Re: [offlist] Re: Crash in netlink/sk_filter_trim_cap on ARMv7 on 4.18rc1

On Fri, Aug 17, 2018 at 02:40:19PM +0200, Daniel Borkmann wrote:

I'd have one potential bug suspicion, for the 4.18 one you were trying,
could you run with the below patch to see whether it would help?

I think this is almost certainly the problem - looking at the history,
it seems that the "-4" was assumed to be part of the scratch stuff in
commit 38ca93060163 ("bpf, arm32: save 4 bytes of unneeded stack space")
but it isn't - it's because "off" of zero refers to the top word in the
stack (iow at STACK_SIZE-4).

-- 
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