RE: [PATCH v6 00/13] Add build ID to stacktraces

From: David Laight <David.Laight@ACULAB.COM>
To: 'Petr Mladek' <pmladek@suse.com>
Cc: 'Steven Rostedt' <rostedt@goodmis.org>,
	'Stephen Boyd' <swboyd@chromium.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"Alexei Starovoitov" <ast@kernel.org>,
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	Baoquan He <bhe@redhat.com>, "Borislav Petkov" <bp@alien8.de>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Dave Young <dyoung@redhat.com>, Evan Green <evgreen@chromium.org>,
	Hsin-Yi Wang <hsinyi@chromium.org>,
	Ingo Molnar <mingo@redhat.com>, Jessica Yu <jeyu@kernel.org>,
	Jiri Olsa <jolsa@kernel.org>,
	"kexec@lists.infradead.org" <kexec@lists.infradead.org>,
	Konstantin Khlebnikov <khlebnikov@yandex-team.ru>,
	"linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>,
	"linux-doc@vger.kernel.org" <linux-doc@vger.kernel.org>,
	Matthew Wilcox <willy@infradead.org>,
	"Rasmus Villemoes" <linux@rasmusvillemoes.dk>,
	Sasha Levin <sashal@kernel.org>,
	Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Vivek Goyal <vgoyal@redhat.com>, Will Deacon <will@kernel.org>,
	"x86@kernel.org" <x86@kernel.org>,
	Christoph Hellwig <hch@infradead.org>,
	peter enderborg <peter.enderborg@sony.com>
Subject: RE: [PATCH v6 00/13] Add build ID to stacktraces
Date: Tue, 11 May 2021 14:31:38 +0000	[thread overview]
Message-ID: <f09e9d68e4b14de58e881050a3c78ec1@AcuMS.aculab.com> (raw)
In-Reply-To: <YJqTB5pJiRqS1yGY@alley>

From: Petr Mladek
> Sent: 11 May 2021 15:22
> 
> On Tue 2021-05-11 12:58:47, David Laight wrote:
> > From: Steven Rostedt
> > > Sent: 11 May 2021 13:53
> > >
> > > On Tue, 11 May 2021 12:36:06 +0000
> > > David Laight <David.Laight@ACULAB.COM> wrote:
> > >
> > > > >  x1 : ffffff93fef15788 x0 : ffffffe3622352e0
> > > > >  Call trace:
> > > > >   lkdtm_WARNING+0x28/0x30 [lkdtm ed5019fdf5e53be37cb1ba7899292d7e143b259e]
> > > > >   direct_entry+0x16c/0x1b4 [lkdtm ed5019fdf5e53be37cb1ba7899292d7e143b259e]
> > > > >   full_proxy_write+0x74/0xa4
> > > >
> > > > Is there any way to get it to print each module ID only once?
> > >
> > > If there's a trivial way to do that, then perhaps it should be done, but for
> > > now, this patch series isn't as obnoxious as the previous versions. It only
> > > affects stack traces, and I'm fine with that.
> >
> > True. Printing the id in the module list was horrid.
> >
> > The real downside is all the extra text that will overflow the
> > in-kernel buffer.
> > At least it shouldn't be extra lines causing screen wrap.
> > Unless the variable names are long - hi rust :-)
> 
> Note that the ID is printed only when CONFIG_STACKTRACE_BUILD_ID
> is enabled. It will be used only by some distros/vendors that
> use it to download the debuginfo packages.

Until Ubuntu decide to turn it on :-)

Actually, for the use case, the id could be trimmed significantly.
It is only trying to differentiate between builds of a specific module.
So even 8 digits would be plenty.

	David

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