[syzbot] [ext4?] INFO: task hung in ext4_write_end
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syzbot
Jul 2, 2026, 2:06:32 AM (yesterday) Jul 2
to adilger...@dilger.ca, ja...@suse.cz, liba...@linux.alibaba.com, linux...@vger.kernel.org, linux-...@vger.kernel.org, oja...@linux.ibm.com, rites...@gmail.com, syzkall...@googlegroups.com, ty...@mit.edu, yi.z...@huawei.com
Hello,
syzbot found the following issue on:
HEAD commit: 665159e24674 Merge tag 'probes-fixes-v7.2-rc1' of git://gi..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12a54ae0580000
kernel config: https://syzkaller.appspot.com/x/.config?x=86ba763b42fa66a
dashboard link: https://syzkaller.appspot.com/bug?extid=16bf7cd0ebeb1de93aa5
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11804946580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/a05a33a56982/disk-665159e2.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/155ad8e180de/vmlinux-665159e2.xz
kernel image: https://storage.googleapis.com/syzbot-assets/40c3a5216293/bzImage-665159e2.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/62f6b0a820df/mount_0.gz
fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=126fce51580000)
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+16bf7c...@syzkaller.appspotmail.com
INFO: task syz.0.297:7222 blocked in I/O wait for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.297 state:D stack:24616 pid:7222 tgid:7218 ppid:5781 task_flags:0x400140 flags:0x00080002
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x17d9/0x56c0 kernel/sched/core.c:7234
__schedule_loop kernel/sched/core.c:7311 [inline]
schedule+0x164/0x2b0 kernel/sched/core.c:7326
io_schedule+0x7f/0xd0 kernel/sched/core.c:8154
folio_wait_bit_common+0x836/0xbc0 mm/filemap.c:1323
folio_lock include/linux/pagemap.h:1157 [inline]
truncate_inode_pages_range+0xa41/0xd80 mm/truncate.c:458
ext4_truncate_failed_write fs/ext4/truncate.h:21 [inline]
ext4_write_end+0x734/0x9e0 fs/ext4/inode.c:1495
generic_perform_write+0x612/0x8f0 mm/filemap.c:4379
ext4_buffered_write_iter+0xcb/0x370 fs/ext4/file.c:316
ext4_file_write_iter+0x947/0x1c70 fs/ext4/file.c:-1
new_sync_write fs/read_write.c:595 [inline]
vfs_write+0x612/0xba0 fs/read_write.c:687
ksys_write+0x150/0x270 fs/read_write.c:739
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f395cf9de59
RSP: 002b:00007f395dde8028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f395d225fa0 RCX: 00007f395cf9de59
RDX: 000000000000fea7 RSI: 0000200000000180 RDI: 0000000000000005
RBP: 00007f395d033e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f395d226038 R14: 00007f395d225fa0 R15: 00007ffff725c4c8
</TASK>
INFO: task syz.0.297:7244 blocked for more than 144 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.297 state:D stack:23760 pid:7244 tgid:7218 ppid:5781 task_flags:0x440040 flags:0x00080002
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x17d9/0x56c0 kernel/sched/core.c:7234
__schedule_loop kernel/sched/core.c:7311 [inline]
schedule+0x164/0x2b0 kernel/sched/core.c:7326
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7383
rwsem_down_read_slowpath+0x6ba/0x920 kernel/locking/rwsem.c:1114
__down_read_common kernel/locking/rwsem.c:1291 [inline]
__down_read kernel/locking/rwsem.c:1304 [inline]
down_read+0x9c/0x330 kernel/locking/rwsem.c:1576
filemap_invalidate_lock_shared include/linux/fs.h:1089 [inline]
page_cache_ra_order+0x3eb/0xee0 mm/readahead.c:517
page_cache_sync_readahead include/linux/pagemap.h:1395 [inline]
collapse_file mm/khugepaged.c:2335 [inline]
collapse_scan_file+0x1ab9/0x5210 mm/khugepaged.c:2773
collapse_single_pmd+0x2b1/0x3da0 mm/khugepaged.c:2808
madvise_collapse+0x2cf/0x790 mm/khugepaged.c:3234
madvise_vma_behavior+0x11ac/0x42e0 mm/madvise.c:1364
madvise_walk_vmas+0x576/0xb00 mm/madvise.c:1713
madvise_do_behavior+0x385/0x540 mm/madvise.c:1908
do_madvise+0x327/0x3a0 mm/madvise.c:2006
__do_sys_madvise mm/madvise.c:2015 [inline]
__se_sys_madvise mm/madvise.c:2013 [inline]
__x64_sys_madvise+0xa6/0xc0 mm/madvise.c:2013
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f395cf9de59
RSP: 002b:00007f395ddc7028 EFLAGS: 00000246 ORIG_RAX: 000000000000001c
RAX: ffffffffffffffda RBX: 00007f395d226090 RCX: 00007f395cf9de59
RDX: 0000000000000019 RSI: 0000000000600000 RDI: 0000200000000000
RBP: 00007f395d033e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f395d226128 R14: 00007f395d226090 R15: 00007ffff725c4c8
</TASK>
INFO: task syz.4.326:7346 blocked in I/O wait for more than 146 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.326 state:D stack:24616 pid:7346 tgid:7345 ppid:5806 task_flags:0x400140 flags:0x00080002
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x17d9/0x56c0 kernel/sched/core.c:7234
__schedule_loop kernel/sched/core.c:7311 [inline]
schedule+0x164/0x2b0 kernel/sched/core.c:7326
io_schedule+0x7f/0xd0 kernel/sched/core.c:8154
folio_wait_bit_common+0x836/0xbc0 mm/filemap.c:1323
folio_lock include/linux/pagemap.h:1157 [inline]
truncate_inode_pages_range+0xa41/0xd80 mm/truncate.c:458
ext4_truncate_failed_write fs/ext4/truncate.h:21 [inline]
ext4_write_end+0x734/0x9e0 fs/ext4/inode.c:1495
generic_perform_write+0x612/0x8f0 mm/filemap.c:4379
ext4_buffered_write_iter+0xcb/0x370 fs/ext4/file.c:316
ext4_file_write_iter+0x947/0x1c70 fs/ext4/file.c:-1
new_sync_write fs/read_write.c:595 [inline]
vfs_write+0x612/0xba0 fs/read_write.c:687
ksys_write+0x150/0x270 fs/read_write.c:739
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7efe9399de59
RSP: 002b:00007efe94897028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007efe93c25fa0 RCX: 00007efe9399de59
RDX: 000000000000fea7 RSI: 0000200000000180 RDI: 0000000000000005
RBP: 00007efe93a33e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007efe93c26038 R14: 00007efe93c25fa0 R15: 00007fff4570fa28
</TASK>
INFO: task syz.4.326:7360 blocked for more than 147 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.326 state:D stack:23696 pid:7360 tgid:7345 ppid:5806 task_flags:0x440040 flags:0x00080002
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x17d9/0x56c0 kernel/sched/core.c:7234
__schedule_loop kernel/sched/core.c:7311 [inline]
schedule+0x164/0x2b0 kernel/sched/core.c:7326
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7383
rwsem_down_read_slowpath+0x6ba/0x920 kernel/locking/rwsem.c:1114
__down_read_common kernel/locking/rwsem.c:1291 [inline]
__down_read kernel/locking/rwsem.c:1304 [inline]
down_read+0x9c/0x330 kernel/locking/rwsem.c:1576
filemap_invalidate_lock_shared include/linux/fs.h:1089 [inline]
page_cache_ra_order+0x3eb/0xee0 mm/readahead.c:517
page_cache_sync_readahead include/linux/pagemap.h:1395 [inline]
collapse_file mm/khugepaged.c:2335 [inline]
collapse_scan_file+0x1ab9/0x5210 mm/khugepaged.c:2773
collapse_single_pmd+0x2b1/0x3da0 mm/khugepaged.c:2808
madvise_collapse+0x2cf/0x790 mm/khugepaged.c:3234
madvise_vma_behavior+0x11ac/0x42e0 mm/madvise.c:1364
madvise_walk_vmas+0x576/0xb00 mm/madvise.c:1713
madvise_do_behavior+0x385/0x540 mm/madvise.c:1908
do_madvise+0x327/0x3a0 mm/madvise.c:2006
__do_sys_madvise mm/madvise.c:2015 [inline]
__se_sys_madvise mm/madvise.c:2013 [inline]
__x64_sys_madvise+0xa6/0xc0 mm/madvise.c:2013
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7efe9399de59
RSP: 002b:00007efe94876028 EFLAGS: 00000246 ORIG_RAX: 000000000000001c
RAX: ffffffffffffffda RBX: 00007efe93c26090 RCX: 00007efe9399de59
RDX: 0000000000000019 RSI: 0000000000600000 RDI: 0000200000000000
RBP: 00007efe93a33e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007efe93c26128 R14: 00007efe93c26090 R15: 00007fff4570fa28
</TASK>
Showing all locks held in the system:
1 lock held by khungtaskd/32:
#0: ffffffff8e959c20 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8e959c20 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#0: ffffffff8e959c20 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
3 locks held by kworker/u8:2/37:
4 locks held by kworker/u8:8/1341:
#0: ffff88801ae8c140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
#0: ffff88801ae8c140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
#1: ffffc90006187c40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
#1: ffffc90006187c40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
#2: ffffffff8fdecec0 (
rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:313
#3: ffffffff8e95ff28 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:311 [inline]
#3: ffffffff8e95ff28 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2d0/0x770 kernel/rcu/tree_exp.h:961
1 lock held by udevd/4987:
2 locks held by getty/5372:
#0: ffff888035a570a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc900032332e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360 drivers/tty/n_tty.c:2211
1 lock held by udevd/5670:
4 locks held by syz.0.297/7222:
#0: ffff88807063f430 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x246/0x320 fs/file.c:1259
#1: ffff888020ecc450 (sb_writers#4){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2728 [inline]
#1: ffff888020ecc450 (sb_writers#4){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683
#2: ffff88806e84d7e0 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline]
#2: ffff88806e84d7e0 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: ext4_buffered_write_iter+0x9c/0x370 fs/ext4/file.c:311
#3: ffff88806e84d978 (mapping.invalidate_lock#2){++++}-{4:4}, at: filemap_invalidate_lock include/linux/fs.h:1079 [inline]
#3: ffff88806e84d978 (mapping.invalidate_lock#2){++++}-{4:4}, at: ext4_truncate_failed_write fs/ext4/truncate.h:20 [inline]
#3: ffff88806e84d978 (mapping.invalidate_lock#2){++++}-{4:4}, at: ext4_write_end+0x713/0x9e0 fs/ext4/inode.c:1495
1 lock held by syz.0.297/7244:
#0: ffff88806e84d978 (mapping.invalidate_lock#2){++++}-{4:4}, at: filemap_invalidate_lock_shared include/linux/fs.h:1089 [inline]
#0: ffff88806e84d978 (mapping.invalidate_lock#2){++++}-{4:4}, at: page_cache_ra_order+0x3eb/0xee0 mm/readahead.c:517
4 locks held by syz.4.326/7346:
#0: ffff888021b287f0 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x246/0x320 fs/file.c:1259
#1: ffff888020782450 (sb_writers#4){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2728 [inline]
#1: ffff888020782450 (sb_writers#4){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683
#2: ffff88806ea39640 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline]
#2: ffff88806ea39640 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: ext4_buffered_write_iter+0x9c/0x370 fs/ext4/file.c:311
#3: ffff88806ea397d8 (mapping.invalidate_lock#2){++++}-{4:4}, at: filemap_invalidate_lock include/linux/fs.h:1079 [inline]
#3: ffff88806ea397d8 (mapping.invalidate_lock#2){++++}-{4:4}, at: ext4_truncate_failed_write fs/ext4/truncate.h:20 [inline]
#3: ffff88806ea397d8 (mapping.invalidate_lock#2){++++}-{4:4}, at: ext4_write_end+0x713/0x9e0 fs/ext4/inode.c:1495
1 lock held by syz.4.326/7360:
#0: ffff88806ea397d8 (mapping.invalidate_lock#2){++++}-{4:4}, at: filemap_invalidate_lock_shared include/linux/fs.h:1089 [inline]
#0: ffff88806ea397d8 (mapping.invalidate_lock#2){++++}-{4:4}, at: page_cache_ra_order+0x3eb/0xee0 mm/readahead.c:517
4 locks held by syz.7.867/9690:
#0: ffff88807e5e97b0 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x246/0x320 fs/file.c:1259
#1: ffff888058692450 (sb_writers#4){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2728 [inline]
#1: ffff888058692450 (sb_writers#4){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683
#2: ffff88805586e140 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline]
#2: ffff88805586e140 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: ext4_buffered_write_iter+0x9c/0x370 fs/ext4/file.c:311
#3: ffff88805586e2d8 (mapping.invalidate_lock#2){++++}-{4:4}, at: filemap_invalidate_lock include/linux/fs.h:1079 [inline]
#3: ffff88805586e2d8 (mapping.invalidate_lock#2){++++}-{4:4}, at: ext4_truncate_failed_write fs/ext4/truncate.h:20 [inline]
#3: ffff88805586e2d8 (mapping.invalidate_lock#2){++++}-{4:4}, at: ext4_write_end+0x713/0x9e0 fs/ext4/inode.c:1495
1 lock held by syz.7.867/9704:
#0: ffff88805586e2d8 (mapping.invalidate_lock#2){++++}-{4:4}, at: filemap_invalidate_lock_shared include/linux/fs.h:1089 [inline]
#0: ffff88805586e2d8 (mapping.invalidate_lock#2){++++}-{4:4}, at: page_cache_ra_order+0x3eb/0xee0 mm/readahead.c:517
4 locks held by syz.3.1163/10927:
#0: ffff88807ec65270 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x246/0x320 fs/file.c:1259
#1: ffff888059256450 (sb_writers#4){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2728 [inline]
#1: ffff888059256450 (sb_writers#4){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683
#2: ffff888055a1c520 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline]
#2: ffff888055a1c520 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: ext4_buffered_write_iter+0x9c/0x370 fs/ext4/file.c:311
#3: ffff888055a1c6b8 (mapping.invalidate_lock#2){++++}-{4:4}, at: filemap_invalidate_lock include/linux/fs.h:1079 [inline]
#3: ffff888055a1c6b8 (mapping.invalidate_lock#2){++++}-{4:4}, at: ext4_truncate_failed_write fs/ext4/truncate.h:20 [inline]
#3: ffff888055a1c6b8 (mapping.invalidate_lock#2){++++}-{4:4}, at: ext4_write_end+0x713/0x9e0 fs/ext4/inode.c:1495
1 lock held by syz.3.1163/10946:
#0: ffff888055a1c6b8 (mapping.invalidate_lock#2){++++}-{4:4}, at: filemap_invalidate_lock_shared include/linux/fs.h:1089 [inline]
#0: ffff888055a1c6b8 (mapping.invalidate_lock#2){++++}-{4:4}, at: page_cache_ra_order+0x3eb/0xee0 mm/readahead.c:517
4 locks held by syz.5.1177/10998:
#0: ffff88807748fcf0 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x246/0x320 fs/file.c:1259
#1: ffff888056ee6450 (sb_writers#4){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2728 [inline]
#1: ffff888056ee6450 (sb_writers#4){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683
#2: ffff888076ccd7e0 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline]
#2: ffff888076ccd7e0 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: ext4_buffered_write_iter+0x9c/0x370 fs/ext4/file.c:311
#3: ffff888076ccd978 (mapping.invalidate_lock#2){++++}-{4:4}, at: filemap_invalidate_lock include/linux/fs.h:1079 [inline]
#3: ffff888076ccd978 (mapping.invalidate_lock#2){++++}-{4:4}, at: ext4_truncate_failed_write fs/ext4/truncate.h:20 [inline]
#3: ffff888076ccd978 (mapping.invalidate_lock#2){++++}-{4:4}, at: ext4_write_end+0x713/0x9e0 fs/ext4/inode.c:1495
1 lock held by syz.5.1177/11014:
#0: ffff888076ccd978 (mapping.invalidate_lock#2){++++}-{4:4}, at: filemap_invalidate_lock_shared include/linux/fs.h:1089 [inline]
#0: ffff888076ccd978 (mapping.invalidate_lock#2){++++}-{4:4}, at: page_cache_ra_order+0x3eb/0xee0 mm/readahead.c:517
4 locks held by syz.8.1536/12449:
#0: ffff8880339f1cf0 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x246/0x320 fs/file.c:1259
#1: ffff88807b69a450 (sb_writers#4){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2728 [inline]
#1: ffff88807b69a450 (sb_writers#4){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683
#2: ffff888076c8ce80 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline]
#2: ffff888076c8ce80 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: ext4_buffered_write_iter+0x9c/0x370 fs/ext4/file.c:311
#3: ffff888076c8d018 (mapping.invalidate_lock#2){++++}-{4:4}, at: filemap_invalidate_lock include/linux/fs.h:1079 [inline]
#3: ffff888076c8d018 (mapping.invalidate_lock#2){++++}-{4:4}, at: ext4_truncate_failed_write fs/ext4/truncate.h:20 [inline]
#3: ffff888076c8d018 (mapping.invalidate_lock#2){++++}-{4:4}, at: ext4_write_end+0x713/0x9e0 fs/ext4/inode.c:1495
1 lock held by syz.8.1536/12465:
#0: ffff888076c8d018 (mapping.invalidate_lock#2){++++}-{4:4}, at: filemap_invalidate_lock_shared include/linux/fs.h:1089 [inline]
#0: ffff888076c8d018 (mapping.invalidate_lock#2){++++}-{4:4}, at: page_cache_ra_order+0x3eb/0xee0 mm/readahead.c:517
4 locks held by syz.6.1557/12517:
#0: ffff88807b6eeb70 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x246/0x320 fs/file.c:1259
#1: ffff888057e82450 (sb_writers#4){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2728 [inline]
#1: ffff888057e82450 (sb_writers#4){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683
#2: ffff88806eabd7e0 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline]
#2: ffff88806eabd7e0 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: ext4_buffered_write_iter+0x9c/0x370 fs/ext4/file.c:311
#3: ffff88806eabd978 (mapping.invalidate_lock#2){++++}-{4:4}, at: filemap_invalidate_lock include/linux/fs.h:1079 [inline]
#3: ffff88806eabd978 (mapping.invalidate_lock#2){++++}-{4:4}, at: ext4_truncate_failed_write fs/ext4/truncate.h:20 [inline]
#3: ffff88806eabd978 (mapping.invalidate_lock#2){++++}-{4:4}, at: ext4_write_end+0x713/0x9e0 fs/ext4/inode.c:1495
1 lock held by syz.6.1557/12533:
#0: ffff88806eabd978 (mapping.invalidate_lock#2){++++}-{4:4}, at: filemap_invalidate_lock_shared include/linux/fs.h:1089 [inline]
#0: ffff88806eabd978 (mapping.invalidate_lock#2){++++}-{4:4}, at: page_cache_ra_order+0x3eb/0xee0 mm/readahead.c:517
1 lock held by syz-executor/13000:
#0: ffffffff8fdecec0 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
#0: ffffffff8fdecec0 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
#0: ffffffff8fdecec0 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8a3/0x1bd0 net/core/rtnetlink.c:4158
2 locks held by syz-executor/13036:
#0: ffffffff8fdde328 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x4e2/0x720 net/core/net_namespace.c:575
#1: ffffffff8fdecec0 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock_killable include/linux/rtnetlink.h:145 [inline]
#1: ffffffff8fdecec0 (rtnl_mutex){+.+.}-{4:4}, at: register_netdev+0x18/0x60 net/core/dev.c:11553
2 locks held by dhcpcd/13097:
#0: ffff888058895880 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline]
#0: ffff888058895880 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: __sock_release net/socket.c:709 [inline]
#0: ffff888058895880 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: sock_close+0x82/0x220 net/socket.c:1501
#1: ffffffff8e95ff28 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:343 [inline]
#1: ffffffff8e95ff28 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x38d/0x770 kernel/rcu/tree_exp.h:961
1 lock held by dhcpcd/13113:
#0: ffff888070c80260 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1713 [inline]
#0: ffff888070c80260 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x33/0xe90 net/packet/af_packet.c:3204
1 lock held by dhcpcd/13127:
#0: ffff888079e76260 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1713 [inline]
#0: ffff888079e76260 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x33/0xe90 net/packet/af_packet.c:3204
3 locks held by syz.0.1755/13140:
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 32 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Call Trace:
<TASK>
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:122
nmi_trigger_cpumask_backtrace+0x17a/0x380 lib/nmi_backtrace.c:65
trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
__sys_info lib/sys_info.c:157 [inline]
sys_info+0x135/0x170 lib/sys_info.c:165
check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline]
watchdog+0xfd7/0x1030 kernel/hung_task.c:561
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 11424 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:io_serial_in+0x77/0xc0 drivers/tty/serial/8250/8250_port.c:401
Code: e8 de 15 7a fc 44 89 f9 d3 e3 49 83 c6 40 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 4f 9a e7 fc 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f e9 f5 f4 c3 fb cc 44 89 f9 80 e1 07
RSP: 0018:ffffc9000396f5a8 EFLAGS: 00000002
RAX: 1ffffffff3501500 RBX: 00000000000003fd RCX: 0000000000000000
RDX: 00000000000003fd RSI: 0000000000000000 RDI: 0000000000000020
RBP: dffffc0000000000 R08: ffff8880264f0237 R09: 1ffff11004c9e046
R10: dffffc0000000000 R11: ffffffff854c4b90 R12: dffffc0000000000
R13: 0000000000000000 R14: ffffffff9a80ae80 R15: 0000000000000000
FS: 000055558b7f8500(0000) GS:ffff888125320000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000010000 CR3: 000000002cc76000 CR4: 0000000000350ef0
Call Trace:
<TASK>
serial_in drivers/tty/serial/8250/8250.h:128 [inline]
serial_lsr_in drivers/tty/serial/8250/8250.h:150 [inline]
wait_for_lsr+0x184/0x2f0 drivers/tty/serial/8250/8250_port.c:1982
serial8250_fifo_wait_for_lsr_thre drivers/tty/serial/8250/8250_port.c:3229 [inline]
serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3294 [inline]
serial8250_console_write+0x12ef/0x1ba0 drivers/tty/serial/8250/8250_port.c:3379
console_emit_next_record kernel/printk/printk.c:3183 [inline]
console_flush_one_record kernel/printk/printk.c:3269 [inline]
console_flush_all+0x6ea/0xaf0 kernel/printk/printk.c:3343
__console_flush_and_unlock kernel/printk/printk.c:3373 [inline]
console_unlock+0xd1/0x1c0 kernel/printk/printk.c:3413
vprintk_emit+0x485/0x560 kernel/printk/printk.c:2479
_printk+0xdd/0x130 kernel/printk/printk.c:2504
__ext4_msg+0x2b9/0x2d0 fs/ext4/super.c:1001
ext4_put_super+0xb6/0xd80 fs/ext4/super.c:1302
generic_shutdown_super+0x13d/0x2d0 fs/super.c:647
kill_block_super+0x44/0x90 fs/super.c:1665
ext4_kill_sb+0x68/0xb0 fs/ext4/super.c:7499
deactivate_locked_super+0xbc/0x130 fs/super.c:477
cleanup_mnt+0x3d3/0x460 fs/namespace.c:1317
task_work_run+0x1d9/0x270 kernel/task_work.c:233
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
__exit_to_user_mode_loop kernel/entry/common.c:70 [inline]
exit_to_user_mode_loop+0x1fa/0x730 kernel/entry/common.c:101
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
do_syscall_64+0x353/0x580 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8ab759f097
Code: a2 c7 05 5c 26 25 00 00 00 00 00 eb 96 e8 e1 12 00 00 90 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007fffcf334e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f8ab76332ca RCX: 00007f8ab759f097
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007fffcf334f20
RBP: 00007fffcf334f20 R08: 00007fffcf335f20 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fffcf335fb0
R13: 00007f8ab76332ca R14: 000000000005b196 R15: 00007fffcf335ff0
</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 syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.
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: 665159e24674 Merge tag 'probes-fixes-v7.2-rc1' of git://gi..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12a54ae0580000
kernel config: https://syzkaller.appspot.com/x/.config?x=86ba763b42fa66a
dashboard link: https://syzkaller.appspot.com/bug?extid=16bf7cd0ebeb1de93aa5
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11804946580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/a05a33a56982/disk-665159e2.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/155ad8e180de/vmlinux-665159e2.xz
kernel image: https://storage.googleapis.com/syzbot-assets/40c3a5216293/bzImage-665159e2.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/62f6b0a820df/mount_0.gz
fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=126fce51580000)
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+16bf7c...@syzkaller.appspotmail.com
INFO: task syz.0.297:7222 blocked in I/O wait for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.297 state:D stack:24616 pid:7222 tgid:7218 ppid:5781 task_flags:0x400140 flags:0x00080002
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x17d9/0x56c0 kernel/sched/core.c:7234
__schedule_loop kernel/sched/core.c:7311 [inline]
schedule+0x164/0x2b0 kernel/sched/core.c:7326
io_schedule+0x7f/0xd0 kernel/sched/core.c:8154
folio_wait_bit_common+0x836/0xbc0 mm/filemap.c:1323
folio_lock include/linux/pagemap.h:1157 [inline]
truncate_inode_pages_range+0xa41/0xd80 mm/truncate.c:458
ext4_truncate_failed_write fs/ext4/truncate.h:21 [inline]
ext4_write_end+0x734/0x9e0 fs/ext4/inode.c:1495
generic_perform_write+0x612/0x8f0 mm/filemap.c:4379
ext4_buffered_write_iter+0xcb/0x370 fs/ext4/file.c:316
ext4_file_write_iter+0x947/0x1c70 fs/ext4/file.c:-1
new_sync_write fs/read_write.c:595 [inline]
vfs_write+0x612/0xba0 fs/read_write.c:687
ksys_write+0x150/0x270 fs/read_write.c:739
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f395cf9de59
RSP: 002b:00007f395dde8028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f395d225fa0 RCX: 00007f395cf9de59
RDX: 000000000000fea7 RSI: 0000200000000180 RDI: 0000000000000005
RBP: 00007f395d033e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f395d226038 R14: 00007f395d225fa0 R15: 00007ffff725c4c8
</TASK>
INFO: task syz.0.297:7244 blocked for more than 144 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.297 state:D stack:23760 pid:7244 tgid:7218 ppid:5781 task_flags:0x440040 flags:0x00080002
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x17d9/0x56c0 kernel/sched/core.c:7234
__schedule_loop kernel/sched/core.c:7311 [inline]
schedule+0x164/0x2b0 kernel/sched/core.c:7326
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7383
rwsem_down_read_slowpath+0x6ba/0x920 kernel/locking/rwsem.c:1114
__down_read_common kernel/locking/rwsem.c:1291 [inline]
__down_read kernel/locking/rwsem.c:1304 [inline]
down_read+0x9c/0x330 kernel/locking/rwsem.c:1576
filemap_invalidate_lock_shared include/linux/fs.h:1089 [inline]
page_cache_ra_order+0x3eb/0xee0 mm/readahead.c:517
page_cache_sync_readahead include/linux/pagemap.h:1395 [inline]
collapse_file mm/khugepaged.c:2335 [inline]
collapse_scan_file+0x1ab9/0x5210 mm/khugepaged.c:2773
collapse_single_pmd+0x2b1/0x3da0 mm/khugepaged.c:2808
madvise_collapse+0x2cf/0x790 mm/khugepaged.c:3234
madvise_vma_behavior+0x11ac/0x42e0 mm/madvise.c:1364
madvise_walk_vmas+0x576/0xb00 mm/madvise.c:1713
madvise_do_behavior+0x385/0x540 mm/madvise.c:1908
do_madvise+0x327/0x3a0 mm/madvise.c:2006
__do_sys_madvise mm/madvise.c:2015 [inline]
__se_sys_madvise mm/madvise.c:2013 [inline]
__x64_sys_madvise+0xa6/0xc0 mm/madvise.c:2013
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f395cf9de59
RSP: 002b:00007f395ddc7028 EFLAGS: 00000246 ORIG_RAX: 000000000000001c
RAX: ffffffffffffffda RBX: 00007f395d226090 RCX: 00007f395cf9de59
RDX: 0000000000000019 RSI: 0000000000600000 RDI: 0000200000000000
RBP: 00007f395d033e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f395d226128 R14: 00007f395d226090 R15: 00007ffff725c4c8
</TASK>
INFO: task syz.4.326:7346 blocked in I/O wait for more than 146 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.326 state:D stack:24616 pid:7346 tgid:7345 ppid:5806 task_flags:0x400140 flags:0x00080002
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x17d9/0x56c0 kernel/sched/core.c:7234
__schedule_loop kernel/sched/core.c:7311 [inline]
schedule+0x164/0x2b0 kernel/sched/core.c:7326
io_schedule+0x7f/0xd0 kernel/sched/core.c:8154
folio_wait_bit_common+0x836/0xbc0 mm/filemap.c:1323
folio_lock include/linux/pagemap.h:1157 [inline]
truncate_inode_pages_range+0xa41/0xd80 mm/truncate.c:458
ext4_truncate_failed_write fs/ext4/truncate.h:21 [inline]
ext4_write_end+0x734/0x9e0 fs/ext4/inode.c:1495
generic_perform_write+0x612/0x8f0 mm/filemap.c:4379
ext4_buffered_write_iter+0xcb/0x370 fs/ext4/file.c:316
ext4_file_write_iter+0x947/0x1c70 fs/ext4/file.c:-1
new_sync_write fs/read_write.c:595 [inline]
vfs_write+0x612/0xba0 fs/read_write.c:687
ksys_write+0x150/0x270 fs/read_write.c:739
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7efe9399de59
RSP: 002b:00007efe94897028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007efe93c25fa0 RCX: 00007efe9399de59
RDX: 000000000000fea7 RSI: 0000200000000180 RDI: 0000000000000005
RBP: 00007efe93a33e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007efe93c26038 R14: 00007efe93c25fa0 R15: 00007fff4570fa28
</TASK>
INFO: task syz.4.326:7360 blocked for more than 147 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.326 state:D stack:23696 pid:7360 tgid:7345 ppid:5806 task_flags:0x440040 flags:0x00080002
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x17d9/0x56c0 kernel/sched/core.c:7234
__schedule_loop kernel/sched/core.c:7311 [inline]
schedule+0x164/0x2b0 kernel/sched/core.c:7326
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7383
rwsem_down_read_slowpath+0x6ba/0x920 kernel/locking/rwsem.c:1114
__down_read_common kernel/locking/rwsem.c:1291 [inline]
__down_read kernel/locking/rwsem.c:1304 [inline]
down_read+0x9c/0x330 kernel/locking/rwsem.c:1576
filemap_invalidate_lock_shared include/linux/fs.h:1089 [inline]
page_cache_ra_order+0x3eb/0xee0 mm/readahead.c:517
page_cache_sync_readahead include/linux/pagemap.h:1395 [inline]
collapse_file mm/khugepaged.c:2335 [inline]
collapse_scan_file+0x1ab9/0x5210 mm/khugepaged.c:2773
collapse_single_pmd+0x2b1/0x3da0 mm/khugepaged.c:2808
madvise_collapse+0x2cf/0x790 mm/khugepaged.c:3234
madvise_vma_behavior+0x11ac/0x42e0 mm/madvise.c:1364
madvise_walk_vmas+0x576/0xb00 mm/madvise.c:1713
madvise_do_behavior+0x385/0x540 mm/madvise.c:1908
do_madvise+0x327/0x3a0 mm/madvise.c:2006
__do_sys_madvise mm/madvise.c:2015 [inline]
__se_sys_madvise mm/madvise.c:2013 [inline]
__x64_sys_madvise+0xa6/0xc0 mm/madvise.c:2013
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7efe9399de59
RSP: 002b:00007efe94876028 EFLAGS: 00000246 ORIG_RAX: 000000000000001c
RAX: ffffffffffffffda RBX: 00007efe93c26090 RCX: 00007efe9399de59
RDX: 0000000000000019 RSI: 0000000000600000 RDI: 0000200000000000
RBP: 00007efe93a33e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007efe93c26128 R14: 00007efe93c26090 R15: 00007fff4570fa28
</TASK>
Showing all locks held in the system:
1 lock held by khungtaskd/32:
#0: ffffffff8e959c20 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8e959c20 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#0: ffffffff8e959c20 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
3 locks held by kworker/u8:2/37:
4 locks held by kworker/u8:8/1341:
#0: ffff88801ae8c140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
#0: ffff88801ae8c140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
#1: ffffc90006187c40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
#1: ffffc90006187c40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
#2: ffffffff8fdecec0 (
rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:313
#3: ffffffff8e95ff28 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:311 [inline]
#3: ffffffff8e95ff28 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2d0/0x770 kernel/rcu/tree_exp.h:961
1 lock held by udevd/4987:
2 locks held by getty/5372:
#0: ffff888035a570a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc900032332e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360 drivers/tty/n_tty.c:2211
1 lock held by udevd/5670:
4 locks held by syz.0.297/7222:
#0: ffff88807063f430 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x246/0x320 fs/file.c:1259
#1: ffff888020ecc450 (sb_writers#4){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2728 [inline]
#1: ffff888020ecc450 (sb_writers#4){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683
#2: ffff88806e84d7e0 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline]
#2: ffff88806e84d7e0 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: ext4_buffered_write_iter+0x9c/0x370 fs/ext4/file.c:311
#3: ffff88806e84d978 (mapping.invalidate_lock#2){++++}-{4:4}, at: filemap_invalidate_lock include/linux/fs.h:1079 [inline]
#3: ffff88806e84d978 (mapping.invalidate_lock#2){++++}-{4:4}, at: ext4_truncate_failed_write fs/ext4/truncate.h:20 [inline]
#3: ffff88806e84d978 (mapping.invalidate_lock#2){++++}-{4:4}, at: ext4_write_end+0x713/0x9e0 fs/ext4/inode.c:1495
1 lock held by syz.0.297/7244:
#0: ffff88806e84d978 (mapping.invalidate_lock#2){++++}-{4:4}, at: filemap_invalidate_lock_shared include/linux/fs.h:1089 [inline]
#0: ffff88806e84d978 (mapping.invalidate_lock#2){++++}-{4:4}, at: page_cache_ra_order+0x3eb/0xee0 mm/readahead.c:517
4 locks held by syz.4.326/7346:
#0: ffff888021b287f0 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x246/0x320 fs/file.c:1259
#1: ffff888020782450 (sb_writers#4){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2728 [inline]
#1: ffff888020782450 (sb_writers#4){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683
#2: ffff88806ea39640 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline]
#2: ffff88806ea39640 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: ext4_buffered_write_iter+0x9c/0x370 fs/ext4/file.c:311
#3: ffff88806ea397d8 (mapping.invalidate_lock#2){++++}-{4:4}, at: filemap_invalidate_lock include/linux/fs.h:1079 [inline]
#3: ffff88806ea397d8 (mapping.invalidate_lock#2){++++}-{4:4}, at: ext4_truncate_failed_write fs/ext4/truncate.h:20 [inline]
#3: ffff88806ea397d8 (mapping.invalidate_lock#2){++++}-{4:4}, at: ext4_write_end+0x713/0x9e0 fs/ext4/inode.c:1495
1 lock held by syz.4.326/7360:
#0: ffff88806ea397d8 (mapping.invalidate_lock#2){++++}-{4:4}, at: filemap_invalidate_lock_shared include/linux/fs.h:1089 [inline]
#0: ffff88806ea397d8 (mapping.invalidate_lock#2){++++}-{4:4}, at: page_cache_ra_order+0x3eb/0xee0 mm/readahead.c:517
4 locks held by syz.7.867/9690:
#0: ffff88807e5e97b0 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x246/0x320 fs/file.c:1259
#1: ffff888058692450 (sb_writers#4){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2728 [inline]
#1: ffff888058692450 (sb_writers#4){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683
#2: ffff88805586e140 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline]
#2: ffff88805586e140 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: ext4_buffered_write_iter+0x9c/0x370 fs/ext4/file.c:311
#3: ffff88805586e2d8 (mapping.invalidate_lock#2){++++}-{4:4}, at: filemap_invalidate_lock include/linux/fs.h:1079 [inline]
#3: ffff88805586e2d8 (mapping.invalidate_lock#2){++++}-{4:4}, at: ext4_truncate_failed_write fs/ext4/truncate.h:20 [inline]
#3: ffff88805586e2d8 (mapping.invalidate_lock#2){++++}-{4:4}, at: ext4_write_end+0x713/0x9e0 fs/ext4/inode.c:1495
1 lock held by syz.7.867/9704:
#0: ffff88805586e2d8 (mapping.invalidate_lock#2){++++}-{4:4}, at: filemap_invalidate_lock_shared include/linux/fs.h:1089 [inline]
#0: ffff88805586e2d8 (mapping.invalidate_lock#2){++++}-{4:4}, at: page_cache_ra_order+0x3eb/0xee0 mm/readahead.c:517
4 locks held by syz.3.1163/10927:
#0: ffff88807ec65270 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x246/0x320 fs/file.c:1259
#1: ffff888059256450 (sb_writers#4){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2728 [inline]
#1: ffff888059256450 (sb_writers#4){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683
#2: ffff888055a1c520 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline]
#2: ffff888055a1c520 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: ext4_buffered_write_iter+0x9c/0x370 fs/ext4/file.c:311
#3: ffff888055a1c6b8 (mapping.invalidate_lock#2){++++}-{4:4}, at: filemap_invalidate_lock include/linux/fs.h:1079 [inline]
#3: ffff888055a1c6b8 (mapping.invalidate_lock#2){++++}-{4:4}, at: ext4_truncate_failed_write fs/ext4/truncate.h:20 [inline]
#3: ffff888055a1c6b8 (mapping.invalidate_lock#2){++++}-{4:4}, at: ext4_write_end+0x713/0x9e0 fs/ext4/inode.c:1495
1 lock held by syz.3.1163/10946:
#0: ffff888055a1c6b8 (mapping.invalidate_lock#2){++++}-{4:4}, at: filemap_invalidate_lock_shared include/linux/fs.h:1089 [inline]
#0: ffff888055a1c6b8 (mapping.invalidate_lock#2){++++}-{4:4}, at: page_cache_ra_order+0x3eb/0xee0 mm/readahead.c:517
4 locks held by syz.5.1177/10998:
#0: ffff88807748fcf0 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x246/0x320 fs/file.c:1259
#1: ffff888056ee6450 (sb_writers#4){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2728 [inline]
#1: ffff888056ee6450 (sb_writers#4){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683
#2: ffff888076ccd7e0 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline]
#2: ffff888076ccd7e0 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: ext4_buffered_write_iter+0x9c/0x370 fs/ext4/file.c:311
#3: ffff888076ccd978 (mapping.invalidate_lock#2){++++}-{4:4}, at: filemap_invalidate_lock include/linux/fs.h:1079 [inline]
#3: ffff888076ccd978 (mapping.invalidate_lock#2){++++}-{4:4}, at: ext4_truncate_failed_write fs/ext4/truncate.h:20 [inline]
#3: ffff888076ccd978 (mapping.invalidate_lock#2){++++}-{4:4}, at: ext4_write_end+0x713/0x9e0 fs/ext4/inode.c:1495
1 lock held by syz.5.1177/11014:
#0: ffff888076ccd978 (mapping.invalidate_lock#2){++++}-{4:4}, at: filemap_invalidate_lock_shared include/linux/fs.h:1089 [inline]
#0: ffff888076ccd978 (mapping.invalidate_lock#2){++++}-{4:4}, at: page_cache_ra_order+0x3eb/0xee0 mm/readahead.c:517
4 locks held by syz.8.1536/12449:
#0: ffff8880339f1cf0 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x246/0x320 fs/file.c:1259
#1: ffff88807b69a450 (sb_writers#4){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2728 [inline]
#1: ffff88807b69a450 (sb_writers#4){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683
#2: ffff888076c8ce80 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline]
#2: ffff888076c8ce80 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: ext4_buffered_write_iter+0x9c/0x370 fs/ext4/file.c:311
#3: ffff888076c8d018 (mapping.invalidate_lock#2){++++}-{4:4}, at: filemap_invalidate_lock include/linux/fs.h:1079 [inline]
#3: ffff888076c8d018 (mapping.invalidate_lock#2){++++}-{4:4}, at: ext4_truncate_failed_write fs/ext4/truncate.h:20 [inline]
#3: ffff888076c8d018 (mapping.invalidate_lock#2){++++}-{4:4}, at: ext4_write_end+0x713/0x9e0 fs/ext4/inode.c:1495
1 lock held by syz.8.1536/12465:
#0: ffff888076c8d018 (mapping.invalidate_lock#2){++++}-{4:4}, at: filemap_invalidate_lock_shared include/linux/fs.h:1089 [inline]
#0: ffff888076c8d018 (mapping.invalidate_lock#2){++++}-{4:4}, at: page_cache_ra_order+0x3eb/0xee0 mm/readahead.c:517
4 locks held by syz.6.1557/12517:
#0: ffff88807b6eeb70 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x246/0x320 fs/file.c:1259
#1: ffff888057e82450 (sb_writers#4){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2728 [inline]
#1: ffff888057e82450 (sb_writers#4){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683
#2: ffff88806eabd7e0 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline]
#2: ffff88806eabd7e0 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: ext4_buffered_write_iter+0x9c/0x370 fs/ext4/file.c:311
#3: ffff88806eabd978 (mapping.invalidate_lock#2){++++}-{4:4}, at: filemap_invalidate_lock include/linux/fs.h:1079 [inline]
#3: ffff88806eabd978 (mapping.invalidate_lock#2){++++}-{4:4}, at: ext4_truncate_failed_write fs/ext4/truncate.h:20 [inline]
#3: ffff88806eabd978 (mapping.invalidate_lock#2){++++}-{4:4}, at: ext4_write_end+0x713/0x9e0 fs/ext4/inode.c:1495
1 lock held by syz.6.1557/12533:
#0: ffff88806eabd978 (mapping.invalidate_lock#2){++++}-{4:4}, at: filemap_invalidate_lock_shared include/linux/fs.h:1089 [inline]
#0: ffff88806eabd978 (mapping.invalidate_lock#2){++++}-{4:4}, at: page_cache_ra_order+0x3eb/0xee0 mm/readahead.c:517
1 lock held by syz-executor/13000:
#0: ffffffff8fdecec0 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
#0: ffffffff8fdecec0 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
#0: ffffffff8fdecec0 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8a3/0x1bd0 net/core/rtnetlink.c:4158
2 locks held by syz-executor/13036:
#0: ffffffff8fdde328 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x4e2/0x720 net/core/net_namespace.c:575
#1: ffffffff8fdecec0 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock_killable include/linux/rtnetlink.h:145 [inline]
#1: ffffffff8fdecec0 (rtnl_mutex){+.+.}-{4:4}, at: register_netdev+0x18/0x60 net/core/dev.c:11553
2 locks held by dhcpcd/13097:
#0: ffff888058895880 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline]
#0: ffff888058895880 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: __sock_release net/socket.c:709 [inline]
#0: ffff888058895880 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: sock_close+0x82/0x220 net/socket.c:1501
#1: ffffffff8e95ff28 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:343 [inline]
#1: ffffffff8e95ff28 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x38d/0x770 kernel/rcu/tree_exp.h:961
1 lock held by dhcpcd/13113:
#0: ffff888070c80260 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1713 [inline]
#0: ffff888070c80260 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x33/0xe90 net/packet/af_packet.c:3204
1 lock held by dhcpcd/13127:
#0: ffff888079e76260 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1713 [inline]
#0: ffff888079e76260 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x33/0xe90 net/packet/af_packet.c:3204
3 locks held by syz.0.1755/13140:
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 32 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Call Trace:
<TASK>
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:122
nmi_trigger_cpumask_backtrace+0x17a/0x380 lib/nmi_backtrace.c:65
trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
__sys_info lib/sys_info.c:157 [inline]
sys_info+0x135/0x170 lib/sys_info.c:165
check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline]
watchdog+0xfd7/0x1030 kernel/hung_task.c:561
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 11424 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:io_serial_in+0x77/0xc0 drivers/tty/serial/8250/8250_port.c:401
Code: e8 de 15 7a fc 44 89 f9 d3 e3 49 83 c6 40 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 4f 9a e7 fc 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f e9 f5 f4 c3 fb cc 44 89 f9 80 e1 07
RSP: 0018:ffffc9000396f5a8 EFLAGS: 00000002
RAX: 1ffffffff3501500 RBX: 00000000000003fd RCX: 0000000000000000
RDX: 00000000000003fd RSI: 0000000000000000 RDI: 0000000000000020
RBP: dffffc0000000000 R08: ffff8880264f0237 R09: 1ffff11004c9e046
R10: dffffc0000000000 R11: ffffffff854c4b90 R12: dffffc0000000000
R13: 0000000000000000 R14: ffffffff9a80ae80 R15: 0000000000000000
FS: 000055558b7f8500(0000) GS:ffff888125320000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000010000 CR3: 000000002cc76000 CR4: 0000000000350ef0
Call Trace:
<TASK>
serial_in drivers/tty/serial/8250/8250.h:128 [inline]
serial_lsr_in drivers/tty/serial/8250/8250.h:150 [inline]
wait_for_lsr+0x184/0x2f0 drivers/tty/serial/8250/8250_port.c:1982
serial8250_fifo_wait_for_lsr_thre drivers/tty/serial/8250/8250_port.c:3229 [inline]
serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3294 [inline]
serial8250_console_write+0x12ef/0x1ba0 drivers/tty/serial/8250/8250_port.c:3379
console_emit_next_record kernel/printk/printk.c:3183 [inline]
console_flush_one_record kernel/printk/printk.c:3269 [inline]
console_flush_all+0x6ea/0xaf0 kernel/printk/printk.c:3343
__console_flush_and_unlock kernel/printk/printk.c:3373 [inline]
console_unlock+0xd1/0x1c0 kernel/printk/printk.c:3413
vprintk_emit+0x485/0x560 kernel/printk/printk.c:2479
_printk+0xdd/0x130 kernel/printk/printk.c:2504
__ext4_msg+0x2b9/0x2d0 fs/ext4/super.c:1001
ext4_put_super+0xb6/0xd80 fs/ext4/super.c:1302
generic_shutdown_super+0x13d/0x2d0 fs/super.c:647
kill_block_super+0x44/0x90 fs/super.c:1665
ext4_kill_sb+0x68/0xb0 fs/ext4/super.c:7499
deactivate_locked_super+0xbc/0x130 fs/super.c:477
cleanup_mnt+0x3d3/0x460 fs/namespace.c:1317
task_work_run+0x1d9/0x270 kernel/task_work.c:233
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
__exit_to_user_mode_loop kernel/entry/common.c:70 [inline]
exit_to_user_mode_loop+0x1fa/0x730 kernel/entry/common.c:101
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
do_syscall_64+0x353/0x580 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8ab759f097
Code: a2 c7 05 5c 26 25 00 00 00 00 00 eb 96 e8 e1 12 00 00 90 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007fffcf334e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f8ab76332ca RCX: 00007f8ab759f097
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007fffcf334f20
RBP: 00007fffcf334f20 R08: 00007fffcf335f20 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fffcf335fb0
R13: 00007f8ab76332ca R14: 000000000005b196 R15: 00007fffcf335ff0
</TASK>
---
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