Subject: [syzbot] [wireguard?] KCSAN: data-race in wg_packet_handshake_receive_worker / wg_packet_rx_poll (7)

From: syzbot <[email-masked]>
Date: Fri, 12 Jan 2024 02:10:28 -0800

Hello,

syzbot found the following issue on:

HEAD commit:    5db8752c3b81 Merge tag 'vfs-6.8.iov_iter' of git://git.ker..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1540e665e80000
kernel config:  https://syzkaller.appspot.com/x/.config?x=d7a01358d18c37d5
dashboard link: https://syzkaller.appspot.com/bug?extid=97d9596e4ae0572c9825
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/0636ecefd856/disk-5db8752c.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/cc253e77814b/vmlinux-5db8752c.xz
kernel image: https://storage.googleapis.com/syzbot-assets/63071c2b09b4/bzImage-5db8752c.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 0xffff88812def3390 of 8 bytes by interrupt on cpu 1:
 update_rx_stats drivers/net/wireguard/receive.c:23 [inline]
 wg_packet_consume_data_done drivers/net/wireguard/receive.c:412 [inline]
 wg_packet_rx_poll+0xbd3/0xf00 drivers/net/wireguard/receive.c:474
 __napi_poll+0x60/0x3b0 net/core/dev.c:6536
 napi_poll net/core/dev.c:6605 [inline]
 net_rx_action+0x32b/0x750 net/core/dev.c:6738
 __do_softirq+0xc4/0x279 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_decrypt_worker+0x6c5/0x700 drivers/net/wireguard/receive.c:499
 process_one_work kernel/workqueue.c:2627 [inline]
 process_scheduled_works+0x5b8/0xa30 kernel/workqueue.c:2700
 worker_thread+0x525/0x730 kernel/workqueue.c:2781
 kthread+0x1d7/0x210 kernel/kthread.c:388
 ret_from_fork+0x48/0x60 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242

read-write to 0xffff88812def3390 of 8 bytes by task 8602 on cpu 0:
 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+0x4b9/0x5e0 drivers/net/wireguard/receive.c:213
 process_one_work kernel/workqueue.c:2627 [inline]
 process_scheduled_works+0x5b8/0xa30 kernel/workqueue.c:2700
 worker_thread+0x525/0x730 kernel/workqueue.c:2781
 kthread+0x1d7/0x210 kernel/kthread.c:388
 ret_from_fork+0x48/0x60 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242

value changed: 0x000000000000079c -> 0x00000000000007ec

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 8602 Comm: kworker/0:0 Tainted: G        W          6.7.0-syzkaller-00119-g5db8752c3b81 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
Workqueue: wg-kex-wg1 wg_packet_handshake_receive_worker
==================================================================

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