[v6.1] INFO: task hung in path_openat (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 4aa6747d9352 Linux 6.1.69
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=164ca855e80000
kernel config: https://syzkaller.appspot.com/x/.config?x=e1e9066810307299
dashboard link: https://syzkaller.appspot.com/bug?extid=6a49c9c38e2ef935c9ce
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/209330361447/disk-4aa6747d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/48aa2c86988d/vmlinux-4aa6747d.xz
kernel image: https://storage.googleapis.com/syzbot-assets/84320338eba6/bzImage-4aa6747d.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+6a49c9...@syzkaller.appspotmail.com

INFO: task syz-executor.0:18064 blocked for more than 143 seconds.
Not tainted 6.1.69-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.0 state:D stack:28312 pid:18064 ppid:3588 flags:0x00004006
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5245 [inline]
__schedule+0x142d/0x4550 kernel/sched/core.c:6558
schedule+0xbf/0x180 kernel/sched/core.c:6634
rwsem_down_write_slowpath+0xea1/0x14b0 kernel/locking/rwsem.c:1189
inode_lock include/linux/fs.h:756 [inline]
open_last_lookups fs/namei.c:3479 [inline]
path_openat+0x7b6/0x2e60 fs/namei.c:3712
do_filp_open+0x230/0x480 fs/namei.c:3742
do_sys_openat2+0x13b/0x500 fs/open.c:1318
do_sys_open fs/open.c:1334 [inline]
__do_sys_open fs/open.c:1342 [inline]
__se_sys_open fs/open.c:1338 [inline]
__x64_sys_open+0x221/0x270 fs/open.c:1338
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f4ce267cce9
RSP: 002b:00007f4ce11bc0c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 00007f4ce279c120 RCX: 00007f4ce267cce9
RDX: 0000000000000000 RSI: 000000000014d27e RDI: 0000000020000180
RBP: 00007f4ce26c947a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000006e R14: 00007f4ce279c120 R15: 00007ffedf998a98
</TASK>

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
#0: ffffffff8d12a4f0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x29/0xe30 kernel/rcu/tasks.h:516
1 lock held by rcu_tasks_trace/13:
#0: ffffffff8d12acf0 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x29/0xe30 kernel/rcu/tasks.h:516
1 lock held by khungtaskd/28:
#0: ffffffff8d12a320 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:306 [inline]
#0: ffffffff8d12a320 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:747 [inline]
#0: ffffffff8d12a320 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6494
2 locks held by getty/3303:
#0: ffff888028d5c098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
#1: ffffc900031262f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6a7/0x1db0 drivers/tty/n_tty.c:2188
9 locks held by kworker/u4:24/5235:
2 locks held by syz-executor.0/18059:
2 locks held by syz-executor.0/18064:
#0: ffff8880277c4460 (sb_writers#14){.+.+}-{0:0}, at: mnt_want_write+0x3b/0x80 fs/namespace.c:393
#1: ffff8880aa2a5c20 (&type->i_mutex_dir_key#8){++++}-{3:3}, at: inode_lock include/linux/fs.h:756 [inline]
#1: ffff8880aa2a5c20 (&type->i_mutex_dir_key#8){++++}-{3:3}, at: open_last_lookups fs/namei.c:3479 [inline]
#1: ffff8880aa2a5c20 (&type->i_mutex_dir_key#8){++++}-{3:3}, at: path_openat+0x7b6/0x2e60 fs/namei.c:3712
2 locks held by syz-executor.0/20144:

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

NMI backtrace for cpu 1
CPU: 1 PID: 28 Comm: khungtaskd Not tainted 6.1.69-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
nmi_cpu_backtrace+0x4e1/0x560 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x1b0/0x3f0 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline]
watchdog+0xf88/0xfd0 kernel/hung_task.c:377
kthread+0x28d/0x320 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
</TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 5247 Comm: kworker/u4:30 Not tainted 6.1.69-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
Workqueue: bat_events batadv_nc_worker
RIP: 0010:hlock_class kernel/locking/lockdep.c:228 [inline]
RIP: 0010:check_wait_context kernel/locking/lockdep.c:4723 [inline]
RIP: 0010:__lock_acquire+0x49d/0x1f80 kernel/locking/lockdep.c:4999
Code: 12 00 00 44 89 33 44 89 fb 48 89 d8 48 c1 e8 06 48 8d 3c c5 20 f2 48 90 be 08 00 00 00 e8 1b 9b 77 00 48 0f a3 1d a3 9c de 0e <73> 25 48 8d 04 5b 48 c1 e0 06 48 8d 98 20 51 18 90 48 ba 00 00 00
RSP: 0018:ffffc9000589f900 EFLAGS: 00000057
RAX: 0000000000000001 RBX: 00000000000006c6 RCX: ffffffff816a5575
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff9048f2f8
RBP: ffff8880742ba884 R08: dffffc0000000000 R09: fffffbfff2091e60
R10: 0000000000000000 R11: dffffc0000000001 R12: ffff8880742ba898
R13: ffff8880742b9dc0 R14: 0000000000000000 R15: 00000000000006c6
FS: 0000000000000000(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c039003000 CR3: 000000000ce8e000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<NMI>
</NMI>
<TASK>
lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662
__raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
_raw_spin_lock_bh+0x31/0x40 kernel/locking/spinlock.c:178
spin_lock_bh include/linux/spinlock.h:355 [inline]
batadv_nc_purge_paths+0xe8/0x3b0 net/batman-adv/network-coding.c:442
batadv_nc_worker+0x324/0x610 net/batman-adv/network-coding.c:720
process_one_work+0x8a9/0x11d0 kernel/workqueue.c:2292
worker_thread+0xa47/0x1200 kernel/workqueue.c:2439
kthread+0x28d/0x320 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
</TASK>


---
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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: fa3df276cd36 Linux 5.15.155
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=10af0243180000
kernel config: https://syzkaller.appspot.com/x/.config?x=fa45dfd65a261480
dashboard link: https://syzkaller.appspot.com/bug?extid=1816b02f12155a30dc50

compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

userspace arch: arm64

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:

disk image: https://storage.googleapis.com/syzbot-assets/0dc19fc63531/disk-fa3df276.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/fae4c89e243a/vmlinux-fa3df276.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a5c832fcb939/Image-fa3df276.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:

Reported-by: syzbot+1816b0...@syzkaller.appspotmail.com

INFO: task syz-executor.1:4419 blocked for more than 143 seconds.
Not tainted 5.15.155-syzkaller #0

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

task:syz-executor.1 state:D stack: 0 pid: 4419 ppid: 3977 flags:0x00000005
Call trace:
__switch_to+0x308/0x5e8 arch/arm64/kernel/process.c:518
context_switch kernel/sched/core.c:5030 [inline]
__schedule+0xf10/0x1e48 kernel/sched/core.c:6376
schedule+0x11c/0x1c8 kernel/sched/core.c:6459
rwsem_down_write_slowpath+0xd94/0x17e0 kernel/locking/rwsem.c:1165
__down_write_common kernel/locking/rwsem.c:1292 [inline]
__down_write kernel/locking/rwsem.c:1301 [inline]
down_write+0xe8/0x12c kernel/locking/rwsem.c:1552
inode_lock include/linux/fs.h:789 [inline]
open_last_lookups fs/namei.c:3529 [inline]
path_openat+0x640/0x26cc fs/namei.c:3739
do_filp_open+0x1a8/0x3b4 fs/namei.c:3769
do_sys_openat2+0x128/0x3d8 fs/open.c:1253
do_sys_open fs/open.c:1269 [inline]
__do_sys_openat fs/open.c:1285 [inline]
__se_sys_openat fs/open.c:1280 [inline]
__arm64_sys_openat+0x1f0/0x240 fs/open.c:1280
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608
el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

Showing all locks held in the system:

3 locks held by kworker/0:1/13:
#0: ffff0000c0020938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x66c/0x11b8 kernel/workqueue.c:2283
#1: ffff800018997c00 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_one_work+0x6ac/0x11b8 kernel/workqueue.c:2285
#2: ffff0000da563240 (&data->fib_lock){+.+.}-{3:3}, at: nsim_fib_event_work+0x274/0x33c4 drivers/net/netdevsim/fib.c:1478
1 lock held by khungtaskd/27:
#0: ffff800014b114e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0xc/0x44 include/linux/rcupdate.h:311
2 locks held by kworker/u4:2/148:
2 locks held by getty/3724:
#0: ffff0000d2943098 (&tty->ldisc_sem){++++}-{0:0}, at: ldsem_down_read+0x40/0x50 drivers/tty/tty_ldsem.c:340
#1: ffff80001a32e2e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x414/0x1204 drivers/tty/n_tty.c:2158
3 locks held by kworker/0:5/4028:
#0: ffff0000d1c6d138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x66c/0x11b8 kernel/workqueue.c:2283
#1: ffff0001b47ebc48 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x438/0x66c kernel/sched/psi.c:891
#2: ffff0000e2ada458 (&p->pi_lock){-.-.}-{2:2}, at: try_to_wake_up+0xb0/0xc2c kernel/sched/core.c:4030
3 locks held by kworker/u4:8/4201:
#0: ffff0000c038c138 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x66c/0x11b8 kernel/workqueue.c:2283
#1: ffff80001d487c00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x6ac/0x11b8 kernel/workqueue.c:2285
#2: ffff800016a2aa50 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0xf4/0x9bc net/core/net_namespace.c:558
2 locks held by syz-executor.1/4410:
1 lock held by syz-executor.1/4419:
#0: ffff0000df58c188 (&type->i_mutex_dir_key#14){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:789 [inline]
#0: ffff0000df58c188 (&type->i_mutex_dir_key#14){+.+.}-{3:3}, at: open_last_lookups fs/namei.c:3529 [inline]
#0: ffff0000df58c188 (&type->i_mutex_dir_key#14){+.+.}-{3:3}, at: path_openat+0x640/0x26cc fs/namei.c:3739
3 locks held by kworker/0:15/5616:
#0: ffff0000d1c6d138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x66c/0x11b8 kernel/workqueue.c:2283
#1: ffff80001e857c00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x6ac/0x11b8 kernel/workqueue.c:2285
#2: ffff0000c689dad8 (&p->pi_lock){-.-.}-{2:2}, at: try_to_wake_up+0xb0/0xc2c kernel/sched/core.c:4030
3 locks held by kworker/0:16/5617:
#0: ffff0000c0020938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x66c/0x11b8 kernel/workqueue.c:2283
#1: ffff80001e867c00 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_one_work+0x6ac/0x11b8 kernel/workqueue.c:2285
#2: ffff0000d65e8240 (&data->fib_lock){+.+.}-{3:3}, at: nsim_fib_event_work+0x274/0x33c4 drivers/net/netdevsim/fib.c:1478
3 locks held by kworker/1:18/6455:
#0: ffff0000c0020938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x66c/0x11b8 kernel/workqueue.c:2283
#1: ffff80001ca47c00 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_one_work+0x6ac/0x11b8 kernel/workqueue.c:2285
#2: ffff0000cd67b240 (&data->fib_lock){+.+.}-{3:3}, at: nsim_fib_event_work+0x274/0x33c4 drivers/net/netdevsim/fib.c:1478
2 locks held by kworker/1:19/6456:
#0: ffff0000c0021938 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x66c/0x11b8 kernel/workqueue.c:2283
#1: ffff80001d9c7c00 ((work_completion)(&rew.rew_work)){+.+.}-{0:0}, at: process_one_work+0x6ac/0x11b8 kernel/workqueue.c:2285
1 lock held by syz-executor.4/6690:
#0: ffff800014b15ae8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:290 [inline]
#0: ffff800014b15ae8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x320/0x660 kernel/rcu/tree_exp.h:845
3 locks held by syz-executor.1/6831:
#0: ffff800016a36228 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
#0: ffff800016a36228 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0xa2c/0xdac net/core/rtnetlink.c:5626
#1: ffff0000f0bcd3e8 (&wg->device_update_lock){+.+.}-{3:3}, at: wg_open+0x20c/0x430 drivers/net/wireguard/device.c:49
#2: ffff800014b15ae8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:322 [inline]
#2: ffff800014b15ae8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x2f0/0x660 kernel/rcu/tree_exp.h:845
1 lock held by syz-executor.3/6839:
#0: ffff800016a36228 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
#0: ffff800016a36228 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0xa2c/0xdac net/core/rtnetlink.c:5626
1 lock held by syz-executor.2/6855:
#0: ffff800016a36228 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
#0: ffff800016a36228 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0xa2c/0xdac net/core/rtnetlink.c:5626
2 locks held by syz-executor.0/7054:

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