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

From: syzbot
Date: Thu Aug 17 2023 - 07:38:15 EST


Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
INFO: rcu detected stall in process_one_work

rcu: INFO: rcu_preempt detected expedited stalls on CPUs/tasks: { 0-...D } 2685 jiffies s: 52849 root: 0x1/.
rcu: blocking rcu_node structures (internal RCU debug):
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 12 Comm: kworker/u4:1 Not tainted 6.5.0-rc5-syzkaller-00194-gace0ab3a4b54-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
Workqueue: bat_events batadv_bla_periodic_work
RIP: 0010:__sanitizer_cov_trace_const_cmp4+0x0/0x20 kernel/kcov.c:303
Code: d6 fe ff ff 66 0f 1f 44 00 00 f3 0f 1e fa 48 8b 0c 24 0f b7 d6 0f b7 f7 bf 03 00 00 00 e9 b8 fe ff ff 0f 1f 84 00 00 00 00 00 <f3> 0f 1e fa 48 8b 0c 24 89 f2 89 fe bf 05 00 00 00 e9 9a fe ff ff
RSP: 0018:ffffc90000007e38 EFLAGS: 00000046
RAX: 0000000000000001 RBX: ffff8880b982b980 RCX: 0000000000000001
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 0000000000000001 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 000000000000004e R12: ffff8880b982b880
R13: 177c2886f5028478 R14: ffff8880719ee340 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa162667440 CR3: 000000000c776000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<NMI>
</NMI>
<IRQ>
__run_hrtimer kernel/time/hrtimer.c:1654 [inline]
__hrtimer_run_queues+0x964/0xc10 kernel/time/hrtimer.c:1752
hrtimer_interrupt+0x31b/0x800 kernel/time/hrtimer.c:1814
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1098 [inline]
__sysvec_apic_timer_interrupt+0x14a/0x430 arch/x86/kernel/apic/apic.c:1115
sysvec_apic_timer_interrupt+0x8e/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:queue_delayed_work_on+0x9a/0x130 kernel/workqueue.c:1908
Code: ff 48 89 ee e8 c7 26 31 00 48 85 ed 75 42 e8 2d 2b 31 00 9c 5b 81 e3 00 02 00 00 31 ff 48 89 de e8 ab 26 31 00 48 85 db 75 71 <e8> 11 2b 31 00 44 89 e8 48 83 c4 08 5b 5d 41 5c 41 5d 41 5e 41 5f
RSP: 0018:ffffc90000117cb0 EFLAGS: 00000293
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: ffff88801664d940 RSI: ffffffff8154ddd6 RDI: 0000000000000007
RBP: 0000000000000200 R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000000 R11: 000000000000004e R12: ffff88801465ad00
R13: 0000000000000001 R14: ffff888028eae000 R15: 00000000000003e8
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>


Tested on:

commit: ace0ab3a Revert "vlan: Fix VLAN 0 memory leak"
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git
console output: https://syzkaller.appspot.com/x/log.txt?x=160073c3a80000
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
patch: https://syzkaller.appspot.com/x/patch.diff?x=13c69eefa80000