Loopback transport coalesces some skbs too eagerly. Handling a zerocopy
(non-linear) skb as a linear one leads to skb data loss and kernel memory
disclosure.

Plug the loss/leak by allowing only linear skb join. Provide a test.

Signed-off-by: Michal Luczaj <mhal@rbox.co>
---
Michal Luczaj (2):
      vsock/virtio: Coalesce only linear skb
      vsock/test: Add test for a linear and non-linear skb getting coalesced

 net/vmw_vsock/virtio_transport_common.c   |  3 +-
 tools/testing/vsock/vsock_test.c          |  5 +++
 tools/testing/vsock/vsock_test_zerocopy.c | 67 +++++++++++++++++++++++++++++++
 tools/testing/vsock/vsock_test_zerocopy.h |  3 ++
 4 files changed, 77 insertions(+), 1 deletion(-)
---
base-commit: 653267321f05316f159e05b3ef562aa700632db6
change-id: 20260103-vsock-recv-coalescence-38178fafd10c

Best regards,
-- 
Michal Luczaj <mhal@rbox.co>

On 1/8/26 10:54, Michal Luczaj wrote:
> Loopback transport coalesces some skbs too eagerly. Handling a zerocopy
> (non-linear) skb as a linear one leads to skb data loss and kernel memory
> disclosure.
> 
> Plug the loss/leak by allowing only linear skb join. Provide a test.

Aaand I forgot to set the "net" prefix. Please let me know if I should
resend just for that.

Sorry,
Michal