syzbot

INFO: task syz-executor.0:4301 blocked for more than 143 seconds.
      Not tainted 6.1.86-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.0  state:D stack:21192 pid:4301  ppid:1      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
 wb_wait_for_completion+0x162/0x290 fs/fs-writeback.c:191
 __writeback_inodes_sb_nr+0x2ce/0x370 fs/fs-writeback.c:2653
 sync_filesystem+0xa0/0x220 fs/sync.c:54
 generic_shutdown_super+0x6b/0x340 fs/super.c:474
 kill_block_super+0x7a/0xe0 fs/super.c:1459
 deactivate_locked_super+0xa0/0x110 fs/super.c:332
 cleanup_mnt+0x490/0x520 fs/namespace.c:1186
 task_work_run+0x246/0x300 kernel/task_work.c:179
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0xde/0x100 kernel/entry/common.c:177
 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
 syscall_exit_to_user_mode+0x60/0x270 kernel/entry/common.c:303
 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:87
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fbd8ec7f1d7
RSP: 002b:00007ffd81588b48 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007fbd8ec7f1d7
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffd81588c00
RBP: 00007ffd81588c00 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffd81589cc0
R13: 00007fbd8ecc93b9 R14: 0000000000032011 R15: 000000000000001e
 </TASK>

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
 #0: ffffffff8d12ae10 (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: ffffffff8d12b610 (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: ffffffff8d12ac40 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #0: ffffffff8d12ac40 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
 #0: ffffffff8d12ac40 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6494
2 locks held by getty/3299:
 #0: ffff88814b6d7098 (&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
3 locks held by kworker/u4:7/3816:
1 lock held by syz-executor.0/4301:
 #0: ffff888027ee80e0 (&type->s_umount_key#64){+.+.}-{3:3}, at: deactivate_super+0xa9/0xe0 fs/super.c:362

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

NMI backtrace for cpu 1
CPU: 1 PID: 28 Comm: khungtaskd Not tainted 6.1.86-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
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+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:308
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 2992 Comm: klogd Not tainted 6.1.86-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
RIP: 0010:cmpxchg_double_slab+0x125/0x310 mm/slub.c:552
Code: 02 00 00 0f 84 8c 00 00 00 fb e9 86 00 00 00 41 8d 46 20 a8 0f 0f 85 60 01 00 00 4c 89 f9 4c 89 e2 4c 89 e8 f0 49 0f c7 4e 20 <b0> 01 74 67 eb 61 49 8b 46 08 a8 01 0f 85 73 01 00 00 0f 1f 44 00
RSP: 0018:ffffc9000317f668 EFLAGS: 00000246
RAX: ffff88804603fdc0 RBX: ffff88804603f8c0 RCX: 00000000000c0002
RDX: 00000000000c0003 RSI: ffffea0001180fc0 RDI: ffff888140a52500
RBP: 00000000000c0002 R08: ffff88804603f8c0 R09: 00000000000c0002
R10: 0000000000000000 R11: dffffc0000000001 R12: 00000000000c0003
R13: ffff88804603fdc0 R14: ffffea0001180fc0 R15: 00000000000c0002
FS:  00007f957869d380(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055f1081d6030 CR3: 0000000028fe1000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 __slab_free+0x9c/0x280 mm/slub.c:3520
 qlink_free mm/kasan/quarantine.c:168 [inline]
 qlist_free_all+0x76/0xe0 mm/kasan/quarantine.c:187
 kasan_quarantine_reduce+0x156/0x170 mm/kasan/quarantine.c:294
 __kasan_slab_alloc+0x1f/0x70 mm/kasan/common.c:305
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook+0x52/0x3a0 mm/slab.h:737
 slab_alloc_node mm/slub.c:3398 [inline]
 kmem_cache_alloc_node+0x136/0x310 mm/slub.c:3443
 __alloc_skb+0xde/0x670 net/core/skbuff.c:505
 alloc_skb include/linux/skbuff.h:1271 [inline]
 alloc_skb_with_frags+0xa4/0x740 net/core/skbuff.c:6157
 sock_alloc_send_pskb+0x915/0xa50 net/core/sock.c:2746
 unix_dgram_sendmsg+0x5b1/0x2050 net/unix/af_unix.c:1939
 sock_sendmsg_nosec net/socket.c:718 [inline]
 __sock_sendmsg net/socket.c:730 [inline]
 __sys_sendto+0x480/0x600 net/socket.c:2148
 __do_sys_sendto net/socket.c:2160 [inline]
 __se_sys_sendto net/socket.c:2156 [inline]
 __x64_sys_sendto+0xda/0xf0 net/socket.c:2156
 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: 0033:0x7f95787ff9b5
Code: 8b 44 24 08 48 83 c4 28 48 98 c3 48 98 c3 41 89 ca 64 8b 04 25 18 00 00 00 85 c0 75 26 45 31 c9 45 31 c0 b8 2c 00 00 00 0f 05 <48> 3d 00 f0 ff ff 76 7a 48 8b 15 44 c4 0c 00 f7 d8 64 89 02 48 83
RSP: 002b:00007ffe205a84b8 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007f95787ff9b5
RDX: 0000000000000071 RSI: 000055b89c531780 RDI: 0000000000000003
RBP: 000055b89c52a910 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000004000 R11: 0000000000000246 R12: 0000000000000013
R13: 00007f957898d212 R14: 00007ffe205a85b8 R15: 0000000000000000
 </TASK>