Hello,
syzbot found the following issue on:
HEAD commit: aabd761612db Linux 5.15.215
git tree: linux-5.15.y
console output:
https://syzkaller.appspot.com/x/log.txt?x=1258e2c6580000
kernel config:
https://syzkaller.appspot.com/x/.config?x=f161cbc9aef65db0
dashboard link:
https://syzkaller.appspot.com/bug?extid=5372ea9b426367b39933
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/f636f56d3662/disk-aabd7616.raw.xz
vmlinux:
https://storage.googleapis.com/syzbot-assets/f1a46620f40c/vmlinux-aabd7616.xz
kernel image:
https://storage.googleapis.com/syzbot-assets/9b78bb48b022/bzImage-aabd7616.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by:
syzbot+5372ea...@syzkaller.appspotmail.com
INFO: task kworker/u4:1:144 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:1 state:D stack:21264 pid: 144 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
rq_qos_wait+0x21d/0x330 block/blk-rq-qos.c:288
__wbt_wait block/blk-wbt.c:522 [inline]
wbt_wait+0x39e/0x680 block/blk-wbt.c:586
__rq_qos_throttle+0x61/0xa0 block/blk-rq-qos.c:72
rq_qos_throttle block/blk-rq-qos.h:203 [inline]
blk_mq_submit_bio+0x434/0x1950 block/blk-mq.c:2233
__submit_bio+0x73e/0x780 block/blk-core.c:917
__submit_bio_noacct_mq block/blk-core.c:997 [inline]
submit_bio_noacct+0x6b1/0x800 block/blk-core.c:1027
submit_bio+0x2c6/0x550 block/blk-core.c:1089
ext4_io_submit+0x14a/0x200 fs/ext4/page-io.c:381
ext4_writepages+0x9d5/0x2d40 fs/ext4/inode.c:2789
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
__writeback_inodes_wb+0x12a/0x3f0 fs/fs-writeback.c:2011
wb_writeback+0x45e/0xbc0 fs/fs-writeback.c:2116
wb_check_old_data_flush fs/fs-writeback.c:2216 [inline]
wb_do_writeback fs/fs-writeback.c:2269 [inline]
wb_workfn+0xb15/0xf20 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 144 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:jbd2/sda1-8 state:D stack:25392 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 145 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor state:D stack:23344 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: 0033:0x7f32ba937662
RSP: 002b:00007fffad847060 EFLAGS: 00010246
RAX: 00007f32b894b000 RBX: 000055556e372d60 RCX: 0000000000000000
RDX: 0000000000000878 RSI: 000055556e37f3a8 RDI: 0000000000000001
RBP: 00007fffad847560 R08: 000055556e37f3a8 R09: 0000000000000087
R10: 0000000000000000 R11: 0000000000000202 R12: 00007fffad8473a0
R13: 00007fffad847190 R14: 585858582e7a7973 R15: 00007fffad8470e0
</TASK>
INFO: task syz.6.1609:11805 blocked for more than 146 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.6.1609 state:D stack:27696 pid:11805 ppid: 7589 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: 0033:0x7f431d927729
RSP: 002b:00007ffca0cff7a0 EFLAGS: 00010202
RAX: 0000001b2e923000 RBX: ffffffff81c6b598 RCX: 0000001b2e922ff8
RDX: 0000001b2e524220 RSI: 0000000000000008 RDI: 00007f431e80a720
RBP: 00000000000001e7 R08: 00007f431dcc5000 R09: 00007f431dcc7000
R10: 0000000081c6b59c R11: 000000000000000b R12: 00007f431dcdb128
R13: 000000000000056a R14: ffffffff81c6b954 R15: 00007f431e80a720
</TASK>
INFO: task syz.9.1612:11820 blocked for more than 147 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.9.1612 state:D stack:27696 pid:11820 ppid: 10434 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: 0033:0x7f9a77d79729
RSP: 002b:00007ffd10de66d0 EFLAGS: 00010202
RAX: 0000001b30e23000 RBX: ffffffff888ac6d8 RCX: 0000001b30e22ff8
RDX: 0000001b30a24220 RSI: 0000000000000008 RDI: 00007f9a78c5c720
RBP: 00000000000001ef R08: 00007f9a78117000 R09: 00007f9a78119000
R10: 00000000888ac6dc R11: 0000000000000008 R12: 00007f9a7812d128
R13: 0000000000000824 R14: ffffffff888acf43 R15: 00007f9a78c5c720
</TASK>
INFO: task syz.8.1613:11834 blocked for more than 148 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.8.1613 state:D stack:27696 pid:11834 ppid: 9281 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: 0033:0x7f96fc762a23
RSP: 002b:00007ffc4f060f50 EFLAGS: 00010246
RAX: 00000000005ffde8 RBX: 0000000000000000 RCX: 0000001b30064000
RDX: 0000001b30024000 RSI: 0000000000600000 RDI: 00007f96fcad7708
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 00007ffc4f0611e0
</TASK>
INFO: task syz.5.1614:11842 blocked for more than 149 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.5.1614 state:D stack:27696 pid:11842 ppid: 7497 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: 0033:0x7f40b3c2ba23
RSP: 002b:00007ffe9ab80990 EFLAGS: 00010246
RAX: 00000000003ffde8 RBX: 0000000000000000 RCX: 0000001b31164000
RDX: 0000001b31124000 RSI: 0000000000400000 RDI: 00007f40b3fa0708
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 00007ffe9ab80c20
</TASK>
Showing all locks held in the system:
1 lock held by khungtaskd/27:
#0: ffffffff8c31ef60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
4 locks held by kworker/u4:1/144:
#0: ffff888142bf0138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
#1: ffffc9000162fd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
#2: ffff88814d4e80e0 (&type->s_umount_key#32){++++}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418
#3: ffff88814d4eac58 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_writepages+0x213/0x2d40 fs/ext4/inode.c:2691
1 lock held by dhcpcd/3852:
#0: ffff8880279e2d38 (&iint_mutex_key[depth]){+.+.}-{3:3}, at: process_measurement+0x724/0x1c20 security/integrity/ima/ima_main.c:261
2 locks held by getty/3951:
#0: ffff88802bf76098 (&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: ffff88807abf1628 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
#0: ffff88807abf1628 (&mm->mmap_lock){++++}-{3:3}, at: do_user_addr_fault+0x2bb/0xc90 arch/x86/mm/fault.c:1296
#1: ffff88814d4e8558 (sb_pagefaults){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1811 [inline]
#1: ffff88814d4e8558 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs.h:1910 [inline]
#1: ffff88814d4e8558 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x1a5/0x1250 fs/ext4/inode.c:6194
#2: ffff88814d4ec990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x12d5/0x1560 fs/jbd2/transaction.c:462
3 locks held by syz.6.1609/11805:
#0: ffff88802bfc5528 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
#0: ffff88802bfc5528 (&mm->mmap_lock){++++}-{3:3}, at: do_user_addr_fault+0x2bb/0xc90 arch/x86/mm/fault.c:1296
#1: ffff88814d4e8558 (sb_pagefaults){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1811 [inline]
#1: ffff88814d4e8558 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs.h:1910 [inline]
#1: ffff88814d4e8558 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x1a5/0x1250 fs/ext4/inode.c:6194
#2: ffff88814d4ec990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x12d5/0x1560 fs/jbd2/transaction.c:462
3 locks held by syz.9.1612/11820:
#0: ffff88807e057128 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
#0: ffff88807e057128 (&mm->mmap_lock){++++}-{3:3}, at: do_user_addr_fault+0x2bb/0xc90 arch/x86/mm/fault.c:1296
#1: ffff88814d4e8558 (sb_pagefaults){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1811 [inline]
#1: ffff88814d4e8558 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs.h:1910 [inline]
#1: ffff88814d4e8558 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x1a5/0x1250 fs/ext4/inode.c:6194
#2: ffff88814d4ec990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x12d5/0x1560 fs/jbd2/transaction.c:462
3 locks held by syz.8.1613/11834:
#0: ffff88807dc3dc28 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
#0: ffff88807dc3dc28 (&mm->mmap_lock){++++}-{3:3}, at: do_user_addr_fault+0x2bb/0xc90 arch/x86/mm/fault.c:1296
#1: ffff88814d4e8558 (sb_pagefaults){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1811 [inline]
#1: ffff88814d4e8558 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs.h:1910 [inline]
#1: ffff88814d4e8558 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x1a5/0x1250 fs/ext4/inode.c:6194
#2: ffff88814d4ec990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x12d5/0x1560 fs/jbd2/transaction.c:462
3 locks held by syz.5.1614/11842:
#0: ffff88802b030f28 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
#0: ffff88802b030f28 (&mm->mmap_lock){++++}-{3:3}, at: do_user_addr_fault+0x2bb/0xc90 arch/x86/mm/fault.c:1296
#1: ffff88814d4e8558 (sb_pagefaults){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1811 [inline]
#1: ffff88814d4e8558 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs.h:1910 [inline]
#1: ffff88814d4e8558 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x1a5/0x1250 fs/ext4/inode.c:6194
#2: ffff88814d4ec990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x12d5/0x1560 fs/jbd2/transaction.c:462
=============================================
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:
<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>
---
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#syz fix: exact-commit-title