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From: Petr Mladek <pmladek@suse.com>
To: Song Liu <songliubraving@meta.com>
Cc: zhang warden <zhangwarden@gmail.com>,
	Steven Rostedt <rostedt@goodmis.org>, Song Liu <song@kernel.org>,
	"live-patching@vger.kernel.org" <live-patching@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	"linux-trace-kernel@vger.kernel.org"
	<linux-trace-kernel@vger.kernel.org>,
	Josh Poimboeuf <jpoimboe@kernel.org>,
	Jiri Kosina <jikos@kernel.org>, Miroslav Benes <mbenes@suse.cz>,
	Joe Lawrence <joe.lawrence@redhat.com>,
	Nathan Chancellor <nathan@kernel.org>,
	"morbo@google.com" <morbo@google.com>,
	Justin Stitt <justinstitt@google.com>,
	Luis Chamberlain <mcgrof@kernel.org>,
	Leizhen <thunder.leizhen@huawei.com>,
	"kees@kernel.org" <kees@kernel.org>,
	Kernel Team <kernel-team@meta.com>,
	Matthew Maurer <mmaurer@google.com>,
	Sami Tolvanen <samitolvanen@google.com>,
	Masami Hiramatsu <mhiramat@kernel.org>
Subject: Re: [PATCH v2 3/3] tracing/kprobes: Use APIs that matches symbols without .XXX suffix
Date: Thu, 8 Aug 2024 11:48:33 +0200	[thread overview]
Message-ID: <ZrSUcbOtNc18D8ax@pathway.suse.cz> (raw)
In-Reply-To: <22D3CE6E-945B-43C4-A3A2-C57588B12BD0@fb.com>

On Wed 2024-08-07 19:46:31, Song Liu wrote:
> 
> 
> > On Aug 7, 2024, at 7:58 AM, zhang warden <zhangwarden@gmail.com> wrote:
> > 
> > 
> >> In my GCC built, we have suffixes like ".constprop.0", ".part.0", ".isra.0", 
> >> and ".isra.0.cold".
> > 
> > A fresher's eye, I met sometime when try to build a livepatch module and found some mistake caused by ".constprop.0" ".part.0" which is generated by GCC.
> > 
> > These section with such suffixes is special and sometime the symbol st_value is quite different. What is these kind of section (or symbol) use for?
> 
> 
> IIUC, constprop means const propagation. For example, function 
> "foo(int a, int b)" that is called as "foo(a, 10)" will be come 
> "foo(int a)" with a hard-coded b = 10 inside. 
> 
> .part.0 is part of the function, as the other part is inlined in 
> the caller. 

Hmm, we should not remove the suffixes like .constprop*, .part*,
.isra*. They implement a special optimized variant of the function.
It is not longer the original full-featured one.

This is a difference against adding a suffix for a static function.
Such a symbol implements the original full-featured function.

Best Regards,
Petr

  parent reply	other threads:[~2024-08-08  9:48 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-08-02 21:08 [PATCH v2 0/3] Fix kallsyms with CONFIG_LTO_CLANG Song Liu
2024-08-02 21:08 ` [PATCH v2 1/3] kallsyms: Do not cleanup .llvm.<hash> suffix before sorting symbols Song Liu
2024-08-02 21:08 ` [PATCH v2 2/3] kallsyms: Add APIs to match symbol without .XXXX suffix Song Liu
2024-08-05 13:45   ` Masami Hiramatsu
2024-08-05 17:46     ` Song Liu
2024-08-08 10:20   ` Petr Mladek
2024-08-08 15:13     ` Song Liu
2024-08-02 21:08 ` [PATCH v2 3/3] tracing/kprobes: Use APIs that matches symbols without .XXX suffix Song Liu
2024-08-06 18:44   ` Steven Rostedt
2024-08-06 19:35     ` Song Liu
2024-08-06 20:00       ` Steven Rostedt
2024-08-06 20:01         ` Steven Rostedt
2024-08-06 20:12           ` Song Liu
2024-08-07  0:01             ` Masami Hiramatsu
2024-08-07  0:19               ` Song Liu
2024-08-07 10:08                 ` Masami Hiramatsu
2024-08-07 15:33                   ` Sami Tolvanen
2024-08-07 20:48                     ` Song Liu
2024-08-08  9:59                       ` Petr Mladek
2024-08-08 15:20                         ` Song Liu
2024-08-09 15:40                           ` Petr Mladek
2024-08-09 16:33                             ` Song Liu
2024-08-08 15:52                         ` Masami Hiramatsu
2024-08-09  6:20                         ` Alessandro Carminati
2024-08-09 16:40                           ` Song Liu
2024-08-07 21:26                     ` Masami Hiramatsu
2024-08-07 19:41                   ` Song Liu
2024-08-07 20:08                     ` Steven Rostedt
2024-08-07 20:40                       ` Song Liu
2024-08-07 20:43                         ` Song Liu
2024-08-07 20:55                 ` Masami Hiramatsu
2024-08-07 21:07                   ` Song Liu
2024-08-07 14:58             ` zhang warden
2024-08-07 19:46               ` Song Liu
2024-08-08  2:10                 ` zhang warden
2024-08-08  9:48                 ` Petr Mladek [this message]
2024-08-08 15:17                   ` Song Liu

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