Subject: [syzbot] [wireguard?] KCSAN: data-race in wg_packet_handshake_receive_worker / wg_packet_rx_poll (5)

From: syzbot <[email-masked]>
Date: Mon, 28 Aug 2023 07:37:59 -0700

Hello,

syzbot found the following issue on:

HEAD commit:    93f5de5f648d Merge tag 'acpi-6.5-rc8' of git://git.kernel...
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=10f3d75ba80000
kernel config:  https://syzkaller.appspot.com/x/.config?x=f12c32a009b80107
dashboard link: https://syzkaller.appspot.com/bug?extid=80a98381230162731266
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/1f2b512883ff/disk-93f5de5f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/e10aeb67696c/vmlinux-93f5de5f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/3e95be907cb0/bzImage-93f5de5f.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email-masked]

==================================================================
BUG: KCSAN: data-race in wg_packet_handshake_receive_worker / wg_packet_rx_poll

read-write to 0xffff88813939a178 of 8 bytes by interrupt on cpu 0:
 wg_packet_rx_poll+0xb43/0xf80 drivers/net/wireguard/receive.c:474
 __napi_poll+0x60/0x3b0 net/core/dev.c:6460
 napi_poll net/core/dev.c:6527 [inline]
 net_rx_action+0x32b/0x750 net/core/dev.c:6660
 __do_softirq+0xc1/0x265 kernel/softirq.c:553
 do_softirq+0x5e/0x90 kernel/softirq.c:454
 __local_bh_enable_ip+0x64/0x70 kernel/softirq.c:381
 __raw_spin_unlock_bh include/linux/spinlock_api_smp.h:167 [inline]
 _raw_spin_unlock_bh+0x36/0x40 kernel/locking/spinlock.c:210
 spin_unlock_bh include/linux/spinlock.h:396 [inline]
 ptr_ring_consume_bh include/linux/ptr_ring.h:367 [inline]
 wg_packet_handshake_receive_worker+0x184/0x5d0 drivers/net/wireguard/receive.c:212
 process_one_work+0x434/0x860 kernel/workqueue.c:2600
 worker_thread+0x5f2/0xa10 kernel/workqueue.c:2751
 kthread+0x1d7/0x210 kernel/kthread.c:389
 ret_from_fork+0x2e/0x40 arch/x86/kernel/process.c:145
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304

read-write to 0xffff88813939a178 of 8 bytes by task 8583 on cpu 1:
 update_rx_stats drivers/net/wireguard/receive.c:23 [inline]
 wg_receive_handshake_packet drivers/net/wireguard/receive.c:198 [inline]
 wg_packet_handshake_receive_worker+0x4b2/0x5d0 drivers/net/wireguard/receive.c:213
 process_one_work+0x434/0x860 kernel/workqueue.c:2600
 worker_thread+0x5f2/0xa10 kernel/workqueue.c:2751
 kthread+0x1d7/0x210 kernel/kthread.c:389
 ret_from_fork+0x2e/0x40 arch/x86/kernel/process.c:145
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304

value changed: 0x00000000000077a0 -> 0x00000000000077c0

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 8583 Comm: kworker/1:14 Tainted: G        W          6.5.0-rc7-syzkaller-00024-g93f5de5f648d #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
Workqueue: wg-kex-wg2 wg_packet_handshake_receive_worker
==================================================================

---
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 [email-masked].

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

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

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

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

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