Re: [PATCH stable 3.10-3.16] tcp: Fix crash in TCP Fast Open
On Wed, Apr 15, 2015 at 07:00:32PM +0100, Ben Hutchings wrote: > Commit 355a901e6cf1 ("tcp: make connect() mem charging friendly") > changed tcp_send_syn_data() to perform an open-coded copy of the 'syn' > skb rather than using skb_copy_expand(). > > The open-coded copy does not cover the skb_shared_info::gso_segs > field, so in the new skb it is left set to 0. When this commit was > backported into stable branches between 3.10.y and 3.16.7-ckty > inclusive, it triggered the BUG() in tcp_transmit_skb(). > > Since Linux 3.18 the GSO segment count is kept in the > tcp_skb_cb::tcp_gso_segs field and tcp_send_syn_data() does copy the > tcp_skb_cb structure to the new skb, so mainline and newer stable > branches are not affected. > > Set skb_shared_info::gso_segs to the correct value of 1. > > Signed-off-by: Ben Hutchings > --- > net/ipv4/tcp_output.c | 1 + > 1 file changed, 1 insertion(+) Thanks for working on this and sending the patch out. greg k-h -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH stable 3.10-3.16] tcp: Fix crash in TCP Fast Open
On Wed, Apr 15, 2015 at 07:00:32PM +0100, Ben Hutchings wrote: > Commit 355a901e6cf1 ("tcp: make connect() mem charging friendly") > changed tcp_send_syn_data() to perform an open-coded copy of the 'syn' > skb rather than using skb_copy_expand(). > > The open-coded copy does not cover the skb_shared_info::gso_segs > field, so in the new skb it is left set to 0. When this commit was > backported into stable branches between 3.10.y and 3.16.7-ckty > inclusive, it triggered the BUG() in tcp_transmit_skb(). > > Since Linux 3.18 the GSO segment count is kept in the > tcp_skb_cb::tcp_gso_segs field and tcp_send_syn_data() does copy the > tcp_skb_cb structure to the new skb, so mainline and newer stable > branches are not affected. > > Set skb_shared_info::gso_segs to the correct value of 1. > > Signed-off-by: Ben Hutchings Thanks a lot, Ben. I'll queue this for the next 3.16 kernel release. Cheers, -- Luís > --- > net/ipv4/tcp_output.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c > index d5457e4..1ea0a07 100644 > --- a/net/ipv4/tcp_output.c > +++ b/net/ipv4/tcp_output.c > @@ -2992,6 +2992,7 @@ static int tcp_send_syn_data(struct sock *sk, struct > sk_buff *syn) > goto fallback; > syn_data->ip_summed = CHECKSUM_PARTIAL; > memcpy(syn_data->cb, syn->cb, sizeof(syn->cb)); > + skb_shinfo(syn_data)->gso_segs = 1; > if (unlikely(memcpy_fromiovecend(skb_put(syn_data, space), >fo->data->msg_iov, 0, space))) { > kfree_skb(syn_data); > > -- > Ben Hutchings > Editing code like this is akin to sticking plasters on the bleeding stump > of a severed limb. - me, 29 June 1999 -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH stable 3.10-3.16] tcp: Fix crash in TCP Fast Open
From: Eric Dumazet Date: Wed, 15 Apr 2015 11:22:44 -0700 > On Wed, 2015-04-15 at 19:00 +0100, Ben Hutchings wrote: >> Commit 355a901e6cf1 ("tcp: make connect() mem charging friendly") >> changed tcp_send_syn_data() to perform an open-coded copy of the 'syn' >> skb rather than using skb_copy_expand(). >> >> The open-coded copy does not cover the skb_shared_info::gso_segs >> field, so in the new skb it is left set to 0. When this commit was >> backported into stable branches between 3.10.y and 3.16.7-ckty >> inclusive, it triggered the BUG() in tcp_transmit_skb(). >> >> Since Linux 3.18 the GSO segment count is kept in the >> tcp_skb_cb::tcp_gso_segs field and tcp_send_syn_data() does copy the >> tcp_skb_cb structure to the new skb, so mainline and newer stable >> branches are not affected. >> >> Set skb_shared_info::gso_segs to the correct value of 1. >> >> Signed-off-by: Ben Hutchings ... > Looks goot to me, thanks Ben ! > > Acked-by: Eric Dumazet Ben, thanks for taking care of this. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH stable 3.10-3.16] tcp: Fix crash in TCP Fast Open
On Wed, 2015-04-15 at 19:00 +0100, Ben Hutchings wrote: > Commit 355a901e6cf1 ("tcp: make connect() mem charging friendly") > changed tcp_send_syn_data() to perform an open-coded copy of the 'syn' > skb rather than using skb_copy_expand(). > > The open-coded copy does not cover the skb_shared_info::gso_segs > field, so in the new skb it is left set to 0. When this commit was > backported into stable branches between 3.10.y and 3.16.7-ckty > inclusive, it triggered the BUG() in tcp_transmit_skb(). > > Since Linux 3.18 the GSO segment count is kept in the > tcp_skb_cb::tcp_gso_segs field and tcp_send_syn_data() does copy the > tcp_skb_cb structure to the new skb, so mainline and newer stable > branches are not affected. > > Set skb_shared_info::gso_segs to the correct value of 1. > > Signed-off-by: Ben Hutchings > --- > net/ipv4/tcp_output.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c > index d5457e4..1ea0a07 100644 > --- a/net/ipv4/tcp_output.c > +++ b/net/ipv4/tcp_output.c > @@ -2992,6 +2992,7 @@ static int tcp_send_syn_data(struct sock *sk, struct > sk_buff *syn) > goto fallback; > syn_data->ip_summed = CHECKSUM_PARTIAL; > memcpy(syn_data->cb, syn->cb, sizeof(syn->cb)); > + skb_shinfo(syn_data)->gso_segs = 1; > if (unlikely(memcpy_fromiovecend(skb_put(syn_data, space), >fo->data->msg_iov, 0, space))) { > kfree_skb(syn_data); > Looks goot to me, thanks Ben ! Acked-by: Eric Dumazet -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
[PATCH stable 3.10-3.16] tcp: Fix crash in TCP Fast Open
Commit 355a901e6cf1 ("tcp: make connect() mem charging friendly") changed tcp_send_syn_data() to perform an open-coded copy of the 'syn' skb rather than using skb_copy_expand(). The open-coded copy does not cover the skb_shared_info::gso_segs field, so in the new skb it is left set to 0. When this commit was backported into stable branches between 3.10.y and 3.16.7-ckty inclusive, it triggered the BUG() in tcp_transmit_skb(). Since Linux 3.18 the GSO segment count is kept in the tcp_skb_cb::tcp_gso_segs field and tcp_send_syn_data() does copy the tcp_skb_cb structure to the new skb, so mainline and newer stable branches are not affected. Set skb_shared_info::gso_segs to the correct value of 1. Signed-off-by: Ben Hutchings --- net/ipv4/tcp_output.c | 1 + 1 file changed, 1 insertion(+) diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index d5457e4..1ea0a07 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -2992,6 +2992,7 @@ static int tcp_send_syn_data(struct sock *sk, struct sk_buff *syn) goto fallback; syn_data->ip_summed = CHECKSUM_PARTIAL; memcpy(syn_data->cb, syn->cb, sizeof(syn->cb)); + skb_shinfo(syn_data)->gso_segs = 1; if (unlikely(memcpy_fromiovecend(skb_put(syn_data, space), fo->data->msg_iov, 0, space))) { kfree_skb(syn_data); -- Ben Hutchings Editing code like this is akin to sticking plasters on the bleeding stump of a severed limb. - me, 29 June 1999 signature.asc Description: This is a digitally signed message part