Subject: [syzbot] [wireguard?] INFO: rcu detected stall in wg_ratelimiter_gc_entries (2)

From: syzbot <[email-masked]>
Date: Thu, 17 Aug 2023 02:15:07 -0700

Hello,

syzbot found the following issue on:

HEAD commit:    ace0ab3a4b54 Revert "vlan: Fix VLAN 0 memory leak"
git tree:       net
console output: https://syzkaller.appspot.com/x/log.txt?x=16153769a80000
kernel config:  https://syzkaller.appspot.com/x/.config?x=3e670757e16affb
dashboard link: https://syzkaller.appspot.com/bug?extid=c1cc0083f159b67cb192
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1227599ba80000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=17414927a80000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/e03bf2f0ff9c/disk-ace0ab3a.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ad6e79c01723/vmlinux-ace0ab3a.xz
kernel image: https://storage.googleapis.com/syzbot-assets/617319e5afb7/bzImage-ace0ab3a.xz

The issue was bisected to:

commit c2368b19807affd7621f7c4638cd2e17fec13021
Author: Jiri Pirko <[email-masked]>
Date:   Fri Jul 29 07:10:35 2022 +0000

    net: devlink: introduce "unregistering" mark and use it during devlinks iteration

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=17901617a80000
final oops:     https://syzkaller.appspot.com/x/report.txt?x=14501617a80000
console output: https://syzkaller.appspot.com/x/log.txt?x=10501617a80000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email-masked]
Fixes: c2368b19807a ("net: devlink: introduce "unregistering" mark and use it during devlinks iteration")

rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-....: (10499 ticks this GP) idle=2d5c/1/0x4000000000000000 softirq=8994/8995 fqs=4737
rcu: 	         hardirqs   softirqs   csw/system
rcu: 	 number:        0          0            0
rcu: 	cputime:    32198      20291           25   ==> 52490(ms)
rcu: 	(t=10500 jiffies g=7889 q=546 ncpus=2)
CPU: 1 PID: 5075 Comm: kworker/1:6 Not tainted 6.5.0-rc5-syzkaller-00194-gace0ab3a4b54 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
Workqueue: events_power_efficient wg_ratelimiter_gc_entries
RIP: 0010:taprio_next_tc_txq net/sched/sch_taprio.c:771 [inline]
RIP: 0010:taprio_dequeue_tc_priority+0x2fb/0x4b0 net/sched/sch_taprio.c:801
Code: 01 00 00 48 be 00 00 00 00 00 fc ff df 48 8b 4c 24 28 48 89 c8 48 c1 e8 03 0f b6 14 30 48 89 c8 83 e0 07 83 c0 01 38 d0 7c 08 <84> d2 0f 85 da 00 00 00 48 8b 04 24 45 0f b7 75 fe 0f b6 00 38 44
RSP: 0000:ffffc900001e0d60 EFLAGS: 00000202
RAX: 0000000000000007 RBX: ffff88806f6f6394 RCX: ffff88807b860b5e
RDX: 0000000000000000 RSI: dffffc0000000000 RDI: dffffc0000000000
RBP: 000000000000000b R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 000000000000004e R12: 0000000000000008
R13: ffff88807b860b60 R14: 0000000000000000 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5ace99f5c0 CR3: 000000006f75b000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 taprio_dequeue+0x12e/0x5f0 net/sched/sch_taprio.c:868
 dequeue_skb net/sched/sch_generic.c:292 [inline]
 qdisc_restart net/sched/sch_generic.c:397 [inline]
 __qdisc_run+0x1c4/0x19d0 net/sched/sch_generic.c:415
 qdisc_run include/net/pkt_sched.h:125 [inline]
 qdisc_run include/net/pkt_sched.h:122 [inline]
 net_tx_action+0x71e/0xc80 net/core/dev.c:5049
 __do_softirq+0x218/0x965 kernel/softirq.c:553
 invoke_softirq kernel/softirq.c:427 [inline]
 __irq_exit_rcu kernel/softirq.c:632 [inline]
 irq_exit_rcu+0xb7/0x120 kernel/softirq.c:644
 sysvec_apic_timer_interrupt+0x93/0xc0 arch/x86/kernel/apic/apic.c:1109
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:645
RIP: 0010:lock_acquire+0x1ef/0x510 kernel/locking/lockdep.c:5729
Code: c1 05 d5 6e 9b 7e 83 f8 01 0f 85 b0 02 00 00 9c 58 f6 c4 02 0f 85 9b 02 00 00 48 85 ed 74 01 fb 48 b8 00 00 00 00 00 fc ff df <48> 01 c3 48 c7 03 00 00 00 00 48 c7 43 08 00 00 00 00 48 8b 84 24
RSP: 0000:ffffc90003e1fb98 EFLAGS: 00000206
RAX: dffffc0000000000 RBX: 1ffff920007c3f75 RCX: 0000000000000001
RDX: 1ffff11003f03c80 RSI: ffffffff8a6c83a0 RDI: ffffffff8ac811a0
RBP: 0000000000000200 R08: 0000000000000000 R09: fffffbfff2309dea
R10: ffffffff9184ef57 R11: 0000000000000000 R12: 0000000000000001
R13: 0000000000000000 R14: ffffffff8d89afb8 R15: 0000000000000000
 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
 _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
 spin_lock include/linux/spinlock.h:351 [inline]
 wg_ratelimiter_gc_entries+0xc6/0x520 drivers/net/wireguard/ratelimiter.c:63
 process_one_work+0xaa2/0x16f0 kernel/workqueue.c:2600
 worker_thread+0x687/0x1110 kernel/workqueue.c:2751
 kthread+0x33a/0x430 kernel/kthread.c:389
 ret_from_fork+0x2c/0x70 arch/x86/kernel/process.c:145
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304
 </TASK>

---
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