[v5.15] INFO: task hung in mpage_prepare_extent_to_map
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syzbot
Aug 4, 2026, 3:48:35 PM (8 days ago) Aug 4
to syzkaller...@googlegroups.com
Hello,
syzbot found the following issue on:
HEAD commit: 6e2fd6534337 Linux 5.15.213
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=14d5acc6580000
kernel config: https://syzkaller.appspot.com/x/.config?x=f161cbc9aef65db0
dashboard link: https://syzkaller.appspot.com/bug?extid=5f7fffb58718fd726add
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/d7b46606b13d/disk-6e2fd653.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/da120fdeb081/vmlinux-6e2fd653.xz
kernel image: https://storage.googleapis.com/syzbot-assets/3c2643457e3f/bzImage-6e2fd653.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+5f7fff...@syzkaller.appspotmail.com
INFO: task kworker/u4:2:154 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:2 state:D stack:21328 pid: 154 ppid: 2 flags:0x00004000
Workqueue: writeback wb_workfn (flush-8:0)
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11c3/0x4350 kernel/sched/core.c:6395
schedule+0x11b/0x1e0 kernel/sched/core.c:6478
io_schedule+0x7c/0xd0 kernel/sched/core.c:8503
wait_on_page_bit_common+0x8bf/0xeb0 mm/filemap.c:1356
wait_on_page_writeback+0x122/0x180 mm/page-writeback.c:2909
mpage_prepare_extent_to_map+0x80d/0x1080 fs/ext4/inode.c:2631
ext4_writepages+0x9bb/0x2d40 fs/ext4/inode.c:2785
do_writepages+0x493/0x700 mm/page-writeback.c:2386
__writeback_single_inode+0x153/0xda0 fs/fs-writeback.c:1657
writeback_sb_inodes+0xaaa/0x1750 fs/fs-writeback.c:1940
wb_writeback+0x44a/0xbc0 fs/fs-writeback.c:2114
wb_do_writeback fs/fs-writeback.c:2257 [inline]
wb_workfn+0x43a/0xf20 fs/fs-writeback.c:2298
process_one_work+0x867/0xff0 kernel/workqueue.c:2310
worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457
kthread+0x42e/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
</TASK>
INFO: task jbd2/sda1-8:3521 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:25872 pid: 3521 ppid: 2 flags:0x00004000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11c3/0x4350 kernel/sched/core.c:6395
schedule+0x11b/0x1e0 kernel/sched/core.c:6478
io_schedule+0x7c/0xd0 kernel/sched/core.c:8503
bit_wait_io+0xd/0xc0 kernel/sched/wait_bit.c:209
__wait_on_bit kernel/sched/wait_bit.c:49 [inline]
out_of_line_wait_on_bit+0x173/0x230 kernel/sched/wait_bit.c:64
wait_on_buffer include/linux/buffer_head.h:390 [inline]
jbd2_journal_commit_transaction+0x2f0b/0x5c30 fs/jbd2/commit.c:848
kjournald2+0x45a/0x900 fs/jbd2/journal.c:213
kthread+0x42e/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
</TASK>
INFO: task syz-executor:4174 blocked for more than 143 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: 4174 ppid: 4173 flags:0x00004002
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11c3/0x4350 kernel/sched/core.c:6395
schedule+0x11b/0x1e0 kernel/sched/core.c:6478
io_schedule+0x7c/0xd0 kernel/sched/core.c:8503
bit_wait_io+0xd/0xc0 kernel/sched/wait_bit.c:209
__wait_on_bit kernel/sched/wait_bit.c:49 [inline]
out_of_line_wait_on_bit+0x173/0x230 kernel/sched/wait_bit.c:64
wait_on_bit_io include/linux/wait_bit.h:101 [inline]
do_get_write_access+0x134/0xe40 fs/jbd2/transaction.c:1116
jbd2_journal_get_write_access+0x108/0x140 fs/jbd2/transaction.c:1251
__ext4_journal_get_write_access+0x24d/0x6e0 fs/ext4/ext4_jbd2.c:235
ext4_reserve_inode_write+0x203/0x2e0 fs/ext4/inode.c:5866
__ext4_mark_inode_dirty+0x136/0x6c0 fs/ext4/inode.c:6040
ext4_dirty_inode+0xbf/0x100 fs/ext4/inode.c:6077
__mark_inode_dirty+0x2c8/0xc90 fs/fs-writeback.c:2480
generic_update_time+0x1cd/0x1f0 fs/inode.c:1881
inode_update_time fs/inode.c:1894 [inline]
file_update_time+0x3c0/0x440 fs/inode.c:2083
ext4_page_mkwrite+0x1bc/0x1250 fs/ext4/inode.c:6195
do_page_mkwrite+0x168/0x3c0 mm/memory.c:2922
wp_page_shared+0x163/0x6c0 mm/memory.c:3259
handle_pte_fault mm/memory.c:4668 [inline]
__handle_mm_fault mm/memory.c:4785 [inline]
handle_mm_fault+0x1fbd/0x4440 mm/memory.c:4883
do_user_addr_fault+0x494/0xc90 arch/x86/mm/fault.c:1355
handle_page_fault arch/x86/mm/fault.c:1443 [inline]
exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1496
asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:606
RIP: 0033:0x7f1a8f93f627
RSP: 002b:00007ffd171e11e0 EFLAGS: 00010202
RAX: 00007f1a8daaf000 RBX: 00005555765c90f0 RCX: 0000000000000001
RDX: 0000000000001a85 RSI: 00005555765c9118 RDI: 0000000000000002
RBP: 00007ffd171e16e0 R08: 0000000000000087 R09: 00005555765c9120
R10: 0000000000000000 R11: 0000000000000202 R12: 00007ffd171e1520
R13: 00007ffd171e1310 R14: 585858582e7a7973 R15: 00007ffd171e1260
</TASK>
INFO: task syz.0.574:5756 blocked for more than 144 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.574 state:D stack:27696 pid: 5756 ppid: 4194 flags:0x00004004
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11c3/0x4350 kernel/sched/core.c:6395
schedule+0x11b/0x1e0 kernel/sched/core.c:6478
io_schedule+0x7c/0xd0 kernel/sched/core.c:8503
bit_wait_io+0xd/0xc0 kernel/sched/wait_bit.c:209
__wait_on_bit kernel/sched/wait_bit.c:49 [inline]
out_of_line_wait_on_bit+0x173/0x230 kernel/sched/wait_bit.c:64
wait_on_bit_io include/linux/wait_bit.h:101 [inline]
do_get_write_access+0x134/0xe40 fs/jbd2/transaction.c:1116
jbd2_journal_get_write_access+0x108/0x140 fs/jbd2/transaction.c:1251
__ext4_journal_get_write_access+0x24d/0x6e0 fs/ext4/ext4_jbd2.c:235
ext4_reserve_inode_write+0x203/0x2e0 fs/ext4/inode.c:5866
__ext4_mark_inode_dirty+0x136/0x6c0 fs/ext4/inode.c:6040
ext4_dirty_inode+0xbf/0x100 fs/ext4/inode.c:6077
__mark_inode_dirty+0x2c8/0xc90 fs/fs-writeback.c:2480
generic_update_time+0x1cd/0x1f0 fs/inode.c:1881
inode_update_time fs/inode.c:1894 [inline]
file_update_time+0x3c0/0x440 fs/inode.c:2083
ext4_page_mkwrite+0x1bc/0x1250 fs/ext4/inode.c:6195
do_page_mkwrite+0x168/0x3c0 mm/memory.c:2922
wp_page_shared+0x163/0x6c0 mm/memory.c:3259
handle_pte_fault mm/memory.c:4668 [inline]
__handle_mm_fault mm/memory.c:4785 [inline]
handle_mm_fault+0x1fbd/0x4440 mm/memory.c:4883
do_user_addr_fault+0x494/0xc90 arch/x86/mm/fault.c:1355
handle_page_fault arch/x86/mm/fault.c:1443 [inline]
exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1496
asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:606
RIP: 0033:0x7fbbbeda6806
RSP: 002b:00007ffc70f65530 EFLAGS: 00010202
RAX: 0000001b32623fc0 RBX: ffffffff815ebddb RCX: 0000000000000004
RDX: 0000001b3222421c RSI: 0000000000000004 RDI: 00007fbbbfc89720
RBP: 0000000000000000 R08: 00007fbbbf144000 R09: 00007fbbbf146000
R10: 00000000815ebddf R11: 0000000000000003 R12: 00007fbbbf15a038
R13: 0000000000002e6c R14: ffffffff815ebe99 R15: 00007fbbbfc89720
</TASK>
INFO: task syz.0.574:5757 blocked for more than 144 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.574 state:D stack:27760 pid: 5757 ppid: 4194 flags:0x00004004
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11c3/0x4350 kernel/sched/core.c:6395
schedule+0x11b/0x1e0 kernel/sched/core.c:6478
wb_wait_for_completion+0x171/0x290 fs/fs-writeback.c:191
sync_inodes_sb+0x1bd/0x950 fs/fs-writeback.c:2787
iterate_supers+0x11e/0x1d0 fs/super.c:718
ksys_sync+0x9d/0x170 fs/sync.c:102
ksys_sync_helper+0x13/0xa0 kernel/power/main.c:60
enter_state kernel/power/suspend.c:569 [inline]
pm_suspend+0x1b4/0x7c0 kernel/power/suspend.c:612
state_store+0x202/0x290 kernel/power/main.c:661
kernfs_fop_write_iter+0x3a8/0x500 fs/kernfs/file.c:296
call_write_iter include/linux/fs.h:2173 [inline]
new_sync_write fs/read_write.c:507 [inline]
vfs_write+0x748/0xd70 fs/read_write.c:594
ksys_write+0x153/0x260 fs/read_write.c:647
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fbbbeed2019
RSP: 002b:00007fbbbd12a028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fbbbf159fa0 RCX: 00007fbbbeed2019
RDX: 0000000000000004 RSI: 00002000000000c0 RDI: 0000000000000003
RBP: 00007fbbbef6900c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fbbbf15a038 R14: 00007fbbbf159fa0 R15: 00007ffc70f65498
</TASK>
INFO: task syz.4.585:5783 blocked for more than 144 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.585 state:D stack:27696 pid: 5783 ppid: 4189 flags:0x00004004
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11c3/0x4350 kernel/sched/core.c:6395
schedule+0x11b/0x1e0 kernel/sched/core.c:6478
io_schedule+0x7c/0xd0 kernel/sched/core.c:8503
bit_wait_io+0xd/0xc0 kernel/sched/wait_bit.c:209
__wait_on_bit kernel/sched/wait_bit.c:49 [inline]
out_of_line_wait_on_bit+0x173/0x230 kernel/sched/wait_bit.c:64
wait_on_bit_io include/linux/wait_bit.h:101 [inline]
do_get_write_access+0x134/0xe40 fs/jbd2/transaction.c:1116
jbd2_journal_get_write_access+0x108/0x140 fs/jbd2/transaction.c:1251
__ext4_journal_get_write_access+0x24d/0x6e0 fs/ext4/ext4_jbd2.c:235
ext4_reserve_inode_write+0x203/0x2e0 fs/ext4/inode.c:5866
__ext4_mark_inode_dirty+0x136/0x6c0 fs/ext4/inode.c:6040
ext4_dirty_inode+0xbf/0x100 fs/ext4/inode.c:6077
__mark_inode_dirty+0x2c8/0xc90 fs/fs-writeback.c:2480
generic_update_time+0x1cd/0x1f0 fs/inode.c:1881
inode_update_time fs/inode.c:1894 [inline]
file_update_time+0x3c0/0x440 fs/inode.c:2083
ext4_page_mkwrite+0x1bc/0x1250 fs/ext4/inode.c:6195
do_page_mkwrite+0x168/0x3c0 mm/memory.c:2922
do_shared_fault mm/memory.c:4328 [inline]
do_fault mm/memory.c:4396 [inline]
handle_pte_fault mm/memory.c:4650 [inline]
__handle_mm_fault mm/memory.c:4785 [inline]
handle_mm_fault+0x1e47/0x4440 mm/memory.c:4883
do_user_addr_fault+0x494/0xc90 arch/x86/mm/fault.c:1355
handle_page_fault arch/x86/mm/fault.c:1443 [inline]
exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1496
asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:606
RIP: 0033:0x7f41a01766d0
RSP: 002b:00007ffc1c6ff018 EFLAGS: 00010202
RAX: 0000001b32a20ff6 RBX: 00007f41a0f5b720 RCX: 0000000000000000
RDX: 000000000000000a RSI: 0000000000000000 RDI: 0000001b32a20ff6
RBP: 000000000000000a R08: 0000000000000008 R09: 00007f41a042c038
R10: 0000000000000003 R11: 0000000000000004 R12: 0000000000003000
R13: 0000000000002ff4 R14: 000000000000000a R15: 0000000000000000
</TASK>
INFO: task syz.3.586:5789 blocked for more than 145 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.586 state:D stack:27696 pid: 5789 ppid: 4188 flags:0x00004004
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11c3/0x4350 kernel/sched/core.c:6395
schedule+0x11b/0x1e0 kernel/sched/core.c:6478
io_schedule+0x7c/0xd0 kernel/sched/core.c:8503
bit_wait_io+0xd/0xc0 kernel/sched/wait_bit.c:209
__wait_on_bit kernel/sched/wait_bit.c:49 [inline]
out_of_line_wait_on_bit+0x173/0x230 kernel/sched/wait_bit.c:64
wait_on_bit_io include/linux/wait_bit.h:101 [inline]
do_get_write_access+0x134/0xe40 fs/jbd2/transaction.c:1116
jbd2_journal_get_write_access+0x108/0x140 fs/jbd2/transaction.c:1251
__ext4_journal_get_write_access+0x24d/0x6e0 fs/ext4/ext4_jbd2.c:235
ext4_reserve_inode_write+0x203/0x2e0 fs/ext4/inode.c:5866
__ext4_mark_inode_dirty+0x136/0x6c0 fs/ext4/inode.c:6040
ext4_dirty_inode+0xbf/0x100 fs/ext4/inode.c:6077
__mark_inode_dirty+0x2c8/0xc90 fs/fs-writeback.c:2480
generic_update_time+0x1cd/0x1f0 fs/inode.c:1881
inode_update_time fs/inode.c:1894 [inline]
file_update_time+0x3c0/0x440 fs/inode.c:2083
ext4_page_mkwrite+0x1bc/0x1250 fs/ext4/inode.c:6195
do_page_mkwrite+0x168/0x3c0 mm/memory.c:2922
do_shared_fault mm/memory.c:4328 [inline]
do_fault mm/memory.c:4396 [inline]
handle_pte_fault mm/memory.c:4650 [inline]
__handle_mm_fault mm/memory.c:4785 [inline]
handle_mm_fault+0x1e47/0x4440 mm/memory.c:4883
do_user_addr_fault+0x494/0xc90 arch/x86/mm/fault.c:1355
handle_page_fault arch/x86/mm/fault.c:1443 [inline]
exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1496
asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:606
RIP: 0033:0x7fa53f8119e3
RSP: 002b:00007fff5a352770 EFLAGS: 00010246
RAX: 00000000003ffde8 RBX: 0000000000000000 RCX: 0000001b32564000
RDX: 0000001b32524000 RSI: 0000000000400000 RDI: 00007fa53fb86708
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 00007fff5a352a00
</TASK>
Showing all locks held in the system:
4 locks held by kworker/1:1/26:
#0: ffff8880b913a358 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x25/0x130 kernel/sched/core.c:475
#1: ffff8880b9127888 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x4c3/0x810 kernel/sched/psi.c:882
#2: ffff8880b9127eb8 (krc.lock){..-.}-{2:2}, at: kfree_rcu_monitor+0x29/0x6e0 kernel/rcu/tree.c:3382
#3: ffffffff8c31ef60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:312
1 lock held by khungtaskd/27:
#0: ffffffff8c31ef60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
3 locks held by kworker/u4:2/154:
#0: ffff88801a7dc138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
#1: ffffc90001fc7d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
#2: ffff88802cfb0c58 (&sbi->s_writepages_rwsem){.+.+}-{0:0}, at: ext4_writepages+0x213/0x2d40 fs/ext4/inode.c:2691
1 lock held by klogd/3548:
#0: ffff8880b903a358 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x25/0x130 kernel/sched/core.c:475
2 locks held by getty/3949:
#0: ffff88802cdde098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
#1: ffffc90002cf62e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x594/0x1a50 drivers/tty/n_tty.c:2158
3 locks held by syz-executor/4174:
#0: ffff88807afe6a28 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
#0: ffff88807afe6a28 (&mm->mmap_lock){++++}-{3:3}, at: do_user_addr_fault+0x2bb/0xc90 arch/x86/mm/fault.c:1296
#1: ffff88802cfae558 (sb_pagefaults){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1811 [inline]
#1: ffff88802cfae558 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs.h:1910 [inline]
#1: ffff88802cfae558 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x1a5/0x1250 fs/ext4/inode.c:6194
#2: ffff88802cfb2990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x12d5/0x1560 fs/jbd2/transaction.c:462
3 locks held by syz.0.574/5756:
#0: ffff88807767f828 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
#0: ffff88807767f828 (&mm->mmap_lock){++++}-{3:3}, at: do_user_addr_fault+0x2bb/0xc90 arch/x86/mm/fault.c:1296
#1: ffff88802cfae558 (sb_pagefaults){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1811 [inline]
#1: ffff88802cfae558 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs.h:1910 [inline]
#1: ffff88802cfae558 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x1a5/0x1250 fs/ext4/inode.c:6194
#2: ffff88802cfb2990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x12d5/0x1560 fs/jbd2/transaction.c:462
7 locks held by syz.0.574/5757:
#0: ffff88807818b4f0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2bf/0x370 fs/file.c:1056
#1: ffff88805b650460 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x296/0xd70 fs/read_write.c:590
#2: ffff888060fefc88 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1dc/0x500 fs/kernfs/file.c:287
#3: ffff888144bffda0 (kn->active#387){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x1fd/0x500 fs/kernfs/file.c:288
#4: ffffffff8c1d7c68 (system_transition_mutex){+.+.}-{3:3}, at: enter_state kernel/power/suspend.c:561 [inline]
#4: ffffffff8c1d7c68 (system_transition_mutex){+.+.}-{3:3}, at: pm_suspend+0x31f/0x7c0 kernel/power/suspend.c:612
#5: ffff88802cfae0e0 (&type->s_umount_key#32){++++}-{3:3}, at: iterate_supers+0xa4/0x1d0 fs/super.c:716
#6: ffff888023c007d8 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:362 [inline]
#6: ffff888023c007d8 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0x1a1/0x950 fs/fs-writeback.c:2785
3 locks held by syz.4.585/5783:
#0: ffff88807e075c28 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
#0: ffff88807e075c28 (&mm->mmap_lock){++++}-{3:3}, at: do_user_addr_fault+0x2bb/0xc90 arch/x86/mm/fault.c:1296
#1: ffff88802cfae558 (sb_pagefaults){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1811 [inline]
#1: ffff88802cfae558 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs.h:1910 [inline]
#1: ffff88802cfae558 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x1a5/0x1250 fs/ext4/inode.c:6194
#2: ffff88802cfb2990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x12d5/0x1560 fs/jbd2/transaction.c:462
3 locks held by syz.3.586/5789:
#0: ffff88802c7f9628 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
#0: ffff88802c7f9628 (&mm->mmap_lock){++++}-{3:3}, at: do_user_addr_fault+0x2bb/0xc90 arch/x86/mm/fault.c:1296
#1: ffff88802cfae558 (sb_pagefaults){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1811 [inline]
#1: ffff88802cfae558 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs.h:1910 [inline]
#1: ffff88802cfae558 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x1a5/0x1250 fs/ext4/inode.c:6194
#2: ffff88802cfb2990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x12d5/0x1560 fs/jbd2/transaction.c:462
=============================================
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:
<TASK>
dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
nmi_cpu_backtrace+0x3a2/0x3d0 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline]
watchdog+0xe1b/0xe60 kernel/hung_task.c:369
kthread+0x42e/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
</TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 144 Comm: kworker/u4:1 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: bat_events batadv_nc_worker
RIP: 0010:debug_spin_lock_after kernel/locking/spinlock_debug.c:93 [inline]
RIP: 0010:do_raw_spin_lock+0x159/0x2f0 kernel/locking/spinlock_debug.c:117
Code: 00 00 f0 0f b1 0b 0f 85 1c 01 00 00 43 c6 44 34 04 f8 65 8b 1d 30 e6 a3 7e 43 0f b6 04 37 84 c0 0f 85 65 01 00 00 41 89 5d 00 <48> 8b 44 24 10 42 80 3c 30 00 48 8b 5c 24 18 74 12 48 89 df e8 9e
RSP: 0018:ffffc900016afa80 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000001
RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffc900016afac0
RBP: ffffc900016afb40 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff520002d5f58 R12: 1ffff920002d5f54
R13: ffff888019be0cc8 R14: dffffc0000000000 R15: 1ffff1100337c199
FS: 0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f69fa5be6c8 CR3: 000000002b6c3000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
spin_lock_bh include/linux/spinlock.h:369 [inline]
batadv_nc_purge_paths+0xe2/0x3a0 net/batman-adv/network-coding.c:446
batadv_nc_worker+0x321/0x5c0 net/batman-adv/network-coding.c:726
process_one_work+0x867/0xff0 kernel/workqueue.c:2310
worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457
kthread+0x42e/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
</TASK>
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title
If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)
If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report
If you want to undo deduplication, reply with:
#syz undup
syzbot found the following issue on:
HEAD commit: 6e2fd6534337 Linux 5.15.213
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=14d5acc6580000
kernel config: https://syzkaller.appspot.com/x/.config?x=f161cbc9aef65db0
dashboard link: https://syzkaller.appspot.com/bug?extid=5f7fffb58718fd726add
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/d7b46606b13d/disk-6e2fd653.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/da120fdeb081/vmlinux-6e2fd653.xz
kernel image: https://storage.googleapis.com/syzbot-assets/3c2643457e3f/bzImage-6e2fd653.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+5f7fff...@syzkaller.appspotmail.com
INFO: task kworker/u4:2:154 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:2 state:D stack:21328 pid: 154 ppid: 2 flags:0x00004000
Workqueue: writeback wb_workfn (flush-8:0)
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11c3/0x4350 kernel/sched/core.c:6395
schedule+0x11b/0x1e0 kernel/sched/core.c:6478
io_schedule+0x7c/0xd0 kernel/sched/core.c:8503
wait_on_page_bit_common+0x8bf/0xeb0 mm/filemap.c:1356
wait_on_page_writeback+0x122/0x180 mm/page-writeback.c:2909
mpage_prepare_extent_to_map+0x80d/0x1080 fs/ext4/inode.c:2631
ext4_writepages+0x9bb/0x2d40 fs/ext4/inode.c:2785
do_writepages+0x493/0x700 mm/page-writeback.c:2386
__writeback_single_inode+0x153/0xda0 fs/fs-writeback.c:1657
writeback_sb_inodes+0xaaa/0x1750 fs/fs-writeback.c:1940
wb_writeback+0x44a/0xbc0 fs/fs-writeback.c:2114
wb_do_writeback fs/fs-writeback.c:2257 [inline]
wb_workfn+0x43a/0xf20 fs/fs-writeback.c:2298
process_one_work+0x867/0xff0 kernel/workqueue.c:2310
worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457
kthread+0x42e/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
</TASK>
INFO: task jbd2/sda1-8:3521 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:25872 pid: 3521 ppid: 2 flags:0x00004000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11c3/0x4350 kernel/sched/core.c:6395
schedule+0x11b/0x1e0 kernel/sched/core.c:6478
io_schedule+0x7c/0xd0 kernel/sched/core.c:8503
bit_wait_io+0xd/0xc0 kernel/sched/wait_bit.c:209
__wait_on_bit kernel/sched/wait_bit.c:49 [inline]
out_of_line_wait_on_bit+0x173/0x230 kernel/sched/wait_bit.c:64
wait_on_buffer include/linux/buffer_head.h:390 [inline]
jbd2_journal_commit_transaction+0x2f0b/0x5c30 fs/jbd2/commit.c:848
kjournald2+0x45a/0x900 fs/jbd2/journal.c:213
kthread+0x42e/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
</TASK>
INFO: task syz-executor:4174 blocked for more than 143 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: 4174 ppid: 4173 flags:0x00004002
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11c3/0x4350 kernel/sched/core.c:6395
schedule+0x11b/0x1e0 kernel/sched/core.c:6478
io_schedule+0x7c/0xd0 kernel/sched/core.c:8503
bit_wait_io+0xd/0xc0 kernel/sched/wait_bit.c:209
__wait_on_bit kernel/sched/wait_bit.c:49 [inline]
out_of_line_wait_on_bit+0x173/0x230 kernel/sched/wait_bit.c:64
wait_on_bit_io include/linux/wait_bit.h:101 [inline]
do_get_write_access+0x134/0xe40 fs/jbd2/transaction.c:1116
jbd2_journal_get_write_access+0x108/0x140 fs/jbd2/transaction.c:1251
__ext4_journal_get_write_access+0x24d/0x6e0 fs/ext4/ext4_jbd2.c:235
ext4_reserve_inode_write+0x203/0x2e0 fs/ext4/inode.c:5866
__ext4_mark_inode_dirty+0x136/0x6c0 fs/ext4/inode.c:6040
ext4_dirty_inode+0xbf/0x100 fs/ext4/inode.c:6077
__mark_inode_dirty+0x2c8/0xc90 fs/fs-writeback.c:2480
generic_update_time+0x1cd/0x1f0 fs/inode.c:1881
inode_update_time fs/inode.c:1894 [inline]
file_update_time+0x3c0/0x440 fs/inode.c:2083
ext4_page_mkwrite+0x1bc/0x1250 fs/ext4/inode.c:6195
do_page_mkwrite+0x168/0x3c0 mm/memory.c:2922
wp_page_shared+0x163/0x6c0 mm/memory.c:3259
handle_pte_fault mm/memory.c:4668 [inline]
__handle_mm_fault mm/memory.c:4785 [inline]
handle_mm_fault+0x1fbd/0x4440 mm/memory.c:4883
do_user_addr_fault+0x494/0xc90 arch/x86/mm/fault.c:1355
handle_page_fault arch/x86/mm/fault.c:1443 [inline]
exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1496
asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:606
RIP: 0033:0x7f1a8f93f627
RSP: 002b:00007ffd171e11e0 EFLAGS: 00010202
RAX: 00007f1a8daaf000 RBX: 00005555765c90f0 RCX: 0000000000000001
RDX: 0000000000001a85 RSI: 00005555765c9118 RDI: 0000000000000002
RBP: 00007ffd171e16e0 R08: 0000000000000087 R09: 00005555765c9120
R10: 0000000000000000 R11: 0000000000000202 R12: 00007ffd171e1520
R13: 00007ffd171e1310 R14: 585858582e7a7973 R15: 00007ffd171e1260
</TASK>
INFO: task syz.0.574:5756 blocked for more than 144 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.574 state:D stack:27696 pid: 5756 ppid: 4194 flags:0x00004004
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11c3/0x4350 kernel/sched/core.c:6395
schedule+0x11b/0x1e0 kernel/sched/core.c:6478
io_schedule+0x7c/0xd0 kernel/sched/core.c:8503
bit_wait_io+0xd/0xc0 kernel/sched/wait_bit.c:209
__wait_on_bit kernel/sched/wait_bit.c:49 [inline]
out_of_line_wait_on_bit+0x173/0x230 kernel/sched/wait_bit.c:64
wait_on_bit_io include/linux/wait_bit.h:101 [inline]
do_get_write_access+0x134/0xe40 fs/jbd2/transaction.c:1116
jbd2_journal_get_write_access+0x108/0x140 fs/jbd2/transaction.c:1251
__ext4_journal_get_write_access+0x24d/0x6e0 fs/ext4/ext4_jbd2.c:235
ext4_reserve_inode_write+0x203/0x2e0 fs/ext4/inode.c:5866
__ext4_mark_inode_dirty+0x136/0x6c0 fs/ext4/inode.c:6040
ext4_dirty_inode+0xbf/0x100 fs/ext4/inode.c:6077
__mark_inode_dirty+0x2c8/0xc90 fs/fs-writeback.c:2480
generic_update_time+0x1cd/0x1f0 fs/inode.c:1881
inode_update_time fs/inode.c:1894 [inline]
file_update_time+0x3c0/0x440 fs/inode.c:2083
ext4_page_mkwrite+0x1bc/0x1250 fs/ext4/inode.c:6195
do_page_mkwrite+0x168/0x3c0 mm/memory.c:2922
wp_page_shared+0x163/0x6c0 mm/memory.c:3259
handle_pte_fault mm/memory.c:4668 [inline]
__handle_mm_fault mm/memory.c:4785 [inline]
handle_mm_fault+0x1fbd/0x4440 mm/memory.c:4883
do_user_addr_fault+0x494/0xc90 arch/x86/mm/fault.c:1355
handle_page_fault arch/x86/mm/fault.c:1443 [inline]
exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1496
asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:606
RIP: 0033:0x7fbbbeda6806
RSP: 002b:00007ffc70f65530 EFLAGS: 00010202
RAX: 0000001b32623fc0 RBX: ffffffff815ebddb RCX: 0000000000000004
RDX: 0000001b3222421c RSI: 0000000000000004 RDI: 00007fbbbfc89720
RBP: 0000000000000000 R08: 00007fbbbf144000 R09: 00007fbbbf146000
R10: 00000000815ebddf R11: 0000000000000003 R12: 00007fbbbf15a038
R13: 0000000000002e6c R14: ffffffff815ebe99 R15: 00007fbbbfc89720
</TASK>
INFO: task syz.0.574:5757 blocked for more than 144 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.574 state:D stack:27760 pid: 5757 ppid: 4194 flags:0x00004004
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11c3/0x4350 kernel/sched/core.c:6395
schedule+0x11b/0x1e0 kernel/sched/core.c:6478
wb_wait_for_completion+0x171/0x290 fs/fs-writeback.c:191
sync_inodes_sb+0x1bd/0x950 fs/fs-writeback.c:2787
iterate_supers+0x11e/0x1d0 fs/super.c:718
ksys_sync+0x9d/0x170 fs/sync.c:102
ksys_sync_helper+0x13/0xa0 kernel/power/main.c:60
enter_state kernel/power/suspend.c:569 [inline]
pm_suspend+0x1b4/0x7c0 kernel/power/suspend.c:612
state_store+0x202/0x290 kernel/power/main.c:661
kernfs_fop_write_iter+0x3a8/0x500 fs/kernfs/file.c:296
call_write_iter include/linux/fs.h:2173 [inline]
new_sync_write fs/read_write.c:507 [inline]
vfs_write+0x748/0xd70 fs/read_write.c:594
ksys_write+0x153/0x260 fs/read_write.c:647
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fbbbeed2019
RSP: 002b:00007fbbbd12a028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fbbbf159fa0 RCX: 00007fbbbeed2019
RDX: 0000000000000004 RSI: 00002000000000c0 RDI: 0000000000000003
RBP: 00007fbbbef6900c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fbbbf15a038 R14: 00007fbbbf159fa0 R15: 00007ffc70f65498
</TASK>
INFO: task syz.4.585:5783 blocked for more than 144 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.585 state:D stack:27696 pid: 5783 ppid: 4189 flags:0x00004004
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11c3/0x4350 kernel/sched/core.c:6395
schedule+0x11b/0x1e0 kernel/sched/core.c:6478
io_schedule+0x7c/0xd0 kernel/sched/core.c:8503
bit_wait_io+0xd/0xc0 kernel/sched/wait_bit.c:209
__wait_on_bit kernel/sched/wait_bit.c:49 [inline]
out_of_line_wait_on_bit+0x173/0x230 kernel/sched/wait_bit.c:64
wait_on_bit_io include/linux/wait_bit.h:101 [inline]
do_get_write_access+0x134/0xe40 fs/jbd2/transaction.c:1116
jbd2_journal_get_write_access+0x108/0x140 fs/jbd2/transaction.c:1251
__ext4_journal_get_write_access+0x24d/0x6e0 fs/ext4/ext4_jbd2.c:235
ext4_reserve_inode_write+0x203/0x2e0 fs/ext4/inode.c:5866
__ext4_mark_inode_dirty+0x136/0x6c0 fs/ext4/inode.c:6040
ext4_dirty_inode+0xbf/0x100 fs/ext4/inode.c:6077
__mark_inode_dirty+0x2c8/0xc90 fs/fs-writeback.c:2480
generic_update_time+0x1cd/0x1f0 fs/inode.c:1881
inode_update_time fs/inode.c:1894 [inline]
file_update_time+0x3c0/0x440 fs/inode.c:2083
ext4_page_mkwrite+0x1bc/0x1250 fs/ext4/inode.c:6195
do_page_mkwrite+0x168/0x3c0 mm/memory.c:2922
do_shared_fault mm/memory.c:4328 [inline]
do_fault mm/memory.c:4396 [inline]
handle_pte_fault mm/memory.c:4650 [inline]
__handle_mm_fault mm/memory.c:4785 [inline]
handle_mm_fault+0x1e47/0x4440 mm/memory.c:4883
do_user_addr_fault+0x494/0xc90 arch/x86/mm/fault.c:1355
handle_page_fault arch/x86/mm/fault.c:1443 [inline]
exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1496
asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:606
RIP: 0033:0x7f41a01766d0
RSP: 002b:00007ffc1c6ff018 EFLAGS: 00010202
RAX: 0000001b32a20ff6 RBX: 00007f41a0f5b720 RCX: 0000000000000000
RDX: 000000000000000a RSI: 0000000000000000 RDI: 0000001b32a20ff6
RBP: 000000000000000a R08: 0000000000000008 R09: 00007f41a042c038
R10: 0000000000000003 R11: 0000000000000004 R12: 0000000000003000
R13: 0000000000002ff4 R14: 000000000000000a R15: 0000000000000000
</TASK>
INFO: task syz.3.586:5789 blocked for more than 145 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.586 state:D stack:27696 pid: 5789 ppid: 4188 flags:0x00004004
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11c3/0x4350 kernel/sched/core.c:6395
schedule+0x11b/0x1e0 kernel/sched/core.c:6478
io_schedule+0x7c/0xd0 kernel/sched/core.c:8503
bit_wait_io+0xd/0xc0 kernel/sched/wait_bit.c:209
__wait_on_bit kernel/sched/wait_bit.c:49 [inline]
out_of_line_wait_on_bit+0x173/0x230 kernel/sched/wait_bit.c:64
wait_on_bit_io include/linux/wait_bit.h:101 [inline]
do_get_write_access+0x134/0xe40 fs/jbd2/transaction.c:1116
jbd2_journal_get_write_access+0x108/0x140 fs/jbd2/transaction.c:1251
__ext4_journal_get_write_access+0x24d/0x6e0 fs/ext4/ext4_jbd2.c:235
ext4_reserve_inode_write+0x203/0x2e0 fs/ext4/inode.c:5866
__ext4_mark_inode_dirty+0x136/0x6c0 fs/ext4/inode.c:6040
ext4_dirty_inode+0xbf/0x100 fs/ext4/inode.c:6077
__mark_inode_dirty+0x2c8/0xc90 fs/fs-writeback.c:2480
generic_update_time+0x1cd/0x1f0 fs/inode.c:1881
inode_update_time fs/inode.c:1894 [inline]
file_update_time+0x3c0/0x440 fs/inode.c:2083
ext4_page_mkwrite+0x1bc/0x1250 fs/ext4/inode.c:6195
do_page_mkwrite+0x168/0x3c0 mm/memory.c:2922
do_shared_fault mm/memory.c:4328 [inline]
do_fault mm/memory.c:4396 [inline]
handle_pte_fault mm/memory.c:4650 [inline]
__handle_mm_fault mm/memory.c:4785 [inline]
handle_mm_fault+0x1e47/0x4440 mm/memory.c:4883
do_user_addr_fault+0x494/0xc90 arch/x86/mm/fault.c:1355
handle_page_fault arch/x86/mm/fault.c:1443 [inline]
exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1496
asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:606
RIP: 0033:0x7fa53f8119e3
RSP: 002b:00007fff5a352770 EFLAGS: 00010246
RAX: 00000000003ffde8 RBX: 0000000000000000 RCX: 0000001b32564000
RDX: 0000001b32524000 RSI: 0000000000400000 RDI: 00007fa53fb86708
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 00007fff5a352a00
</TASK>
Showing all locks held in the system:
4 locks held by kworker/1:1/26:
#0: ffff8880b913a358 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x25/0x130 kernel/sched/core.c:475
#1: ffff8880b9127888 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x4c3/0x810 kernel/sched/psi.c:882
#2: ffff8880b9127eb8 (krc.lock){..-.}-{2:2}, at: kfree_rcu_monitor+0x29/0x6e0 kernel/rcu/tree.c:3382
#3: ffffffff8c31ef60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:312
1 lock held by khungtaskd/27:
#0: ffffffff8c31ef60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
3 locks held by kworker/u4:2/154:
#0: ffff88801a7dc138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
#1: ffffc90001fc7d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
#2: ffff88802cfb0c58 (&sbi->s_writepages_rwsem){.+.+}-{0:0}, at: ext4_writepages+0x213/0x2d40 fs/ext4/inode.c:2691
1 lock held by klogd/3548:
#0: ffff8880b903a358 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x25/0x130 kernel/sched/core.c:475
2 locks held by getty/3949:
#0: ffff88802cdde098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
#1: ffffc90002cf62e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x594/0x1a50 drivers/tty/n_tty.c:2158
3 locks held by syz-executor/4174:
#0: ffff88807afe6a28 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
#0: ffff88807afe6a28 (&mm->mmap_lock){++++}-{3:3}, at: do_user_addr_fault+0x2bb/0xc90 arch/x86/mm/fault.c:1296
#1: ffff88802cfae558 (sb_pagefaults){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1811 [inline]
#1: ffff88802cfae558 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs.h:1910 [inline]
#1: ffff88802cfae558 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x1a5/0x1250 fs/ext4/inode.c:6194
#2: ffff88802cfb2990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x12d5/0x1560 fs/jbd2/transaction.c:462
3 locks held by syz.0.574/5756:
#0: ffff88807767f828 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
#0: ffff88807767f828 (&mm->mmap_lock){++++}-{3:3}, at: do_user_addr_fault+0x2bb/0xc90 arch/x86/mm/fault.c:1296
#1: ffff88802cfae558 (sb_pagefaults){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1811 [inline]
#1: ffff88802cfae558 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs.h:1910 [inline]
#1: ffff88802cfae558 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x1a5/0x1250 fs/ext4/inode.c:6194
#2: ffff88802cfb2990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x12d5/0x1560 fs/jbd2/transaction.c:462
7 locks held by syz.0.574/5757:
#0: ffff88807818b4f0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2bf/0x370 fs/file.c:1056
#1: ffff88805b650460 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x296/0xd70 fs/read_write.c:590
#2: ffff888060fefc88 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1dc/0x500 fs/kernfs/file.c:287
#3: ffff888144bffda0 (kn->active#387){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x1fd/0x500 fs/kernfs/file.c:288
#4: ffffffff8c1d7c68 (system_transition_mutex){+.+.}-{3:3}, at: enter_state kernel/power/suspend.c:561 [inline]
#4: ffffffff8c1d7c68 (system_transition_mutex){+.+.}-{3:3}, at: pm_suspend+0x31f/0x7c0 kernel/power/suspend.c:612
#5: ffff88802cfae0e0 (&type->s_umount_key#32){++++}-{3:3}, at: iterate_supers+0xa4/0x1d0 fs/super.c:716
#6: ffff888023c007d8 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:362 [inline]
#6: ffff888023c007d8 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0x1a1/0x950 fs/fs-writeback.c:2785
3 locks held by syz.4.585/5783:
#0: ffff88807e075c28 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
#0: ffff88807e075c28 (&mm->mmap_lock){++++}-{3:3}, at: do_user_addr_fault+0x2bb/0xc90 arch/x86/mm/fault.c:1296
#1: ffff88802cfae558 (sb_pagefaults){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1811 [inline]
#1: ffff88802cfae558 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs.h:1910 [inline]
#1: ffff88802cfae558 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x1a5/0x1250 fs/ext4/inode.c:6194
#2: ffff88802cfb2990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x12d5/0x1560 fs/jbd2/transaction.c:462
3 locks held by syz.3.586/5789:
#0: ffff88802c7f9628 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
#0: ffff88802c7f9628 (&mm->mmap_lock){++++}-{3:3}, at: do_user_addr_fault+0x2bb/0xc90 arch/x86/mm/fault.c:1296
#1: ffff88802cfae558 (sb_pagefaults){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1811 [inline]
#1: ffff88802cfae558 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs.h:1910 [inline]
#1: ffff88802cfae558 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x1a5/0x1250 fs/ext4/inode.c:6194
#2: ffff88802cfb2990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x12d5/0x1560 fs/jbd2/transaction.c:462
=============================================
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:
<TASK>
dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
nmi_cpu_backtrace+0x3a2/0x3d0 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline]
watchdog+0xe1b/0xe60 kernel/hung_task.c:369
kthread+0x42e/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
</TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 144 Comm: kworker/u4:1 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: bat_events batadv_nc_worker
RIP: 0010:debug_spin_lock_after kernel/locking/spinlock_debug.c:93 [inline]
RIP: 0010:do_raw_spin_lock+0x159/0x2f0 kernel/locking/spinlock_debug.c:117
Code: 00 00 f0 0f b1 0b 0f 85 1c 01 00 00 43 c6 44 34 04 f8 65 8b 1d 30 e6 a3 7e 43 0f b6 04 37 84 c0 0f 85 65 01 00 00 41 89 5d 00 <48> 8b 44 24 10 42 80 3c 30 00 48 8b 5c 24 18 74 12 48 89 df e8 9e
RSP: 0018:ffffc900016afa80 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000001
RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffc900016afac0
RBP: ffffc900016afb40 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff520002d5f58 R12: 1ffff920002d5f54
R13: ffff888019be0cc8 R14: dffffc0000000000 R15: 1ffff1100337c199
FS: 0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f69fa5be6c8 CR3: 000000002b6c3000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
spin_lock_bh include/linux/spinlock.h:369 [inline]
batadv_nc_purge_paths+0xe2/0x3a0 net/batman-adv/network-coding.c:446
batadv_nc_worker+0x321/0x5c0 net/batman-adv/network-coding.c:726
process_one_work+0x867/0xff0 kernel/workqueue.c:2310
worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457
kthread+0x42e/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
</TASK>
---
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