linux-kernel - Re: [tip:x86/asmlinkage] lto: Handle LTO common symbols in module loader

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Message-ID: <87ios99y6u.fsf@rustcorp.com.au>
Date:	Fri, 21 Feb 2014 09:41:37 +1030
From:	Rusty Russell <rusty@...tcorp.com.au>
To:	mingo@...nel.org, hpa@...or.com, linux-kernel@...r.kernel.org,
	jmario@...hat.com, ak@...ux.intel.com, tglx@...utronix.de,
	hpa@...ux.intel.com, linux-tip-commits@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org, hpa@...or.com, mingo@...nel.org,
	jmario@...hat.com, ak@...ux.intel.com, tglx@...utronix.de,
	hpa@...ux.intel.com
Subject: Re: [tip:x86/asmlinkage] lto: Handle LTO common symbols in module loader

tip-bot for Joe Mario <tipbot@...or.com> writes:
> Commit-ID:  80375980f1608f43b47abc2671456b23ec68c434
> Gitweb:     http://git.kernel.org/tip/80375980f1608f43b47abc2671456b23ec68c434
> Author:     Joe Mario <jmario@...hat.com>
> AuthorDate: Sat, 8 Feb 2014 09:01:09 +0100
> Committer:  H. Peter Anvin <hpa@...ux.intel.com>
> CommitDate: Thu, 13 Feb 2014 20:24:50 -0800
>
> lto: Handle LTO common symbols in module loader
>
> Here is the workaround I made for having the kernel not reject modules
> built with -flto.  The clean solution would be to get the compiler to not
> emit the symbol.  Or if it has to emit the symbol, then emit it as
> initialized data but put it into a comdat/linkonce section.

Gah, as I said, fix the damn comment!

>  		case SHN_COMMON:
> +			/* Ignore common symbols */
> +			if (!strncmp(name, "__gnu_lto", 9))
> +				break;
> +
>  			/* We compiled with -fno-common.  These are not

/* Ignore common symbols */ is so bad, it's not even wrong.

Cheers,
Rusty.
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