INFO: task kworker/u4:0:9 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:22352 pid:9 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
rq_qos_wait+0x227/0x350 block/blk-rq-qos.c:282
__wbt_wait block/blk-wbt.c:522 [inline]
wbt_wait+0x384/0x650 block/blk-wbt.c:586
__rq_qos_throttle+0x61/0xa0 block/blk-rq-qos.c:66
rq_qos_throttle block/blk-rq-qos.h:207 [inline]
blk_mq_get_new_requests block/blk-mq.c:2924 [inline]
blk_mq_submit_bio+0x8ef/0x2100 block/blk-mq.c:3023
__submit_bio+0x1a2/0x290 block/blk-core.c:591
__submit_bio_noacct_mq block/blk-core.c:668 [inline]
submit_bio_noacct_nocheck+0x79b/0xaa0 block/blk-core.c:697
ext4_io_submit+0xd8/0x140 fs/ext4/page-io.c:378
ext4_writepages+0x9f4/0x2e70 fs/ext4/inode.c:2815
do_writepages+0x3c6/0x640 mm/page-writeback.c:2491
__writeback_single_inode+0x153/0x1170 fs/fs-writeback.c:1688
writeback_sb_inodes+0xad5/0x17f0 fs/fs-writeback.c:1979
__writeback_inodes_wb+0x12a/0x3f0 fs/fs-writeback.c:2050
wb_writeback+0x484/0xd40 fs/fs-writeback.c:2155
wb_check_old_data_flush fs/fs-writeback.c:2255 [inline]
wb_do_writeback fs/fs-writeback.c:2308 [inline]
wb_workfn+0xb68/0xee0 fs/fs-writeback.c:2336
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 syz.4.3238:14171 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.3238 state:D stack:27600 pid:14171 ppid:4277 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_lock+0xbe/0x560 kernel/sched/wait_bit.c:90
out_of_line_wait_on_bit_lock+0x138/0x190 kernel/sched/wait_bit.c:117
lock_buffer include/linux/buffer_head.h:397 [inline]
do_get_write_access+0x1bc/0xf20 fs/jbd2/transaction.c:991
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+0x161/0x7b0 fs/ext4/inode.c:6129
ext4_dirty_inode+0xbf/0x100 fs/ext4/inode.c:6166
__mark_inode_dirty+0x2e7/0xe80 fs/fs-writeback.c:2515
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:6284
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: 0033:0x7f1203c6bae3
RSP: 002b:00007fffb084dad0 EFLAGS: 00010246
RAX: 00000000003ffde8 RBX: 0000000000000000 RCX: 0000001b2fa64000
RDX: 0000001b2fa24000 RSI: 0000000000400000 RDI: 00007f1203fe2708
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 00007fffb084dd60
Showing all locks held in the system:
4 locks held by kworker/u4:0/9:
#0: ffff888141a48138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#1: ffffc900000e7d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#2: ffff88814de080e0 (&type->s_umount_key#31){++++}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:415
#3: ffff88814de0ac18 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_writepages+0x213/0x2e70 fs/ext4/inode.c:2717
1 lock held by rcu_tasks_kthre/12:
#0: ffffffff8cb2e230 (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: ffffffff8cb2ea50 (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: ffffffff8cb2d8a0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
#0: ffffffff8cb2d8a0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
#0: ffffffff8cb2d8a0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6669
1 lock held by khugepaged/35:
#0: ffff8880755fea58 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock include/linux/mmap_lock.h:71 [inline]
#0: ffff8880755fea58 (&mm->mmap_lock){++++}-{3:3}, at: collapse_huge_page mm/khugepaged.c:1037 [inline]
#0: ffff8880755fea58 (&mm->mmap_lock){++++}-{3:3}, at: hpage_collapse_scan_pmd+0x1f68/0x57c0 mm/khugepaged.c:1295
2 locks held by syz-executor/4258:
#0: ffff88807d088158 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
#0: ffff88807d088158 (&mm->mmap_lock){++++}-{3:3}, at: get_mmap_lock_carefully mm/memory.c:5320 [inline]
#0: ffff88807d088158 (&mm->mmap_lock){++++}-{3:3}, at: lock_mm_and_find_vma+0x2e/0x2f0 mm/memory.c:5382
#1: ffff88814de08558 (sb_pagefaults){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1897 [inline]
#1: ffff88814de08558 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs.h:2001 [inline]
#1: ffff88814de08558 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x192/0x10d0 fs/ext4/inode.c:6283
2 locks held by getty/5812:
#0: ffff88802fa07098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
#1: ffffc9001cbb32f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x41e/0x1360 drivers/tty/n_tty.c:2198
2 locks held by syz-executor/13969:
#0: ffff88814de08460 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x3d/0x90 fs/namespace.c:402
#1: ffff88804786ca38 (&type->i_mutex_dir_key#3/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:799 [inline]
#1: ffff88804786ca38 (&type->i_mutex_dir_key#3/1){+.+.}-{3:3}, at: filename_create+0x20b/0x450 fs/namei.c:3927
3 locks held by syz.4.3238/14171:
#0: ffff8880779e7958 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
#0: ffff8880779e7958 (&mm->mmap_lock){++++}-{3:3}, at: get_mmap_lock_carefully mm/memory.c:5320 [inline]
#0: ffff8880779e7958 (&mm->mmap_lock){++++}-{3:3}, at: lock_mm_and_find_vma+0x2e/0x2f0 mm/memory.c:5382
#1: ffff88814de08558 (sb_pagefaults){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1897 [inline]
#1: ffff88814de08558 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs.h:2001 [inline]
#1: ffff88814de08558 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x192/0x10d0 fs/ext4/inode.c:6283
#2: ffff88814de0c990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x2014/0x2240 fs/jbd2/transaction.c:463
2 locks held by syz-executor/14188:
#0: ffff88814de08460 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x3d/0x90 fs/namespace.c:402
#1: ffff888074b99810 (&type->i_mutex_dir_key#3/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:799 [inline]
#1: ffff888074b99810 (&type->i_mutex_dir_key#3/1){+.+.}-{3:3}, at: filename_create+0x20b/0x450 fs/namei.c:3927
2 locks held by syz.8.3258/14237:
#0: ffff8880755fea58 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
#0: ffff8880755fea58 (&mm->mmap_lock){++++}-{3:3}, at: get_mmap_lock_carefully mm/memory.c:5320 [inline]
#0: ffff8880755fea58 (&mm->mmap_lock){++++}-{3:3}, at: lock_mm_and_find_vma+0x2e/0x2f0 mm/memory.c:5382
#1: ffff88814de08558 (sb_pagefaults){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1897 [inline]
#1: ffff88814de08558 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs.h:2001 [inline]
#1: ffff88814de08558 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x192/0x10d0 fs/ext4/inode.c:6283
=============================================
NMI backtrace for cpu 1
CPU: 1 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 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 4301 Comm: kworker/u4:5 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: events_unbound cfg80211_wiphy_work
RIP: 0010:debug_lockdep_rcu_enabled+0x25/0x30 kernel/rcu/update.c:281
Code: 00 cc cc 00 00 31 c0 83 3d e7 1a ed 03 00 74 1d 83 3d 72 4e ed 03 00 74 14 65 48 8b 0d 84 af ce 75 31 c0 83 b9 dc 0a 00 00 00 <0f> 94 c0 c3 00 00 cc cc 00 00 cc 48 8b 3c 24 e8 d7 fa ff ff 66 90
RSP: 0018:ffffc900040b7678 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffff88802b810000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc900040b7870 R08: dffffc0000000000 R09: 1ffffffff2166648
R10: dffffc0000000000 R11: fffffbfff2166649 R12: 1ffff92000816edc
R13: ffffffff89a9f1db R14: ffffc900040b77c0 R15: 000000000000004c
FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000056170bf47168 CR3: 000000000c88e000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
rcu_read_unlock include/linux/rcupdate.h:820 [inline]
ieee80211_bss_info_update+0x622/0xbf0 net/mac80211/scan.c:188
ieee80211_rx_bss_info net/mac80211/ibss.c:1120 [inline]
ieee80211_rx_mgmt_probe_beacon net/mac80211/ibss.c:1609 [inline]
ieee80211_ibss_rx_queued_mgmt+0x1931/0x2eb0 net/mac80211/ibss.c:1638
ieee80211_iface_process_skb net/mac80211/iface.c:1711 [inline]
ieee80211_iface_work+0x72c/0xc70 net/mac80211/iface.c:1765
cfg80211_wiphy_work+0x224/0x260 net/wireless/core.c:433
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