INFO: task kworker/u4:4:59 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:20904 pid:59 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+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_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:1701 writeback_sb_inodes+0x813/0x1020 fs/fs-writeback.c:1992 __writeback_inodes_wb+0x114/0x240 fs/fs-writeback.c:2063 wb_writeback+0x472/0xbe0 fs/fs-writeback.c:2173 wb_check_old_data_flush fs/fs-writeback.c:2277 [inline] wb_do_writeback fs/fs-writeback.c:2330 [inline] wb_workfn+0xad7/0xe60 fs/fs-writeback.c:2358 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 syz.0.125:6039 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.0.125 state:D stack:27536 pid:6039 ppid:5892 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:5945 __ext4_mark_inode_dirty+0x13f/0x720 fs/ext4/inode.c:6129 ext4_dirty_inode+0xcb/0x110 fs/ext4/inode.c:6166 __mark_inode_dirty+0x2cc/0xc90 fs/fs-writeback.c:2537 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: 0033:0x7f707226bb23 RSP: 002b:00007fff72eb3c50 EFLAGS: 00010246 RAX: 000000000003fde8 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000001b2cf24000 RSI: 0000000000040000 RDI: 00007f70725e2708 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 00007fff72eb3ee0 Showing all locks held in the system: 1 lock held by khungtaskd/29: #0: ffffffff8df320e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline] #0: ffffffff8df320e0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline] #0: ffffffff8df320e0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x290 kernel/locking/lockdep.c:6669 6 locks held by kworker/u4:4/59: #0: ffff888140058138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2632 [inline] #0: ffff888140058138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2734 #1: ffffc900015a7d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2632 [inline] #1: ffffc900015a7d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2734 #2: ffff88814e2740e0 (&type->s_umount_key#31){++++}-{3:3}, at: super_trylock_shared+0x20/0xf0 fs/super.c:607 #3: ffff88814e276c58 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_writepages_down_read fs/ext4/ext4.h:1768 [inline] #3: ffff88814e276c58 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_writepages+0x1a4/0x350 fs/ext4/inode.c:2821 #4: ffff8880329c0990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x1f3f/0x2170 fs/jbd2/transaction.c:448 #5: ffff888076d5b488 (&ei->i_data_sem){++++}-{3:3}, at: ext4_map_blocks+0x918/0x1a90 fs/ext4/inode.c:647 2 locks held by getty/5531: #0: ffff888032a180a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000327e2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x428/0x1370 drivers/tty/n_tty.c:2217 3 locks held by syz.0.125/6039: #0: ffff88807e3f14a0 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:165 [inline] #0: ffff88807e3f14a0 (&mm->mmap_lock){++++}-{3:3}, at: get_mmap_lock_carefully mm/memory.c:5380 [inline] #0: ffff88807e3f14a0 (&mm->mmap_lock){++++}-{3:3}, at: lock_mm_and_find_vma+0x32/0x2f0 mm/memory.c:5440 #1: ffff88814e274510 (sb_pagefaults){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1633 [inline] #1: ffff88814e274510 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs.h:1737 [inline] #1: ffff88814e274510 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x1e2/0x11a0 fs/ext4/inode.c:6283 #2: ffff8880329c0990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x1f3f/0x2170 fs/jbd2/transaction.c:448 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 29 Comm: khungtaskd Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026 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: 3897 Comm: kworker/u4:12 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026 Workqueue: events_unbound cfg80211_wiphy_work RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:26 [inline] RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:89 [inline] RIP: 0010:check_preemption_disabled+0x56/0x110 lib/smp_processor_id.c:19 Code: 74 1f 65 48 8b 0c 25 28 00 00 00 48 3b 4c 24 08 0f 85 c4 00 00 00 48 83 c4 10 5b 41 5e 41 5f 5d c3 48 c7 04 24 00 00 00 00 9c <8f> 04 24 f7 04 24 00 02 00 00 74 cc 65 4c 8b 3d 06 97 70 75 41 f6 RSP: 0018:ffffc9000d6f7658 EFLAGS: 00000046 RAX: 0000000000000000 RBX: ffff88802fb9da00 RCX: 0000000080000000 RDX: ffff88802fb9da00 RSI: ffffffff8acadcc0 RDI: ffffffff8b1d5160 RBP: 00000000ffffffff R08: dffffc0000000000 R09: 1ffffffff23fe2a0 R10: dffffc0000000000 R11: fffffbfff23fe2a1 R12: 1ffff92001adeee4 R13: 0000000000000246 R14: ffffffff8df320e0 R15: 00000000ffffffff FS: 0000000000000000(0000) GS:ffff8880b8c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055c84346f660 CR3: 000000000dd32000 CR4: 00000000003506f0 Call Trace: lockdep_recursion_inc kernel/locking/lockdep.c:462 [inline] lock_is_held_type+0x79/0x190 kernel/locking/lockdep.c:5860 ieee80211_bss_info_update+0x469/0x9f0 net/mac80211/scan.c:199 ieee80211_rx_bss_info net/mac80211/ibss.c:1124 [inline] ieee80211_rx_mgmt_probe_beacon net/mac80211/ibss.c:1613 [inline] ieee80211_ibss_rx_queued_mgmt+0x18f5/0x2dc0 net/mac80211/ibss.c:1642 ieee80211_iface_process_skb net/mac80211/iface.c:1690 [inline] ieee80211_iface_work+0x730/0xc90 net/mac80211/iface.c:1744 cfg80211_wiphy_work+0x228/0x260 net/wireless/core.c:437 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