diff mbox series

[v3,2/2] QIOChannelSocket: Fix zero-copy send so socket flush works

Message ID 20220614051725.143985-2-leobras@redhat.com (mailing list archive)
State New, archived
Headers show
Series [v3,1/2] QIOChannelSocket: Introduce assert and reduce ifdefs to improve readability | expand

Commit Message

Leonardo Bras June 14, 2022, 5:17 a.m. UTC
Somewhere between v6 and v7 the of the zero-copy-send patchset a crucial
part of the flushing mechanism got missing: incrementing zero_copy_queued.

Without that, the flushing interface becomes a no-op, and there is no
guarantee the buffer is really sent.

This can go as bad as causing a corruption in RAM during migration.

Fixes: 2bc58ffc2926 ("QIOChannelSocket: Implement io_writev zero copy flag & io_flush for CONFIG_LINUX")
Reported-by: 徐闯 <xuchuangxclwt@bytedance.com>
Signed-off-by: Leonardo Bras <leobras@redhat.com>
---
 io/channel-socket.c | 5 +++++
 1 file changed, 5 insertions(+)

Comments

Daniel P. Berrangé June 14, 2022, 8:38 a.m. UTC | #1
On Tue, Jun 14, 2022 at 02:17:26AM -0300, Leonardo Bras wrote:
> Somewhere between v6 and v7 the of the zero-copy-send patchset a crucial
> part of the flushing mechanism got missing: incrementing zero_copy_queued.
> 
> Without that, the flushing interface becomes a no-op, and there is no
> guarantee the buffer is really sent.
> 
> This can go as bad as causing a corruption in RAM during migration.
> 
> Fixes: 2bc58ffc2926 ("QIOChannelSocket: Implement io_writev zero copy flag & io_flush for CONFIG_LINUX")
> Reported-by: 徐闯 <xuchuangxclwt@bytedance.com>
> Signed-off-by: Leonardo Bras <leobras@redhat.com>
> ---
>  io/channel-socket.c | 5 +++++
>  1 file changed, 5 insertions(+)

Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>


With regards,
Daniel
diff mbox series

Patch

diff --git a/io/channel-socket.c b/io/channel-socket.c
index cdce7b0b45..f31dd189a5 100644
--- a/io/channel-socket.c
+++ b/io/channel-socket.c
@@ -607,6 +607,11 @@  static ssize_t qio_channel_socket_writev(QIOChannel *ioc,
                          "Unable to write to socket");
         return -1;
     }
+
+    if (flags & QIO_CHANNEL_WRITE_FLAG_ZERO_COPY) {
+        sioc->zero_copy_queued++;
+    }
+
     return ret;
 }
 #else /* WIN32 */