[syzbot] [ext4?] INFO: task hung in find_inode_fast (4)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 7fa366f1b6e3 Add linux-next specific files for 20241218
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=159f6f44580000
kernel config: https://syzkaller.appspot.com/x/.config?x=26a4b4cc7f877b28
dashboard link: https://syzkaller.appspot.com/bug?extid=fd5533bcd0f7343bb8ca
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14b822df980000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/76406ccde331/disk-7fa366f1.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/49c56a285987/vmlinux-7fa366f1.xz
kernel image: https://storage.googleapis.com/syzbot-assets/92d20cf0cd8a/bzImage-7fa366f1.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/2782fc07dd62/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+fd5533...@syzkaller.appspotmail.com

INFO: task syz.1.1247:10997 blocked for more than 143 seconds.
Not tainted 6.13.0-rc3-next-20241218-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.1247 state:D stack:23416 pid:10997 tgid:10996 ppid:5936 flags:0x00004004
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5371 [inline]
__schedule+0x189f/0x4c80 kernel/sched/core.c:6758
__schedule_loop kernel/sched/core.c:6835 [inline]
schedule+0x14b/0x320 kernel/sched/core.c:6850
__wait_on_freeing_inode+0x1c7/0x2f0 fs/inode.c:2502
find_inode_fast+0x2ab/0x480 fs/inode.c:1103
iget_locked+0x96/0x5a0 fs/inode.c:1475
__ext4_iget+0x25e/0x3fe0 fs/ext4/inode.c:4760
ext4_xattr_inode_cache_find fs/ext4/xattr.c:1548 [inline]
ext4_xattr_inode_lookup_create+0x3b1/0x1c90 fs/ext4/xattr.c:1587
ext4_xattr_block_set+0x272/0x3160 fs/ext4/xattr.c:1916
ext4_xattr_set_handle+0xce0/0x1580 fs/ext4/xattr.c:2458
ext4_xattr_set+0x280/0x3e0 fs/ext4/xattr.c:2560
__vfs_setxattr+0x468/0x4a0 fs/xattr.c:200
__vfs_setxattr_noperm+0x12e/0x660 fs/xattr.c:234
vfs_setxattr+0x221/0x430 fs/xattr.c:321
do_setxattr fs/xattr.c:636 [inline]
filename_setxattr+0x2af/0x430 fs/xattr.c:665
path_setxattrat+0x440/0x510 fs/xattr.c:713
__do_sys_setxattr fs/xattr.c:747 [inline]
__se_sys_setxattr fs/xattr.c:743 [inline]
__x64_sys_setxattr+0xbc/0xe0 fs/xattr.c:743
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f25b4b85d29
RSP: 002b:00007f25b5a9b038 EFLAGS: 00000246 ORIG_RAX: 00000000000000bc
RAX: ffffffffffffffda RBX: 00007f25b4d75fa0 RCX: 00007f25b4b85d29
RDX: 0000000020001400 RSI: 00000000200001c0 RDI: 0000000020000200
RBP: 00007f25b4c01a20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000835 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f25b4d75fa0 R15: 00007ffc3db80438
</TASK>
INFO: task syz.1.1247:11010 blocked for more than 143 seconds.
Not tainted 6.13.0-rc3-next-20241218-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.1247 state:D stack:25968 pid:11010 tgid:10996 ppid:5936 flags:0x00000004
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5371 [inline]
__schedule+0x189f/0x4c80 kernel/sched/core.c:6758
__schedule_loop kernel/sched/core.c:6835 [inline]
schedule+0x14b/0x320 kernel/sched/core.c:6850
mb_cache_entry_wait_unused+0x166/0x250 fs/mbcache.c:148
ext4_evict_ea_inode+0x14a/0x2f0 fs/ext4/xattr.c:480
ext4_evict_inode+0x194/0xf50 fs/ext4/inode.c:185
evict+0x4e8/0x9a0 fs/inode.c:796
ext4_xattr_set_entry+0x17f2/0x1f60 fs/ext4/xattr.c:1847
ext4_xattr_block_set+0x19fa/0x3160 fs/ext4/xattr.c:1959
ext4_xattr_set_handle+0xf89/0x1580 fs/ext4/xattr.c:2449
ext4_xattr_set+0x280/0x3e0 fs/ext4/xattr.c:2560
__vfs_setxattr+0x468/0x4a0 fs/xattr.c:200
__vfs_setxattr_noperm+0x12e/0x660 fs/xattr.c:234
vfs_setxattr+0x221/0x430 fs/xattr.c:321
do_setxattr fs/xattr.c:636 [inline]
filename_setxattr+0x2af/0x430 fs/xattr.c:665
path_setxattrat+0x440/0x510 fs/xattr.c:713
__do_sys_setxattr fs/xattr.c:747 [inline]
__se_sys_setxattr fs/xattr.c:743 [inline]
__x64_sys_setxattr+0xbc/0xe0 fs/xattr.c:743
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f25b4b85d29
RSP: 002b:00007f25b5a7a038 EFLAGS: 00000246 ORIG_RAX: 00000000000000bc
RAX: ffffffffffffffda RBX: 00007f25b4d76080 RCX: 00007f25b4b85d29
RDX: 0000000020000280 RSI: 0000000020000180 RDI: 00000000200000c0
RBP: 00007f25b4c01a20 R08: 0000000000000000 R09: 0000000000000000
R10: 000000000000001b R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007f25b4d76080 R15: 00007ffc3db80438
</TASK>

Showing all locks held in the system:
1 lock held by pool_workqueue_/3:
#0: ffffffff8e93d1f8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:329 [inline]
#0: ffffffff8e93d1f8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x451/0x830 kernel/rcu/tree_exp.h:976
3 locks held by kworker/u8:0/11:
#0: ffff88801ac89148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline]
#0: ffff88801ac89148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1840 kernel/workqueue.c:3310
#1: ffffc90000107c60 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline]
#1: ffffc90000107c60 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1840 kernel/workqueue.c:3310
#2: ffffffff8fcb78c8 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:281
1 lock held by khungtaskd/30:
#0: ffffffff8e937d20 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
#0: ffffffff8e937d20 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffffffff8e937d20 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6744
4 locks held by kworker/u8:2/35:
#0: ffff88801baf5948 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline]
#0: ffff88801baf5948 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1840 kernel/workqueue.c:3310
#1: ffffc90000ab7c60 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline]
#1: ffffc90000ab7c60 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1840 kernel/workqueue.c:3310
#2: ffffffff8fcab410 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0x16a/0xd50 net/core/net_namespace.c:602
#3: ffffffff8fcb78c8 (rtnl_mutex){+.+.}-{4:4}, at: ieee80211_unregister_hw+0x55/0x2c0 net/mac80211/main.c:1669
3 locks held by kworker/u8:3/51:
1 lock held by dhcpcd/5500:
#0: ffffffff8fcb78c8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:128 [inline]
#0: ffffffff8fcb78c8 (rtnl_mutex){+.+.}-{4:4}, at: devinet_ioctl+0x31a/0x1ac0 net/ipv4/devinet.c:1129
2 locks held by getty/5588:
#0: ffff88814dc720a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc90002fde2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x6a6/0x1e00 drivers/tty/n_tty.c:2211
3 locks held by syz.1.1247/10997:
#0: ffff888064ac6420 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x3f/0x90 fs/namespace.c:548
#1: ffff88807f3db580 (&sb->s_type->i_mutex_key#8){++++}-{4:4}, at: inode_lock include/linux/fs.h:863 [inline]
#1: ffff88807f3db580 (&sb->s_type->i_mutex_key#8){++++}-{4:4}, at: vfs_setxattr+0x1e1/0x430 fs/xattr.c:320
#2: ffff88807f3db250 (&ei->xattr_sem){++++}-{4:4}, at: ext4_write_lock_xattr fs/ext4/xattr.h:154 [inline]
#2: ffff88807f3db250 (&ei->xattr_sem){++++}-{4:4}, at: ext4_xattr_set_handle+0x277/0x1580 fs/ext4/xattr.c:2373
3 locks held by syz.1.1247/11010:
#0: ffff888064ac6420 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x3f/0x90 fs/namespace.c:548
#1: ffff8880770cb580 (&sb->s_type->i_mutex_key#8){++++}-{4:4}, at: inode_lock include/linux/fs.h:863 [inline]
#1: ffff8880770cb580 (&sb->s_type->i_mutex_key#8){++++}-{4:4}, at: vfs_setxattr+0x1e1/0x430 fs/xattr.c:320
#2: ffff8880770cb250 (&ei->xattr_sem){++++}-{4:4}, at: ext4_write_lock_xattr fs/ext4/xattr.h:154 [inline]
#2: ffff8880770cb250 (&ei->xattr_sem){++++}-{4:4}, at: ext4_xattr_set_handle+0x277/0x1580 fs/ext4/xattr.c:2373
3 locks held by syz-executor/17768:
#0: ffffffff8f465a40 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
#0: ffffffff8f465a40 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffffffff8f465a40 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x22/0x250 net/core/rtnetlink.c:555
#1: ffffffff8fcb78c8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:79 [inline]
#1: ffffffff8fcb78c8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:326 [inline]
#1: ffffffff8fcb78c8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0xbcb/0x2150 net/core/rtnetlink.c:4010
#2: ffffffff8e93d1f8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:329 [inline]
#2: ffffffff8e93d1f8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x451/0x830 kernel/rcu/tree_exp.h:976

=============================================

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.13.0-rc3-next-20241218-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/25/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
nmi_cpu_backtrace+0x49c/0x4d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x198/0x320 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:234 [inline]
watchdog+0xff6/0x1040 kernel/hung_task.c:397
kthread+0x7a9/0x920 kernel/kthread.c:464
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
</TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 17997 Comm: syz.5.2995 Not tainted 6.13.0-rc3-next-20241218-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/25/2024
RIP: 0010:io_serial_in+0x76/0xb0 drivers/tty/serial/8250/8250_port.c:409
Code: 30 97 49 fc 89 e9 41 d3 e6 48 83 c3 40 48 89 d8 48 c1 e8 03 42 80 3c 38 00 74 08 48 89 df e8 11 0c b0 fc 44 03 33 44 89 f2 ec <0f> b6 c0 5b 41 5e 41 5f 5d c3 cc cc cc cc 89 e9 80 e1 07 38 c1 7c
RSP: 0018:ffffc90004a8eb18 EFLAGS: 00000002
RAX: 1ffffffff34e3c00 RBX: ffffffff9a71e060 RCX: 0000000000000000
RDX: 00000000000003fd RSI: 0000000000000000 RDI: 0000000000000020
RBP: 0000000000000000 R08: ffffffff85759916 R09: 1ffff11004923046
R10: dffffc0000000000 R11: ffffffff857598d0 R12: dffffc0000000000
R13: ffffffff9a418f30 R14: 00000000000003fd R15: dffffc0000000000
FS: 00007f4547f756c0(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f453de7f000 CR3: 000000007faac000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<NMI>
</NMI>
<TASK>
serial_in drivers/tty/serial/8250/8250.h:137 [inline]
serial_lsr_in drivers/tty/serial/8250/8250.h:159 [inline]
wait_for_lsr drivers/tty/serial/8250/8250_port.c:2088 [inline]
serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3335 [inline]
serial8250_console_write+0x1373/0x1ed0 drivers/tty/serial/8250/8250_port.c:3413
console_emit_next_record kernel/printk/printk.c:3122 [inline]
console_flush_all+0x869/0xeb0 kernel/printk/printk.c:3210
__console_flush_and_unlock kernel/printk/printk.c:3269 [inline]
console_unlock+0x14f/0x3b0 kernel/printk/printk.c:3309
vprintk_emit+0x730/0xa10 kernel/printk/printk.c:2432
_printk+0xd5/0x120 kernel/printk/printk.c:2457
set_capacity_and_notify+0x1ae/0x240 block/genhd.c:86
loop_set_size+0x44/0xb0 drivers/block/loop.c:232
loop_configure+0x9ec/0xeb0 drivers/block/loop.c:1101
lo_ioctl+0x846/0x1f50
blkdev_ioctl+0x57d/0x6a0 block/ioctl.c:693
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:906 [inline]
__se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f454718592b
Code: 00 48 89 44 24 18 31 c0 48 8d 44 24 60 c7 04 24 10 00 00 00 48 89 44 24 08 48 8d 44 24 20 48 89 44 24 10 b8 10 00 00 00 0f 05 <89> c2 3d 00 f0 ff ff 77 1c 48 8b 44 24 18 64 48 2b 04 25 28 00 00
RSP: 002b:00007f4547f74dc0 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007f454718592b
RDX: 0000000000000003 RSI: 0000000000004c00 RDI: 0000000000000004
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000564
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003
R13: 00007f4547f74ef0 R14: 00007f4547f74eb0 R15: 00007f453de00000
</TASK>


---
This report is generated by a bot. It may contain errors.
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syzbot will keep track of this issue. See:
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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]

syzbot has found a reproducer for the following issue on:

HEAD commit: 971199ad2a0f Merge tag 'arm64-fixes' of git://git.kernel.o..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1503c1e2580000
kernel config: https://syzkaller.appspot.com/x/.config?x=d115f113a86997de
dashboard link: https://syzkaller.appspot.com/bug?extid=fd5533bcd0f7343bb8ca
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12dc052f980000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10d3da7c580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/406943a8345c/disk-971199ad.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/06d218aee5c4/vmlinux-971199ad.xz
kernel image: https://storage.googleapis.com/syzbot-assets/56c432aaadf2/bzImage-971199ad.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/cc46824d9bfa/mount_0.gz
fsck result: OK (log: https://syzkaller.appspot.com/x/fsck.log?x=1719f334580000)

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+fd5533...@syzkaller.appspotmail.com

INFO: task syz.1.551:8496 blocked for more than 143 seconds.
Not tainted syzkaller #0

"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.

task:syz.1.551 state:D stack:24424 pid:8496 tgid:8495 ppid:5991 task_flags:0x400140 flags:0x00080002
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x1798/0x4cc0 kernel/sched/core.c:6929
__schedule_loop kernel/sched/core.c:7011 [inline]
schedule+0x165/0x360 kernel/sched/core.c:7026
__wait_on_freeing_inode+0x1c5/0x2f0 fs/inode.c:2494
find_inode_fast+0x2b0/0x470 fs/inode.c:1070
iget_locked+0xaf/0x580 fs/inode.c:1433
__ext4_iget+0x242/0x41c0 fs/ext4/inode.c:5210
ext4_xattr_inode_cache_find fs/ext4/xattr.c:1545 [inline]
ext4_xattr_inode_lookup_create+0x438/0x1c20 fs/ext4/xattr.c:1584
ext4_xattr_ibody_set+0x202/0x6a0 fs/ext4/xattr.c:2263
ext4_xattr_set_handle+0xc9a/0x1590 fs/ext4/xattr.c:2440
ext4_xattr_set+0x230/0x320 fs/ext4/xattr.c:2554
__vfs_setxattr+0x43c/0x480 fs/xattr.c:200
__vfs_setxattr_noperm+0x12d/0x660 fs/xattr.c:234
vfs_setxattr+0x16b/0x2f0 fs/xattr.c:321
do_setxattr fs/xattr.c:636 [inline]
filename_setxattr+0x274/0x600 fs/xattr.c:665
path_setxattrat+0x364/0x3a0 fs/xattr.c:713

__do_sys_setxattr fs/xattr.c:747 [inline]
__se_sys_setxattr fs/xattr.c:743 [inline]
__x64_sys_setxattr+0xbc/0xe0 fs/xattr.c:743

do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fdacd18eec9
RSP: 002b:00007fdace024038 EFLAGS: 00000246 ORIG_RAX: 00000000000000bc
RAX: ffffffffffffffda RBX: 00007fdacd3e5fa0 RCX: 00007fdacd18eec9
RDX: 0000200000001400 RSI: 00002000000001c0 RDI: 0000200000000380
RBP: 00007fdacd211f91 R08: 0000000000000000 R09: 0000000000000000

R10: 0000000000000835 R11: 0000000000000246 R12: 0000000000000000

R13: 00007fdacd3e6038 R14: 00007fdacd3e5fa0 R15: 00007fff7468a358
</TASK>
INFO: task syz.1.551:8508 blocked for more than 144 seconds.
Not tainted syzkaller #0

"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.

task:syz.1.551 state:D stack:26056 pid:8508 tgid:8495 ppid:5991 task_flags:0x400140 flags:0x00080002
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x1798/0x4cc0 kernel/sched/core.c:6929
__schedule_loop kernel/sched/core.c:7011 [inline]
schedule+0x165/0x360 kernel/sched/core.c:7026
mb_cache_entry_wait_unused+0x165/0x250 fs/mbcache.c:148
ext4_evict_ea_inode+0x14d/0x2f0 fs/ext4/xattr.c:481
ext4_evict_inode+0x16f/0xee0 fs/ext4/inode.c:183
evict+0x504/0x9c0 fs/inode.c:810
ext4_xattr_ibody_set+0x510/0x6a0 fs/ext4/xattr.c:2281
ext4_xattr_set_handle+0xc9a/0x1590 fs/ext4/xattr.c:2440
ext4_xattr_set+0x230/0x320 fs/ext4/xattr.c:2554
__vfs_setxattr+0x43c/0x480 fs/xattr.c:200
__vfs_setxattr_noperm+0x12d/0x660 fs/xattr.c:234
vfs_setxattr+0x16b/0x2f0 fs/xattr.c:321
do_setxattr fs/xattr.c:636 [inline]
filename_setxattr+0x274/0x600 fs/xattr.c:665
path_setxattrat+0x364/0x3a0 fs/xattr.c:713

__do_sys_setxattr fs/xattr.c:747 [inline]
__se_sys_setxattr fs/xattr.c:743 [inline]
__x64_sys_setxattr+0xbc/0xe0 fs/xattr.c:743

do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fdacd18eec9
RSP: 002b:00007fdace003038 EFLAGS: 00000246 ORIG_RAX: 00000000000000bc
RAX: ffffffffffffffda RBX: 00007fdacd3e6090 RCX: 00007fdacd18eec9
RDX: 0000200000001400 RSI: 00002000000001c0 RDI: 0000200000000200
RBP: 00007fdacd211f91 R08: 0000000000000000 R09: 0000000000000000

R10: 0000000000000835 R11: 0000000000000246 R12: 0000000000000000

R13: 00007fdacd3e6128 R14: 00007fdacd3e6090 R15: 00007fff7468a358

</TASK>

Showing all locks held in the system:

5 locks held by kworker/u8:0/12:
1 lock held by ksoftirqd/1/23:
#0: ffff888024985b18 (&fq->mq_flush_lock){..-.}-{3:3}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:638
1 lock held by khungtaskd/31:
#0: ffffffff8e13d320 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8e13d320 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8e13d320 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by getty/5577:
#0: ffff88814d3930a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc900036bb2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222
1 lock held by udevd/5892:
#0: ffff888140ac0188 (&root->kernfs_rwsem){++++}-{4:4}, at: kernfs_dop_revalidate+0x9e/0x5d0 fs/kernfs/dir.c:1180
2 locks held by syz-executor/5988:
#0: ffff888024845358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_release+0x1a9/0x650 block/bdev.c:1128
#1: ffff8880b863a058 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:638
1 lock held by syz-executor/5999:
1 lock held by syz-executor/6000:
1 lock held by syz-executor/6003:
#0: ffffffff8e142db8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:343 [inline]
#0: ffffffff8e142db8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b9/0x730 kernel/rcu/tree_exp.h:957
3 locks held by syz.1.551/8496:
#0: ffff88807b85c420 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:508
#1: ffff888058a1ed10 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: inode_lock include/linux/fs.h:980 [inline]
#1: ffff888058a1ed10 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: vfs_setxattr+0x144/0x2f0 fs/xattr.c:320
#2:
ffff888058a1e9f8 (&ei->xattr_sem){++++}-{4:4}, at: ext4_write_lock_xattr fs/ext4/xattr.h:157 [inline]
ffff888058a1e9f8 (&ei->xattr_sem){++++}-{4:4}, at: ext4_xattr_set_handle+0x165/0x1590 fs/ext4/xattr.c:2367
3 locks held by syz.1.551/8508:
#0: ffff88807b85c420 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:508
#1: ffff888058a02a20 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: inode_lock include/linux/fs.h:980 [inline]
#1: ffff888058a02a20 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: vfs_setxattr+0x144/0x2f0 fs/xattr.c:320
#2: ffff888058a02708 (&ei->xattr_sem){++++}-{4:4}, at: ext4_write_lock_xattr fs/ext4/xattr.h:157 [inline]
#2: ffff888058a02708 (&ei->xattr_sem){++++}-{4:4}, at: ext4_xattr_set_handle+0x165/0x1590 fs/ext4/xattr.c:2367
3 locks held by syz.0.1661/13268:
1 lock held by syz.3.1660/13273:
1 lock held by syz.6.1659/13274:

=============================================

NMI backtrace for cpu 0

CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
<TASK>
dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:332 [inline]
watchdog+0xf60/0xfa0 kernel/hung_task.c:495
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x4bc/0x870 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: 13273 Comm: syz.3.1660 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:io_serial_in+0x77/0xc0 drivers/tty/serial/8250/8250_port.c:400
Code: e8 6e 6e a4 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 cf 0c 0a fd 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f e9 55 1b f5 fb cc 44 89 f9 80 e1 07
RSP: 0018:ffffc9000e50f270 EFLAGS: 00000002
RAX: 1ffffffff33a2900 RBX: 00000000000003fd RCX: 0000000000000000

RDX: 00000000000003fd RSI: 0000000000000000 RDI: 0000000000000020

RBP: ffffffff99d14e70 R08: ffff8880240a0237 R09: 1ffff11004814046
R10: dffffc0000000000 R11: ffffffff851b2530 R12: dffffc0000000000
R13: 0000000000000000 R14: ffffffff99d14be0 R15: 0000000000000000
FS: 00007f6d1fcb56c0(0000) GS:ffff888125e12000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 00007f1b77495000 CR3: 0000000026505000 CR4: 0000000000350ef0
Call Trace:

<TASK>
serial_in drivers/tty/serial/8250/8250.h:137 [inline]
serial_lsr_in drivers/tty/serial/8250/8250.h:159 [inline]

wait_for_lsr+0x1a1/0x2f0 drivers/tty/serial/8250/8250_port.c:1961
fifo_wait_for_lsr drivers/tty/serial/8250/8250_port.c:3234 [inline]
serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3257 [inline]
serial8250_console_write+0x134c/0x1ba0 drivers/tty/serial/8250/8250_port.c:3342
console_emit_next_record kernel/printk/printk.c:3111 [inline]
console_flush_all+0x6f3/0xb10 kernel/printk/printk.c:3199
__console_flush_and_unlock kernel/printk/printk.c:3258 [inline]
console_unlock+0xbb/0x190 kernel/printk/printk.c:3298
vprintk_emit+0x4c5/0x590 kernel/printk/printk.c:2423
_printk+0xcf/0x120 kernel/printk/printk.c:2448
__ext4_msg+0x20a/0x2a0 fs/ext4/super.c:992
ext4_parse_param+0x3b3/0x24c0 fs/ext4/super.c:-1
vfs_parse_fs_param+0x1a9/0x420 fs/fs_context.c:146
vfs_parse_fs_qstr fs/fs_context.c:187 [inline]
vfs_parse_fs_string include/linux/fs_context.h:142 [inline]
vfs_parse_monolithic_sep+0x25d/0x320 fs/fs_context.c:227
do_new_mount+0x2cb/0xa10 fs/namespace.c:3723
do_mount fs/namespace.c:4050 [inline]
__do_sys_mount fs/namespace.c:4238 [inline]
__se_sys_mount+0x313/0x410 fs/namespace.c:4215
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f6d1ed9066a
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 1a 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f6d1fcb4e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f6d1fcb4ef0 RCX: 00007f6d1ed9066a
RDX: 0000200000000040 RSI: 0000200000000140 RDI: 00007f6d1fcb4eb0
RBP: 0000200000000040 R08: 00007f6d1fcb4ef0 R09: 0000000000200044
R10: 0000000000200044 R11: 0000000000000246 R12: 0000200000000140
R13: 00007f6d1fcb4eb0 R14: 000000000000056a R15: 000000000000002c
</TASK>


---