linux-kernel - Re: [PATCH v3 2/2] kallsyms: Match symbols exactly with CONFIG_LTO

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Message-ID: <7E4D8E14-6FFF-4A40-A29B-4DC48F5DDD28@fb.com>
Date: Tue, 13 Aug 2024 21:16:59 +0000
From: Song Liu <songliubraving@...a.com>
To: Song Liu <song@...nel.org>
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Subject: Re: [PATCH v3 2/2] kallsyms: Match symbols exactly with
 CONFIG_LTO_CLANG



> On Aug 7, 2024, at 3:05 PM, Song Liu <song@...nel.org> wrote:
> 
> With CONFIG_LTO_CLANG=y, the compiler may add .llvm.<hash> suffix to
> function names to avoid duplication. APIs like kallsyms_lookup_name()
> and kallsyms_on_each_match_symbol() tries to match these symbol names
> without the .llvm.<hash> suffix, e.g., match "c_stop" with symbol
> c_stop.llvm.17132674095431275852. This turned out to be problematic
> for use cases that require exact match, for example, livepatch.
> 
> Fix this by making the APIs to match symbols exactly.
> 
> Also cleanup kallsyms_selftests accordingly.
> 
> Signed-off-by: Song Liu <song@...nel.org>

Fixes: 8cc32a9bbf29 ("kallsyms: strip LTO-only suffixes from promoted global functions")