Subject: [syzbot] [ceph?] [net?] INFO: task hung in ceph_monc_stop

From: syzbot <[email-masked]>
Date: Tue, 06 Feb 2024 18:53:29 -0800

Hello,

syzbot found the following issue on:

HEAD commit:    076d56d74f17 Add linux-next specific files for 20240202
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=109a7ccbe80000
kernel config:  https://syzkaller.appspot.com/x/.config?x=428086ff1c010d9f
dashboard link: https://syzkaller.appspot.com/bug?extid=388fe6c0b08b54d6d8f9
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=157cf5b0180000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=103ae618180000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/dece45d1a4b5/disk-076d56d7.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/4921e269b178/vmlinux-076d56d7.xz
kernel image: https://storage.googleapis.com/syzbot-assets/2a9156da9091/bzImage-076d56d7.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email-masked]

INFO: task syz-executor388:5228 blocked for more than 143 seconds.
      Not tainted 6.8.0-rc2-next-20240202-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor388 state:D stack:25328 pid:5228  tgid:5228  ppid:5095   flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5400 [inline]
 __schedule+0x17df/0x4a40 kernel/sched/core.c:6727
 __schedule_loop kernel/sched/core.c:6804 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6819
 schedule_timeout+0xb0/0x310 kernel/time/timer.c:2159
 do_wait_for_common kernel/sched/completion.c:95 [inline]
 __wait_for_common kernel/sched/completion.c:116 [inline]
 wait_for_common kernel/sched/completion.c:127 [inline]
 wait_for_completion+0x355/0x620 kernel/sched/completion.c:148
 __flush_workqueue+0x730/0x1630 kernel/workqueue.c:3617
 ceph_monc_stop+0x7c/0x1e0 net/ceph/mon_client.c:1248
 ceph_destroy_client+0x74/0x130 net/ceph/ceph_common.c:768
 destroy_fs_client+0x192/0x270 fs/ceph/super.c:899
 deactivate_locked_super+0xc4/0x130 fs/super.c:477
 ceph_get_tree+0x9a9/0x17b0 fs/ceph/super.c:1361
 vfs_get_tree+0x90/0x2a0 fs/super.c:1784
 vfs_cmd_create+0xe4/0x230 fs/fsopen.c:230
 __do_sys_fsconfig fs/fsopen.c:476 [inline]
 __se_sys_fsconfig+0x967/0xec0 fs/fsopen.c:349
 do_syscall_64+0xfb/0x240
 entry_SYSCALL_64_after_hwframe+0x6d/0x75
RIP: 0033:0x7fa0aaddda39
RSP: 002b:00007ffeca02e718 EFLAGS: 00000246 ORIG_RAX: 00000000000001af
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fa0aaddda39
RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0000000000000003
RBP: 00000000000a06e0 R08: 0000000000000000 R09: 0000000000000006
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffeca02e72c
R13: 431bde82d7b634db R14: 0000000000000001 R15: 0000000000000001
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/29:
 #0: ffffffff8e130d60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:298 [inline]
 #0: ffffffff8e130d60 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:750 [inline]
 #0: ffffffff8e130d60 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6614
1 lock held by kworker/u4:4/79:
 #0: ffff8880b943c758 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:559
2 locks held by getty/4824:
 #0: ffff88802aa2e0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc90002f062f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6b5/0x1e10 drivers/tty/n_tty.c:2201
1 lock held by syz-executor388/5228:
 #0: ffff888023aa6070 (&fc->uapi_mutex){+.+.}-{3:3}, at: __do_sys_fsconfig fs/fsopen.c:474 [inline]
 #0: ffff888023aa6070 (&fc->uapi_mutex){+.+.}-{3:3}, at: __se_sys_fsconfig+0x8e6/0xec0 fs/fsopen.c:349

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

NMI backtrace for cpu 1
CPU: 1 PID: 29 Comm: khungtaskd Not tainted 6.8.0-rc2-next-20240202-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e7/0x2e0 lib/dump_stack.c:106
 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:160 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline]
 watchdog+0xfb0/0xff0 kernel/hung_task.c:379
 kthread+0x2f0/0x390 kernel/kthread.c:388
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:242
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 79 Comm: kworker/u4:4 Not tainted 6.8.0-rc2-next-20240202-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:load_new_mm_cr3+0x164/0x210 arch/x86/mm/tlb.c:300
Code: ff 07 00 00 73 56 41 f7 c5 00 08 00 00 75 5e 41 ff c5 41 0f b7 c5 48 09 c1 48 b8 00 00 00 00 00 00 00 80 48 09 c8 0f 22 d8 5b <41> 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc 90 0f 0b 90 eb a6 90 0f
RSP: 0018:ffffc900020df650 EFLAGS: 00000046
RAX: 0000000014c6e000 RBX: 0000000000000001 RCX: ffff888017bd9e00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900020df770 R08: ffffffff8141cf6c R09: 1ffff1100298e0c4
R10: dffffc0000000000 R11: ffffed100298e0c5 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: ffff888014c6e000
FS:  0000000000000000(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000559e76ed7600 CR3: 0000000014c6e000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 switch_mm_irqs_off+0x7c1/0xae0
 use_temporary_mm arch/x86/kernel/alternative.c:1810 [inline]
 __text_poke+0x713/0xd30 arch/x86/kernel/alternative.c:1921
 text_poke arch/x86/kernel/alternative.c:1985 [inline]
 text_poke_bp_batch+0x8cd/0xb30 arch/x86/kernel/alternative.c:2374
 text_poke_flush arch/x86/kernel/alternative.c:2487 [inline]
 text_poke_finish+0x30/0x50 arch/x86/kernel/alternative.c:2494
 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146
 static_key_enable_cpuslocked+0x136/0x260 kernel/jump_label.c:205
 static_key_enable+0x1a/0x20 kernel/jump_label.c:218
 toggle_allocation_gate+0xb5/0x250 mm/kfence/core.c:826
 process_one_work kernel/workqueue.c:3049 [inline]
 process_scheduled_works+0x913/0x14f0 kernel/workqueue.c:3125
 worker_thread+0xa60/0x1000 kernel/workqueue.c:3206
 kthread+0x2f0/0x390 kernel/kthread.c:388
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:242
 </TASK>
INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.423 msecs

---
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