* [MPTCP] [PATCH net] mptcp: sendmsg: reset iter on error
@ 2020-08-14 13:56 ` Florian Westphal
0 siblings, 0 replies; 6+ messages in thread
From: Florian Westphal @ 2020-08-14 13:56 UTC (permalink / raw)
To: mptcp
[-- Attachment #1: Type: text/plain, Size: 1505 bytes --]
Once we've copied data from the iterator we need to revert in case we
end up not sending any data.
This bug doesn't trigger with normal 'poll' based tests, because
we only feed a small chunk of data to kernel after poll indicated
POLLOUT. With blocking IO and large writes this triggers. Receiver
ends up with less data than it should get.
Fixes: 72511aab95c94d ("mptcp: avoid blocking in tcp_sendpages")
Signed-off-by: Florian Westphal <fw(a)strlen.de>
---
net/mptcp/protocol.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index d5aaa98b9136..2e7e87304930 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -725,8 +725,10 @@ static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk,
if (!psize)
return -EINVAL;
- if (!sk_wmem_schedule(sk, psize + dfrag->overhead))
+ if (!sk_wmem_schedule(sk, psize + dfrag->overhead)) {
+ iov_iter_revert(&msg->msg_iter, psize);
return -ENOMEM;
+ }
} else {
offset = dfrag->offset;
psize = min_t(size_t, dfrag->data_len, avail_size);
@@ -737,8 +739,10 @@ static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk,
*/
ret = do_tcp_sendpages(ssk, page, offset, psize,
msg->msg_flags | MSG_SENDPAGE_NOTLAST | MSG_DONTWAIT);
- if (ret <= 0)
+ if (ret <= 0) {
+ iov_iter_revert(&msg->msg_iter, psize);
return ret;
+ }
frag_truesize += ret;
if (!retransmission) {
--
2.26.2
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH net] mptcp: sendmsg: reset iter on error
@ 2020-08-14 13:56 ` Florian Westphal
0 siblings, 0 replies; 6+ messages in thread
From: Florian Westphal @ 2020-08-14 13:56 UTC (permalink / raw)
To: netdev; +Cc: mathew.j.martineau, matthieu.baerts, mptcp, Florian Westphal
Once we've copied data from the iterator we need to revert in case we
end up not sending any data.
This bug doesn't trigger with normal 'poll' based tests, because
we only feed a small chunk of data to kernel after poll indicated
POLLOUT. With blocking IO and large writes this triggers. Receiver
ends up with less data than it should get.
Fixes: 72511aab95c94d ("mptcp: avoid blocking in tcp_sendpages")
Signed-off-by: Florian Westphal <fw@strlen.de>
---
net/mptcp/protocol.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index d5aaa98b9136..2e7e87304930 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -725,8 +725,10 @@ static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk,
if (!psize)
return -EINVAL;
- if (!sk_wmem_schedule(sk, psize + dfrag->overhead))
+ if (!sk_wmem_schedule(sk, psize + dfrag->overhead)) {
+ iov_iter_revert(&msg->msg_iter, psize);
return -ENOMEM;
+ }
} else {
offset = dfrag->offset;
psize = min_t(size_t, dfrag->data_len, avail_size);
@@ -737,8 +739,10 @@ static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk,
*/
ret = do_tcp_sendpages(ssk, page, offset, psize,
msg->msg_flags | MSG_SENDPAGE_NOTLAST | MSG_DONTWAIT);
- if (ret <= 0)
+ if (ret <= 0) {
+ iov_iter_revert(&msg->msg_iter, psize);
return ret;
+ }
frag_truesize += ret;
if (!retransmission) {
--
2.26.2
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [MPTCP] Re: [PATCH net] mptcp: sendmsg: reset iter on error
2020-08-14 13:56 ` Florian Westphal
@ 2020-08-14 19:48 ` Mat Martineau
-1 siblings, 0 replies; 6+ messages in thread
From: Mat Martineau @ 2020-08-14 19:48 UTC (permalink / raw)
To: mptcp
[-- Attachment #1: Type: text/plain, Size: 726 bytes --]
On Fri, 14 Aug 2020, Florian Westphal wrote:
> Once we've copied data from the iterator we need to revert in case we
> end up not sending any data.
>
> This bug doesn't trigger with normal 'poll' based tests, because
> we only feed a small chunk of data to kernel after poll indicated
> POLLOUT. With blocking IO and large writes this triggers. Receiver
> ends up with less data than it should get.
>
> Fixes: 72511aab95c94d ("mptcp: avoid blocking in tcp_sendpages")
> Signed-off-by: Florian Westphal <fw(a)strlen.de>
> ---
> net/mptcp/protocol.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
Reviewed-by: Mat Martineau <mathew.j.martineau(a)linux.intel.com>
--
Mat Martineau
Intel
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH net] mptcp: sendmsg: reset iter on error
@ 2020-08-14 19:48 ` Mat Martineau
0 siblings, 0 replies; 6+ messages in thread
From: Mat Martineau @ 2020-08-14 19:48 UTC (permalink / raw)
To: Florian Westphal; +Cc: netdev, matthieu.baerts, mptcp
On Fri, 14 Aug 2020, Florian Westphal wrote:
> Once we've copied data from the iterator we need to revert in case we
> end up not sending any data.
>
> This bug doesn't trigger with normal 'poll' based tests, because
> we only feed a small chunk of data to kernel after poll indicated
> POLLOUT. With blocking IO and large writes this triggers. Receiver
> ends up with less data than it should get.
>
> Fixes: 72511aab95c94d ("mptcp: avoid blocking in tcp_sendpages")
> Signed-off-by: Florian Westphal <fw@strlen.de>
> ---
> net/mptcp/protocol.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
--
Mat Martineau
Intel
^ permalink raw reply [flat|nested] 6+ messages in thread
* [MPTCP] Re: [PATCH net] mptcp: sendmsg: reset iter on error
2020-08-14 13:56 ` Florian Westphal
@ 2020-08-14 21:12 ` David Miller
-1 siblings, 0 replies; 6+ messages in thread
From: David Miller @ 2020-08-14 21:12 UTC (permalink / raw)
To: mptcp
[-- Attachment #1: Type: text/plain, Size: 613 bytes --]
From: Florian Westphal <fw(a)strlen.de>
Date: Fri, 14 Aug 2020 15:56:34 +0200
> Once we've copied data from the iterator we need to revert in case we
> end up not sending any data.
>
> This bug doesn't trigger with normal 'poll' based tests, because
> we only feed a small chunk of data to kernel after poll indicated
> POLLOUT. With blocking IO and large writes this triggers. Receiver
> ends up with less data than it should get.
>
> Fixes: 72511aab95c94d ("mptcp: avoid blocking in tcp_sendpages")
> Signed-off-by: Florian Westphal <fw(a)strlen.de>
Applied and queued up for -stable, thanks.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH net] mptcp: sendmsg: reset iter on error
@ 2020-08-14 21:12 ` David Miller
0 siblings, 0 replies; 6+ messages in thread
From: David Miller @ 2020-08-14 21:12 UTC (permalink / raw)
To: fw; +Cc: netdev, mathew.j.martineau, matthieu.baerts, mptcp
From: Florian Westphal <fw@strlen.de>
Date: Fri, 14 Aug 2020 15:56:34 +0200
> Once we've copied data from the iterator we need to revert in case we
> end up not sending any data.
>
> This bug doesn't trigger with normal 'poll' based tests, because
> we only feed a small chunk of data to kernel after poll indicated
> POLLOUT. With blocking IO and large writes this triggers. Receiver
> ends up with less data than it should get.
>
> Fixes: 72511aab95c94d ("mptcp: avoid blocking in tcp_sendpages")
> Signed-off-by: Florian Westphal <fw@strlen.de>
Applied and queued up for -stable, thanks.
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2020-08-14 21:12 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
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2020-08-14 19:48 [MPTCP] Re: [PATCH net] mptcp: sendmsg: reset iter on error Mat Martineau
2020-08-14 19:48 ` Mat Martineau
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2020-08-14 21:12 [MPTCP] " David Miller
2020-08-14 21:12 ` David Miller
2020-08-14 13:56 [MPTCP] " Florian Westphal
2020-08-14 13:56 ` Florian Westphal
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