syzbot

INFO: task syz.2.3979:16870 blocked for more than 143 seconds.
      Not tainted 6.1.112-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.3979      state:D stack:28032 pid:16870 ppid:15969  flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5241 [inline]
 __schedule+0x143f/0x4570 kernel/sched/core.c:6558
 schedule+0xbf/0x180 kernel/sched/core.c:6634
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6693
 rwsem_down_read_slowpath kernel/locking/rwsem.c:1094 [inline]
 __down_read_common kernel/locking/rwsem.c:1261 [inline]
 __down_read kernel/locking/rwsem.c:1274 [inline]
 down_read+0x6ff/0xa30 kernel/locking/rwsem.c:1522
 inode_lock_shared include/linux/fs.h:768 [inline]
 lookup_slow+0x45/0x70 fs/namei.c:1706
 walk_component+0x2d0/0x400 fs/namei.c:1998
 lookup_last fs/namei.c:2455 [inline]
 path_lookupat+0x16f/0x450 fs/namei.c:2479
 filename_lookup+0x251/0x600 fs/namei.c:2508
 user_path_at_empty+0x3e/0x60 fs/namei.c:2907
 user_path_at include/linux/namei.h:57 [inline]
 path_removexattr+0xb3/0x320 fs/xattr.c:887
 __do_sys_removexattr fs/xattr.c:906 [inline]
 __se_sys_removexattr fs/xattr.c:903 [inline]
 __x64_sys_removexattr+0x5c/0x70 fs/xattr.c:903
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f81ffb7dff9
RSP: 002b:00007f81ff9de038 EFLAGS: 00000246 ORIG_RAX: 00000000000000c5
RAX: ffffffffffffffda RBX: 00007f81ffd36058 RCX: 00007f81ffb7dff9
RDX: 0000000000000000 RSI: 00000000200004c0 RDI: 0000000020000140
RBP: 00007f81ffbf0296 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007f81ffd36058 R15: 00007ffd082900d8
 </TASK>

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
 #0: ffffffff8d32b1d0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x29/0xe30 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
 #0: ffffffff8d32b9d0 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x29/0xe30 kernel/rcu/tasks.h:517
1 lock held by khungtaskd/28:
 #0: ffffffff8d32b000 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #0: ffffffff8d32b000 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
 #0: ffffffff8d32b000 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6494
1 lock held by klogd/3082:
2 locks held by getty/3396:
 #0: ffff88802e731098 (&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:2198
2 locks held by kworker/u4:9/3778:
3 locks held by kworker/0:17/13315:
3 locks held by kworker/1:19/13711:
2 locks held by syz.2.3979/16867:
1 lock held by syz.2.3979/16870:
 #0: ffff88807a8f0188 (&type->i_mutex_dir_key#9){.+.+}-{3:3}, at: inode_lock_shared include/linux/fs.h:768 [inline]
 #0: ffff88807a8f0188 (&type->i_mutex_dir_key#9){.+.+}-{3:3}, at: lookup_slow+0x45/0x70 fs/namei.c:1706
2 locks held by kworker/u4:13/18397:
1 lock held by syz.4.4420/18414:
2 locks held by syz.1.4426/18442:
1 lock held by syz.3.4428/18444:

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

NMI backtrace for cpu 1
CPU: 1 PID: 28 Comm: khungtaskd Not tainted 6.1.112-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
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+0x1ae/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:295
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 13315 Comm: kworker/0:17 Not tainted 6.1.112-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Workqueue: events_power_efficient wg_ratelimiter_gc_entries
RIP: 0010:instrument_atomic_read include/linux/instrumented.h:72 [inline]
RIP: 0010:_test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
RIP: 0010:hlock_class kernel/locking/lockdep.c:228 [inline]
RIP: 0010:__lock_acquire+0x11c6/0x1f80 kernel/locking/lockdep.c:5046
Code: 00 41 0f b6 04 3f 84 c0 0f 85 09 0a 00 00 48 8b 44 24 08 8b 18 81 e3 ff 1f 00 00 48 89 d8 48 c1 e8 06 48 8d 3c c5 20 d2 1d 91 <be> 08 00 00 00 e8 70 97 77 00 48 0f a3 1d 78 36 b3 0f 73 1b 48 8d
RSP: 0018:ffffc9000b0af9a0 EFLAGS: 00000007
RAX: 000000000000001b RBX: 00000000000006e6 RCX: ffffffff816a9947
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff911dd2f8
RBP: 2d4660996da0e776 R08: dffffc0000000000 R09: fffffbfff223ba60
R10: 0000000000000000 R11: dffffc0000000001 R12: ffff888026bea898
R13: ffff888026be9dc0 R14: 0000000000000000 R15: 1ffff11004d7d522
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2f91dff8 CR3: 00000000660e0000 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 include/linux/spinlock_api_smp.h:133 [inline]
 _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154
 spin_lock include/linux/spinlock.h:351 [inline]
 wg_ratelimiter_gc_entries+0x5c/0x470 drivers/net/wireguard/ratelimiter.c:63
 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:295
 </TASK>