[syzbot] [mm?] [usb?] INFO: rcu detected stall in kswapd (3)

From: syzbot
Date: Sun Oct 06 2024 - 16:29:34 EST

Hello,

syzbot found the following issue on:

HEAD commit: e32cde8d2bd7 Merge tag 'sched_ext-for-6.12-rc1-fixes-1' of..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1460a3d0580000
kernel config: https://syzkaller.appspot.com/x/.config?x=286b31f2cf1c36b5
dashboard link: https://syzkaller.appspot.com/bug?extid=bcc7fa5044343fc35941
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=1570339f980000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1260a3d0580000

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7feb34a89c2a/non_bootable_disk-e32cde8d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/9c681f5609bc/vmlinux-e32cde8d.xz
kernel image: https://storage.googleapis.com/syzbot-assets/00b4d54de1d9/bzImage-e32cde8d.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+bcc7fa5044343fc35941@xxxxxxxxxxxxxxxxxxxxxxxxx

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-0): P76/1:b..l
rcu: (detected by 0, t=10502 jiffies, g=21325, q=180 ncpus=1)
task:kswapd0 state:R running task stack:21424 pid:76 tgid:76 ppid:2 flags:0x00004000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5315 [inline]
__schedule+0x1895/0x4b30 kernel/sched/core.c:6675
preempt_schedule_irq+0xfb/0x1c0 kernel/sched/core.c:6997
irqentry_exit+0x5e/0x90 kernel/entry/common.c:354
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:lru_gen_shrink_node mm/vmscan.c:4957 [inline]
RIP: 0010:shrink_node+0x36c0/0x3de0 mm/vmscan.c:5937
Code: 49 8d 9c 24 c8 f9 ff ff 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 80 3c 08 00 74 08 48 89 df e8 03 6e 26 00 4c 8b 2b <49> 8d 84 24 10 fa ff ff 48 89 44 24 38 4c 89 ef e8 fb 88 fe ff 84
RSP: 0018:ffffc90000e477a0 EFLAGS: 00000246
RAX: 1ffff11002624000 RBX: ffff888013120000 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000000000002
RBP: ffffc90000e47a50 R08: ffffffff81d81eb7 R09: 1ffffffff2858b00
R10: dffffc0000000000 R11: fffffbfff2858b01 R12: ffff888013120638
R13: ffff88804fab4000 R14: 0000000000000002 R15: 0000000000000000
kswapd_shrink_node mm/vmscan.c:6765 [inline]
balance_pgdat mm/vmscan.c:6957 [inline]
kswapd+0x1ca3/0x3700 mm/vmscan.c:7226
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>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10499 jiffies! g21325 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: Possible timer handling issue on cpu=0 timer-softirq=12782
rcu: rcu_preempt kthread starved for 10500 jiffies! g21325 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=0
rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt state:I stack:26352 pid:17 tgid:17 ppid:2 flags:0x00004000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5315 [inline]
__schedule+0x1895/0x4b30 kernel/sched/core.c:6675
__schedule_loop kernel/sched/core.c:6752 [inline]
schedule+0x14b/0x320 kernel/sched/core.c:6767
schedule_timeout+0x1be/0x310 kernel/time/timer.c:2615
rcu_gp_fqs_loop+0x2df/0x1330 kernel/rcu/tree.c:2045
rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2247
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>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 UID: 0 PID: 5313 Comm: syz-executor407 Not tainted 6.12.0-rc1-syzkaller-00031-ge32cde8d2bd7 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:xas_store+0xf9/0x1890 lib/xarray.c:847
Code: 83 e6 03 31 ff e8 07 6e d4 f5 48 89 d8 48 83 e0 03 74 1d e8 19 69 d4 f5 48 8b 44 24 60 48 83 c4 78 5b 41 5c 41 5d 41 5e 41 5f <5d> c3 cc cc cc cc 48 89 df 48 85 db 48 89 5c 24 10 0f 84 af 00 00
RSP: 0018:ffffc9000b4e78f0 EFLAGS: 00000282
RAX: 0000000000000000 RBX: 1ffff9200169cf27 RCX: ffff88803c872440
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 1ffff9200169cf27 R08: ffffffff8bc07289 R09: 0000000000000000
R10: ffffc9000b4e7940 R11: fffff5200169cf2b R12: dffffc0000000000
R13: 1ffff9200169cf20 R14: ffffc9000b4e7920 R15: ffffc9000b4e7938
FS: 00007f32942b66c0(0000) GS:ffff88801fc00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f329436f363 CR3: 000000001e2ca000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<IRQ>
</IRQ>
<TASK>
__xa_erase+0x135/0x220 lib/xarray.c:1511
sock_devmem_dontneed+0x37b/0x740 net/core/sock.c:1089
sk_setsockopt+0x73c/0x33b0 net/core/sock.c:1280
do_sock_setsockopt+0x2fb/0x720 net/socket.c:2325
__sys_setsockopt+0x1a2/0x250 net/socket.c:2352
__do_sys_setsockopt net/socket.c:2361 [inline]
__se_sys_setsockopt net/socket.c:2358 [inline]
__x64_sys_setsockopt+0xb5/0xd0 net/socket.c:2358
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f329430cf69
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 c1 1f 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f32942b6238 EFLAGS: 00000246 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 00007f32943941a8 RCX: 00007f329430cf69
RDX: 0000000000000050 RSI: 0000000000000001 RDI: 0000000000000003
RBP: 00007f32943941a0 R08: 0000000000000010 R09: 00007f32942b66c0
R10: 0000000020000000 R11: 0000000000000246 R12: 00007f32943941ac
R13: 0000000000000016 R14: 00007ffc9990f2c0 R15: 00007ffc9990f3a8
</TASK>


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

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.

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup