5.15-stable review patch. If anyone has any objections, please let me know.
------------------
From: Norbert Szetei <redacted>
[ Upstream commit f66bdb1cc0fcd227a062378f8be0b5873aa5600a ]
skb_tx_error() completes the zerocopy uarg and clears
SKBFL_ALL_ZEROCOPY, and skb_zcopy_downgrade_managed() clears
SKBFL_MANAGED_FRAG_REFS. Both live in skb_shinfo(), which every clone
shares, while the caller only owns the reference it is about to drop.
Through a clone it tells the producer its pages are free and drops
SKBFL_SHARED_FRAG for an skb that is still in flight.
Open vSwitch reaches this with a non-last OVS_ACTION_ATTR_RECIRC:
clone_execute() sends a skb_clone() into ovs_dp_process_packet() while
do_execute_actions() keeps forwarding the original, and skb_clone()
does not privatise the frags here -- skb_orphan_frags() returns early
on SKBFL_DONT_ORPHAN. A flow miss on the clone then strips the marker
from the packet still being forwarded, and a later local ESP delivery
decrypts in place over frags it does not own privately.
Skip it for a cloned skb. Nothing is lost: skb_release_data() clears
the zerocopy state once the last reference to the shared data goes.
Fixes: 25121173f7b1 ("skb: api to report errors for zero copy skbs")
Cc: <redacted>
Suggested-by: Ilya Maximets <i.maximets@ovn.org>
Signed-off-by: Norbert Szetei <redacted>
Reviewed-by: Ilya Maximets <i.maximets@ovn.org>
Tested-by: Jongmin Jang <redacted>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/CFAB292A-674B-4C14-BB2C-BB8830AD5659@doyensec.com (local)
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
[ There was no 'if' on 5.x as there is no skb_zcopy_downgrade_managed(). ]
Signed-off-by: Ilya Maximets <i.maximets@ovn.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/core/skbuff.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 6281cfed03bb2..83ad581b12fa9 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -889,10 +889,14 @@ EXPORT_SYMBOL(skb_dump);
*
* Report xmit error if a device callback is tracking this skb.
* skb must be freed afterwards.
+ *
+ * Does nothing for a cloned skb: the zerocopy state lives in
+ * skb_shinfo(), which the clones share.
*/
void skb_tx_error(struct sk_buff *skb)
{
- skb_zcopy_clear(skb, true);
+ if (skb && !skb_cloned(skb))
+ skb_zcopy_clear(skb, true);
}
EXPORT_SYMBOL(skb_tx_error);
--
2.53.0