Re: tun issue after e0b46d0ee9c: tun: Use iovec iterators
From: Herbert Xu <herbert@gondor.apana.org.au>
Date: 2014-11-30 10:03:34
Subsystem:
networking drivers, the rest, tun/tap driver · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds, Willem de Bruijn, Jason Wang
On Sat, Nov 29, 2014 at 07:59:35AM +0800, Herbert Xu wrote:
On Fri, Nov 28, 2014 at 05:25:27PM -0200, Marcelo Ricardo Leitner wrote:quoted
I saw there are tun updates on Dave's queue but none seemed to handle this. I can't use current net-next (799d2fff1858004526ad75d66a5dd8a5cce6ad40) on a kvm hypervisor because tun got clogged somehow. Bisected down to: commit e0b46d0ee9c240c7430a47e9b0365674d4a04522 Author: Herbert Xu [off-list ref] Date: Fri Nov 7 21:22:23 2014 +0800Does this patch help?
Oops, there was an embarrassing typo in the patch which causes
it to not even build. Here is the corrected version.
-- >8 --
Subject: tun: Fix GSO meta-data handling in tun_get_user
When we write the GSO meta-data in tun_get_user we end up advancing
the IO vector twice, thus exhausting the user buffer before we can
finish writing the packet.
Fixes: f5ff53b4d97c ("{macvtap,tun}_get_user(): switch to iov_iter")
Reported-by: Marcelo Ricardo Leitner <redacted>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 4b743c6..6d44da1 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c@@ -1052,7 +1052,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, if (gso.hdr_len > len) return -EINVAL; - iov_iter_advance(from, tun->vnet_hdr_sz); + iov_iter_advance(from, tun->vnet_hdr_sz - sizeof(gso)); } if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) {
Thanks, -- Email: Herbert Xu [off-list ref] Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt