[Intel-wired-lan] [PATCH bpf v2 4/9] ice: change XDP RxQ frag_size from DMA write length to xdp.frame_sz

[Loktionov, Aleksandr]

> -----Original Message-----
> From: Zaremba, Larysa <larysa.zaremba at intel.com>
> Sent: Thursday, February 12, 2026 7:33 PM
> To: bpf at vger.kernel.org
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> Aleksandr <aleksandr.loktionov at intel.com>; Dragos Tatulea
> <dtatulea at nvidia.com>
> Subject: [PATCH bpf v2 4/9] ice: change XDP RxQ frag_size from DMA
> write length to xdp.frame_sz
> 
> The only user of frag_size field in XDP RxQ info is
> bpf_xdp_frags_increase_tail(). It clearly expects whole buff size
> instead of DMA write size. Different assumptions in ice driver
> configuration lead to negative tailroom.
> 
> This allows to trigger kernel panic, when using
> XDP_ADJUST_TAIL_GROW_MULTI_BUFF xskxceiver test and changing packet
> size to
> 6912 and the requisted offset to a huge value, e.g.

"requisted offset" -> "requested offset"

Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov at intel.com>
> XSK_UMEM__MAX_FRAME_SIZE * 100.
> 
> Due to other quirks of the ZC configuration in ice, panic is not
> observed in ZC mode, but tailroom growing still fails when it should
> not.
> 
> Use fill queue buffer truesize instead of DMA write size in XDP RxQ
> info.
> Fix ZC mode too by using the new helper.
> 
> Fixes: 2fba7dc5157b ("ice: Add support for XDP multi-buffer on Rx
> side")
> Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov at intel.com>
> Signed-off-by: Larysa Zaremba <larysa.zaremba at intel.com>
> ---

...
 
> --
> 2.52.0