From mboxrd@z Thu Jan  1 00:00:00 1970
From: Eric Dumazet <eric.dumazet@gmail.com>
Subject: Re: UBSAN reports issue in ip_idents_reserve
Date: Tue, 20 Sep 2016 07:11:51 -0700
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To: Jiri Pirko <jiri@resnulli.us>
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On Tue, 2016-09-20 at 15:39 +0200, Jiri Pirko wrote:

> I see. So how to silent the warning?
> 

We can replace the atomic_add_return() and use a loop around
atomic_read() and atomic_cmpxhg()

This would change the nice property of x86 xadd into a loop.

Or we also could fallback to random generation if the atomic_cmpxchg()
fails.

I'll provide a patch, thanks.