net: stmmac: fix TSO header length truncation

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stmmac_tso_xmit() stores the protocol header length returned by
stmmac_tso_header_size() in a u8. stmmac_tso_valid_packet() admits
headers up to 1023 bytes, so a header longer than 255 bytes wraps modulo
256 (486 becomes 230, 256 becomes 0).

A TCP over IPv6 socket carrying a few hundred bytes of sticky
destination/hop-by-hop options makes skb_tcp_all_headers() exceed 255
while staying below the 1023-byte limit, so such an skb reaches
stmmac_tso_xmit().

Widen proto_hdr_len to unsigned int, which is sufficient since the value
is bounded by the hardware limit, and adjust the debug print specifier
accordingly.

Fixes: 9edfa7dab8 ("net: stmmac: enable TSO for IPv6")
Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@oss.qualcomm.com>
Reviewed-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Link: https://patch.msgid.link/20260911-stmmac-fix-header-length-v1-1-8fc103334327@oss.qualcomm.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

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Lorenzo Bianconi 2026-09-11 11:20:15 +02:00 • committed by Jakub Kicinski

parent 433cfc3025

commit 15989abd74

1 changed files with 3 additions and 3 deletions

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drivers/net/ethernet/stmicro/stmmac/stmmac_main.c

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