Subject: Re: [bpf, xdp] headroom - was: Re: Question about to KMSAN: uninit-value in can_receive

From: Jakub Kicinski <[email-masked]>
Date: Fri, 2 Jan 2026 12:04:05 -0800

On Fri, 2 Jan 2026 21:06:11 +0530 Prithvi wrote:
> Just a gentle ping on this thread 

You're asking the wrong person, IIUC Andrii is tangentially involved
in XDP (via bpf links?):

XDP (eXpress Data Path)
M:	Alexei Starovoitov <[email-masked]>
M:	Daniel Borkmann <[email-masked]>
M:	David S. Miller <[email-masked]>
M:	Jakub Kicinski <[email-masked]>
M:	Jesper Dangaard Brouer <[email-masked]>
M:	John Fastabend <[email-masked]>
R:	Stanislav Fomichev <[email-masked]>
L:	[email-masked]
L:	[email-masked]

Without looking too deeply - XDP has historically left the new space
uninitialized after push, expecting programs to immediately write the
headers in that space. syzbot had run into this in the past but I can't
find any references to past threads quickly :(