blocked for more than 144 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.9.2127 state:D stack:27560 pid:12885 ppid:11990 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 io_schedule+0x80/0xd0 kernel/sched/core.c:9024 bit_wait_io+0x11/0xd0 kernel/sched/wait_bit.c:209 __wait_on_bit+0x9f/0x2c0 kernel/sched/wait_bit.c:49 out_of_line_wait_on_bit+0x13c/0x190 kernel/sched/wait_bit.c:64 wait_on_bit_io include/linux/wait_bit.h:101 [inline] do_get_write_access+0x5c9/0xe00 fs/jbd2/transaction.c:1096 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_reserve_inode_write+0x205/0x2a0 fs/ext4/inode.c:5933 __ext4_mark_inode_dirty+0x13f/0x6d0 fs/ext4/inode.c:6107 ext4_dirty_inode+0xcb/0x110 fs/ext4/inode.c:6144 __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:6262 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: 0033:0x7f77e406b9e3 RSP: 002b:00007ffecaf6c9a0 EFLAGS: 00010246 RAX: 00000000005ffde8 RBX: 0000000000000000 RCX: 0000001b30e64000 RDX: 0000001b30e24000 RSI: 0000000000600000 RDI: 00007f77e43e0708 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 00007ffecaf6cc30 Showing all locks held in the system: 4 locks held by kworker/u4:0/11: #0: ffff888141274138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2632 [inline] #0: ffff888141274138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2734 #1: ffffc90000107d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2632 [inline] #1: ffffc90000107d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2734 #2: ffff88814e15e0e0 (&type->s_umount_key#32){++++}-{3:3}, at: super_trylock_shared+0x20/0xf0 fs/super.c:607 #3: ffff88814e160c58 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_writepages_down_read fs/ext4/ext4.h:1768 [inline] #3: ffff88814e160c58 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_writepages+0x1a4/0x350 fs/ext4/inode.c:2809 1 lock held by khungtaskd/28: #0: ffffffff8d131da0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline] #0: ffffffff8d131da0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline] #0: ffffffff8d131da0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x290 kernel/locking/lockdep.c:6633 2 locks held by getty/5532: #0: ffff88802cd830a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000327b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x428/0x1370 drivers/tty/n_tty.c:2217 3 locks held by syz-executor/5762: #0: ffff88801e723120 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:165 [inline] #0: ffff88801e723120 (&mm->mmap_lock){++++}-{3:3}, at: get_mmap_lock_carefully mm/memory.c:5380 [inline] #0: ffff88801e723120 (&mm->mmap_lock){++++}-{3:3}, at: lock_mm_and_find_vma+0x32/0x2f0 mm/memory.c:5440 #1: ffff88814e15e510 (sb_pagefaults){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1633 [inline] #1: ffff88814e15e510 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs.h:1737 [inline] #1: ffff88814e15e510 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x1e2/0x11a0 fs/ext4/inode.c:6261 #2: ffff88814e162990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x1f3f/0x2170 fs/jbd2/transaction.c:448 1 lock held by udevd/5767: #0: ffff8880314a85a0 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock_shared include/linux/fs.h:859 [inline] #0: ffff8880314a85a0 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_fault+0x969/0x1540 mm/filemap.c:3345 3 locks held by syz.0.1691/11317: #0: ffff8880268e1748 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2a3/0x330 fs/file.c:1040 #1: ffff888152a90418 (sb_writers#37){.+.+}-{0:0}, at: vfs_write+0x21e/0x9a0 fs/read_write.c:580 #2: ffffffff8d3e1728 (nfsd_mutex){+.+.}-{3:3}, at: write_ports+0xb7/0xfa0 fs/nfsd/nfsctl.c:843 3 locks held by syz.7.2124/12879: #0: ffff88801afe0b20 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:165 [inline] #0: ffff88801afe0b20 (&mm->mmap_lock){++++}-{3:3}, at: get_mmap_lock_carefully mm/memory.c:5380 [inline] #0: ffff88801afe0b20 (&mm->mmap_lock){++++}-{3:3}, at: lock_mm_and_find_vma+0x32/0x2f0 mm/memory.c:5440 #1: ffff88814e15e510 (sb_pagefaults){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1633 [inline] #1: ffff88814e15e510 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs.h:1737 [inline] #1: ffff88814e15e510 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x1e2/0x11a0 fs/ext4/inode.c:6261 #2: ffff88814e162990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x1f3f/0x2170 fs/jbd2/transaction.c:448 3 locks held by syz.9.2127/12885: #0: ffff88801afe5720 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:165 [inline] #0: ffff88801afe5720 (&mm->mmap_lock){++++}-{3:3}, at: get_mmap_lock_carefully mm/memory.c:5380 [inline] #0: ffff88801afe5720 (&mm->mmap_lock){++++}-{3:3}, at: lock_mm_and_find_vma+0x32/0x2f0 mm/memory.c:5440 #1: ffff88814e15e510 (sb_pagefaults){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1633 [inline] #1: ffff88814e15e510 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs.h:1737 [inline] #1: ffff88814e15e510 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x1e2/0x11a0 fs/ext4/inode.c:6261 #2: ffff88814e162990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x1f3f/0x2170 fs/jbd2/transaction.c:448 ============================================= NMI backtrace for cpu 1 CPU: 1 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 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 12033 Comm: kworker/u4:1 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:find_stack lib/stackdepot.c:351 [inline] RIP: 0010:__stack_depot_save+0x162/0x660 lib/stackdepot.c:390 Code: 2d ab a5 fb 12 8b 2d a1 a5 fb 12 44 21 e5 4d 8b 7c ed 00 4d 85 ff 74 31 89 c1 eb 08 4d 8b 3f 4d 85 ff 74 25 45 39 67 08 75 f2 <41> 39 47 0c 75 ec 31 d2 48 8b 34 d3 49 3b 74 d7 18 75 df 48 ff c2 RSP: 0018:ffffc90005367768 EFLAGS: 00000246 RAX: 000000000000000b RBX: ffffc900053677c0 RCX: 000000000000000b RDX: 000000005c61469d RSI: 000000005de74c84 RDI: 0000000000000001 RBP: 00000000000dd914 R08: 0000000000082820 R09: 0000000090282aa1 R10: 00000000803c3c20 R11: 0000000000000000 R12: 00000000d58dd914 R13: ffff88823b400000 R14: 0000000000000001 R15: ffff88805e71a940 FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055fb2fff5168 CR3: 000000000cf32000 CR4: 00000000003506f0 Call Trace: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_set_track+0x5f/0x70 mm/kasan/common.c:53 ____kasan_kmalloc mm/kasan/common.c:375 [inline] __kasan_kmalloc+0x8f/0xa0 mm/kasan/common.c:384 kasan_kmalloc include/linux/kasan.h:198 [inline] __do_kmalloc_node mm/slab_common.c:1007 [inline] __kmalloc_node_track_caller+0xb4/0x230 mm/slab_common.c:1027 kmalloc_reserve+0x116/0x240 net/core/skbuff.c:584 __alloc_skb+0x138/0x2c0 net/core/skbuff.c:653 alloc_skb include/linux/skbuff.h:1316 [inline] nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:748 [inline] nsim_dev_trap_report drivers/net/netdevsim/dev.c:805 [inline] nsim_dev_trap_report_work+0x253/0xa90 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