xsk: avoid skb leak in XDP_TX_METADATA case

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Fix it by explicitly adding kfree_skb() before returning back to its
caller.

How to reproduce it in virtio_net:
1. the current skb is the first one (which means no frag and xs->skb is
   NULL) and users enable metadata feature.
2. xsk_skb_metadata() returns a error code.
3. the caller xsk_build_skb() clears skb by using 'skb = NULL;'.
4. there is no chance to free this skb anymore.

Closes: https://lore.kernel.org/all/20260415085204.3F87AC19424@smtp.kernel.org/
Fixes: 30c3055f9c ("xsk: wrap generic metadata handling onto separate function")
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Signed-off-by: Jason Xing <kernelxing@tencent.com>
Reviewed-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Link: https://patch.msgid.link/20260502200722.53960-7-kerneljasonxing@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

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Jason Xing 2026-05-02 23:07:20 +03:00 • committed by Jakub Kicinski

parent 3dec153ae4

commit 8c2cff50af

1 changed files with 3 additions and 1 deletions

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net/xdp/xsk.c

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