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| author | Norbert Szetei <norbert@doyensec.com> | 2026-08-22 11:15:08 +0200 |
|---|---|---|
| committer | Paolo Abeni <pabeni@redhat.com> | 2026-08-25 09:36:47 +0200 |
| commit | f66bdb1cc0fcd227a062378f8be0b5873aa5600a (patch) | |
| tree | 94b502dd3b5e9f9b0f6245449062da1ee8776964 /net | |
| parent | 8ece906150128d5ec2462aabcc978c568433eca4 (diff) | |
| download | linux-f66bdb1cc0fcd227a062378f8be0b5873aa5600a.tar.gz linux-f66bdb1cc0fcd227a062378f8be0b5873aa5600a.zip | |
net: skbuff: don't touch shared zerocopy state in skb_tx_error()
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: stable@vger.kernel.org
Suggested-by: Ilya Maximets <i.maximets@ovn.org>
Signed-off-by: Norbert Szetei <norbert@doyensec.com>
Reviewed-by: Ilya Maximets <i.maximets@ovn.org>
Tested-by: Jongmin Jang <payload.jang@gmail.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/CFAB292A-674B-4C14-BB2C-BB8830AD5659@doyensec.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Diffstat (limited to 'net')
| -rw-r--r-- | net/core/skbuff.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/net/core/skbuff.c b/net/core/skbuff.c index ab3d161247b9..b9541329f1a7 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -1417,10 +1417,13 @@ 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) { - if (skb) { + if (skb && !skb_cloned(skb)) { skb_zcopy_downgrade_managed(skb); skb_zcopy_clear(skb, true); } |