Commit c7256f57 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller

tun: initialize napi_mutex unconditionally

This is the first part to fix following syzbot report :

console output: https://syzkaller.appspot.com/x/log.txt?x=145378e6400000
kernel config:  https://syzkaller.appspot.com/x/.config?x=443816db871edd66
dashboard link: https://syzkaller.appspot.com/bug?extid=e662df0ac1d753b57e80

Following patch is fixing the race condition, but it seems safer
to initialize this mutex at tfile creation anyway.

Fixes: 90e33d45 ("tun: enable napi_gro_frags() for TUN/TAP driver")
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Reported-by: syzbot+e662df0ac1d753b57e80@syzkaller.appspotmail.com
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 06e55add
......@@ -320,7 +320,6 @@ static void tun_napi_init(struct tun_struct *tun, struct tun_file *tfile,
netif_napi_add(tun->dev, &tfile->napi, tun_napi_poll,
NAPI_POLL_WEIGHT);
napi_enable(&tfile->napi);
mutex_init(&tfile->napi_mutex);
}
}
......@@ -3199,6 +3198,7 @@ static int tun_chr_open(struct inode *inode, struct file * file)
return -ENOMEM;
}
mutex_init(&tfile->napi_mutex);
RCU_INIT_POINTER(tfile->tun, NULL);
tfile->flags = 0;
tfile->ifindex = 0;
......
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