On Fri, 13 Jun 2025 04:28:01 +0000 Mina Almasry wrote:
skb_ensure_writable actually makes sure that the header of the skb is writable, and doesn't touch the payload. It doesn't need an skb_frags_readable check.
"doesn't touch the payload" is a bit misleading. What I'd say instead is that the pskb_may_pull() call about ensures that write_len is within the head, and will already fail if write_len would dip into unreadable frags.
Removing this check restores DSCP functionality with unreadable skbs as it's called from dscp_tg.
Fixes: 65249feb6b3d ("net: add support for skbs with unreadable frags")
Signed-off-by: Mina Almasry almasrymina@google.com
Either no Fixes tag or send it to net. I think net is fine, this is clearly incorrect. By definition devmem should not prevent header modifications, so net?
nit: no empty lines between tags