Re: [PATCH 1/3] packfile: factor out --pack_header argument parsing

From: Koakuma <koachan@protonmail.com>
Date: Jan 18, 2025, 16:57 UTC
Message-ID: <oyahQoMDgyHL5zm-JuAtwlkUM2gHqO67zs83WP5Cm2h07S0x_xt8m4CNiShDFe2epznxlJF3kC-X_g414dRhDdrko44xo_yfsDXq1esVYVo=@protonmail.com>
In-Reply-To: <20250118092351.GB3474411@coredump.intra.peff.net>

Jeff King <peff@peff.net> wrote:

Show 19 quoted lines

> Junio C Hamano wrote:
> > Jeff King peff@peff.net writes:
> > Interesting. So the file-scope static input_buffer[] sits in the
> > BSS and happens to be well aligned not to cause the problem, but ...
> 
> I suspect it is a problem, but either:
> 
> - The OP's test case was small enough to trigger unpack-objects, not
> index-pack. Possibly:
> 
> git index-pack --stdin --pack_header=2,2 <no-header.pack
> 
> would fail for them.
> 
> - We simply got lucky with alignment based on the other things in BSS,
> the whim of the compiler, etc. But it is an accident waiting to
> happen.
> 
> -Peff

That particular command doesn't seem to crash for me right now, but, as you said, that is probably just a lucky coincidence that the compiler happens to place the buffer on aligned memory.