Message-ID: <67626c36.050a0220.29fcd0.0086.GAE@google.com>
Date: Tue, 17 Dec 2024 22:31:18 -0800
From: syzbot <syzbot+5294aa7d73bb0fa85bd0@...kaller.appspotmail.com>
To: akpm@...ux-foundation.org, crashfixer001@...il.com, 
	linux-kernel@...r.kernel.org, linux-mm@...ck.org, 
	syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] [mm?] INFO: task hung in __lru_add_drain_all (2)

syzbot has found a reproducer for the following issue on:

HEAD commit:    59dbb9d81adf Merge tag 'xsa465+xsa466-6.13-tag' of git://g..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=164ff4f8580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=1234f097ee657d8b
dashboard link: https://syzkaller.appspot.com/bug?extid=5294aa7d73bb0fa85bd0
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=1649d7e8580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/235f123641b6/disk-59dbb9d8.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/739d8d2f0615/vmlinux-59dbb9d8.xz
kernel image: https://storage.googleapis.com/syzbot-assets/6cb338ffd7a7/bzImage-59dbb9d8.xz
mounted in repro #1: https://storage.googleapis.com/syzbot-assets/346ce4b8e425/mount_0.gz
mounted in repro #2: https://storage.googleapis.com/syzbot-assets/ff16fd187e15/mount_1.gz
mounted in repro #3: https://storage.googleapis.com/syzbot-assets/d04047a87b7d/mount_2.gz
mounted in repro #4: https://storage.googleapis.com/syzbot-assets/81c4fcd3a27a/mount_11.gz
mounted in repro #5: https://storage.googleapis.com/syzbot-assets/593b919eb65c/mount_16.gz
mounted in repro #6: https://storage.googleapis.com/syzbot-assets/429aaeb5fd39/mount_21.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+5294aa7d73bb0fa85bd0@...kaller.appspotmail.com

INFO: task syz-executor:5996 blocked for more than 143 seconds.
      Not tainted 6.13.0-rc3-syzkaller-00026-g59dbb9d81adf #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:19616 pid:5996  tgid:5996  ppid:1      flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5369 [inline]
 __schedule+0x17fb/0x4be0 kernel/sched/core.c:6756
 __schedule_loop kernel/sched/core.c:6833 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6848
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6905
 __mutex_lock_common kernel/locking/mutex.c:665 [inline]
 __mutex_lock+0x7e7/0xee0 kernel/locking/mutex.c:735
 __lru_add_drain_all+0x66/0x560 mm/swap.c:798
 invalidate_bdev+0x76/0xa0 block/bdev.c:101
 generic_shutdown_super+0x139/0x2d0 fs/super.c:642
 kill_block_super+0x44/0x90 fs/super.c:1710
 xfs_kill_sb+0x15/0x50 fs/xfs/xfs_super.c:2089
 deactivate_locked_super+0xc4/0x130 fs/super.c:473
 cleanup_mnt+0x41f/0x4b0 fs/namespace.c:1373
 task_work_run+0x24f/0x310 kernel/task_work.c:239
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x13f/0x340 kernel/entry/common.c:218
 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f36baf87057
RSP: 002b:00007ffd594f4c38 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007f36baf87057
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffd594f4cf0
RBP: 00007ffd594f4cf0 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffd594f5d70
R13: 00007f36bb00180c R14: 00007ffd594f5db0 R15: 0000000000000024
 </TASK>
INFO: task syz-executor:5997 blocked for more than 146 seconds.
      Not tainted 6.13.0-rc3-syzkaller-00026-g59dbb9d81adf #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:20024 pid:5997  tgid:5997  ppid:1      flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5369 [inline]
 __schedule+0x17fb/0x4be0 kernel/sched/core.c:6756
 __schedule_loop kernel/sched/core.c:6833 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6848
 schedule_timeout+0xb0/0x290 kernel/time/sleep_timeout.c:75
 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_work+0xa37/0xc50 kernel/workqueue.c:4231
 __lru_add_drain_all+0x4f6/0x560 mm/swap.c:843
 invalidate_bdev+0x76/0xa0 block/bdev.c:101
 generic_shutdown_super+0x139/0x2d0 fs/super.c:642
 kill_block_super+0x44/0x90 fs/super.c:1710
 xfs_kill_sb+0x15/0x50 fs/xfs/xfs_super.c:2089
 deactivate_locked_super+0xc4/0x130 fs/super.c:473
 cleanup_mnt+0x41f/0x4b0 fs/namespace.c:1373
 task_work_run+0x24f/0x310 kernel/task_work.c:239
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x13f/0x340 kernel/entry/common.c:218
 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5877f87057
RSP: 002b:00007ffd3d19dce8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007f5877f87057
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffd3d19dda0
RBP: 00007ffd3d19dda0 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffd3d19ee20
R13: 00007f587800180c R14: 00007ffd3d19ee60 R15: 0000000000000023
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/30:
 #0: ffffffff8e937ae0 (rcu_read_lock){....}-{1:3}
, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6744
4 locks held by kworker/u8:2/35:
1 lock held by udevd/5193:
2 locks held by getty/5578:
 #0: ffff88803530a0a0 (&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
2 locks held by syz-executor/5996:
 #0: ffff88805fb060e0 (&type->s_umount_key#54){++++}-{4:4}, at: __super_lock fs/super.c:56 [inline]
 #0: ffff88805fb060e0 (&type->s_umount_key#54){++++}-{4:4}, at: __super_lock_excl fs/super.c:71 [inline]
 #0: ffff88805fb060e0 (&type->s_umount_key#54){++++}-{4:4}, at: deactivate_super+0xb5/0xf0 fs/super.c:505
 #1: ffffffff8e9f9ce8 (lock#3){+.+.}-{4:4}, at: __lru_add_drain_all+0x66/0x560 mm/swap.c:798
2 locks held by syz-executor/5997:
 #0: ffff88805fcb40e0 (&type->s_umount_key#54){++++}-{4:4}, at: __super_lock fs/super.c:56 [inline]
 #0: ffff88805fcb40e0 (&type->s_umount_key#54){++++}-{4:4}, at: __super_lock_excl fs/super.c:71 [inline]
 #0: ffff88805fcb40e0 (&type->s_umount_key#54){++++}-{4:4}, at: deactivate_super+0xb5/0xf0 fs/super.c:505
 #1: ffffffff8e9f9ce8 (lock#3){+.+.}-{4:4}, at: __lru_add_drain_all+0x66/0x560 mm/swap.c:798
2 locks held by syz.2.358/10421:
4 locks held by syz.0.359/10425:
2 locks held by syz.5.360/10432:
2 locks held by syz.1.361/10438:
1 lock held by syz.1.361/10439:
4 locks held by rm/10442:
1 lock held by syz.6.362/10444:
2 locks held by syz.6.362/10445:

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.13.0-rc3-syzkaller-00026-g59dbb9d81adf #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+0x2f0/0x390 kernel/kthread.c:389
 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 0 to CPUs 1:
lapbether: lapb_data_request error - 4
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 35 Comm: kworker/u8:2 Not tainted 6.13.0-rc3-syzkaller-00026-g59dbb9d81adf #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/25/2024
Workqueue: events_unbound macvlan_process_broadcast
RIP: 0010:io_serial_in+0x76/0xb0 drivers/tty/serial/8250/8250_port.c:409
Code: 30 33 57 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 b1 10 bb 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:ffffc90000a17f78 EFLAGS: 00000002
RAX: 1ffffffff34d7a00 RBX: ffffffff9a6bd5e0 RCX: 0000000000000000
RDX: 00000000000003fd RSI: 0000000000000000 RDI: 0000000000000020
RBP: 0000000000000000 R08: ffffffff85484066 R09: 1ffff1100497a046
R10: dffffc0000000000 R11: ffffffff85484020 R12: dffffc0000000000
R13: ffffffff9a3b7f70 R14: 00000000000003fd R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fea64077ff8 CR3: 000000000e736000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <IRQ>
 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
 lapbeth_xmit+0x1dc/0x260 drivers/net/wan/lapbether.c:225
 __netdev_start_xmit include/linux/netdevice.h:5002 [inline]
 netdev_start_xmit include/linux/netdevice.h:5011 [inline]
 xmit_one net/core/dev.c:3590 [inline]
 dev_hard_start_xmit+0x27a/0x7d0 net/core/dev.c:3606
 __dev_queue_xmit+0x1b73/0x3f50 net/core/dev.c:4434
 x25_link_control+0x626/0xb50
 x25_receive_data net/x25/x25_dev.c:43 [inline]
 x25_lapb_receive_frame+0x3d0/0x1010 net/x25/x25_dev.c:127
 __netif_receive_skb_one_core net/core/dev.c:5672 [inline]
 netif_receive_skb_core+0x3f0/0x400 net/core/dev.c:5697
 lapbeth_napi_poll+0x42/0x90 drivers/net/wan/lapbether.c:99
 __napi_poll+0xcb/0x490 net/core/dev.c:6883
 napi_poll net/core/dev.c:6952 [inline]
 net_rx_action+0x89b/0x1240 net/core/dev.c:7074
 handle_softirqs+0x2d4/0x9b0 kernel/softirq.c:561
 do_softirq+0x11b/0x1e0 kernel/softirq.c:462
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0x1bb/0x200 kernel/softirq.c:389
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 netif_rx+0x83/0x90 net/core/dev.c:5257
 macvlan_broadcast+0x3c4/0x670 drivers/net/macvlan.c:290
 macvlan_process_broadcast+0x50e/0x7f0 drivers/net/macvlan.c:338
 process_one_work kernel/workqueue.c:3229 [inline]
 process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3310
 worker_thread+0x870/0xd30 kernel/workqueue.c:3391
 kthread+0x2f0/0x390 kernel/kthread.c:389
 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>
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4
lapbether: lapb_data_request error - 4


---
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.

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