Re: [PATCH v2 net] wireguard: use DEV_STATS_INC()

[Hangbin Liu <liuhangbin@gmail.com>]

On Fri, Nov 17, 2023 at 02:17:33PM +0000, Eric Dumazet wrote:
> wg_xmit() can be called concurrently, KCSAN reported [1]
> some device stats updates can be lost.
> 
> Use DEV_STATS_INC() for this unlikely case.
> 
> [1]
> BUG: KCSAN: data-race in wg_xmit / wg_xmit
> 
> read-write to 0xffff888104239160 of 8 bytes by task 1375 on cpu 0:
> wg_xmit+0x60f/0x680 drivers/net/wireguard/device.c:231
> __netdev_start_xmit include/linux/netdevice.h:4918 [inline]
> netdev_start_xmit include/linux/netdevice.h:4932 [inline]
> xmit_one net/core/dev.c:3543 [inline]
> dev_hard_start_xmit+0x11b/0x3f0 net/core/dev.c:3559
> ...
> 
> read-write to 0xffff888104239160 of 8 bytes by task 1378 on cpu 1:
> wg_xmit+0x60f/0x680 drivers/net/wireguard/device.c:231
> __netdev_start_xmit include/linux/netdevice.h:4918 [inline]
> netdev_start_xmit include/linux/netdevice.h:4932 [inline]
> xmit_one net/core/dev.c:3543 [inline]
> dev_hard_start_xmit+0x11b/0x3f0 net/core/dev.c:3559
> ...
> 
> v2: also change wg_packet_consume_data_done() (Hangbin Liu)
>     and wg_packet_purge_staged_packets()
> 
> Fixes: e7096c131e51 ("net: WireGuard secure network tunnel")
> Reported-by: syzbot <syzkaller@googlegroups.com>
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> Cc: Jason A. Donenfeld <Jason@zx2c4.com>
> Cc: Hangbin Liu <liuhangbin@gmail.com>
> ---

I respect Jason's comments.

Reviewed-by: Hangbin Liu <liuhangbin@gmail.com>