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Subject: Re: linux uml segfault
From: Johannes Berg <johannes@sipsolutions.net>
Date: Fri, 05 Mar 2021 11:07:48 +0100
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To: Anton Ivanov <anton.ivanov@kot-begemot.co.uk>, Benjamin Berg <benjamin@sipsolutions.net>, Hajime Tazaki <thehajime@gmail.com>
Cc: rrs@debian.org, chris.obbard@collabora.com, linux-um@lists.infradead.org, 983379@bugs.debian.org

On Fri, 2021-03-05 at 09:59 +0000, Anton Ivanov wrote:
> 
> This is proving very "interesting" to try to chase down, because the
> "picking the wrong library" does not happen every time.
> 
> F.E. yesterday my 5.10 builds were picking glibc memcpy and friends.
> Today with the same config and everything else the same it is picking
> built-ins.

Ouch.

> I need to finds some better way to reproduce this.

Maybe something like the original report? That caused sem_init() to be
called, so we know libc will/may call something there.

You and me probably don't have the nss setup to cause sem_init() to get
called, but maybe simply putting

void init_nss_interface(void)
{
  panic("how did we get here");
}

somewhere in the kernel image might already reproduce it?

johannes


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