From: Stephen Boyd <swboyd@chromium.org>
To: Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
Jessica Yu <jeyu@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org, Jiri Olsa <jolsa@kernel.org>,
Alexei Starovoitov <ast@kernel.org>,
Evan Green <evgreen@chromium.org>,
Hsin-Yi Wang <hsinyi@chromium.org>,
Petr Mladek <pmladek@suse.com>,
Steven Rostedt <rostedt@goodmis.org>,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
Rasmus Villemoes <linux@rasmusvillemoes.dk>,
linux-doc@vger.kernel.org, Matthew Wilcox <willy@infradead.org>
Subject: Re: [PATCH v3 04/12] module: Add printk format to add module build ID to stacktraces
Date: Thu, 08 Apr 2021 12:57:08 -0700 [thread overview]
Message-ID: <161791182832.3790633.9176764008911708133@swboyd.mtv.corp.google.com> (raw)
In-Reply-To: <YG8NwgD3y/ydzVXI@smile.fi.intel.com>
Quoting Andy Shevchenko (2021-04-08 07:05:54)
> On Thu, Apr 08, 2021 at 03:44:57PM +0200, Jessica Yu wrote:
> > +++ Stephen Boyd [30/03/21 20:05 -0700]:
>
> ...
>
> > > +static void init_build_id(struct module *mod, const struct load_info *info)
> > > +{
> > > + const Elf_Shdr *sechdr;
> > > + unsigned int i;
> > > +
> > > + for (i = 0; i < info->hdr->e_shnum; i++) {
> > > + sechdr = &info->sechdrs[i];
> > > + if (!sect_empty(sechdr) && sechdr->sh_type == SHT_NOTE &&
> > > + !build_id_parse_buf((void *)sechdr->sh_addr, mod->build_id,
> > > + sechdr->sh_size))
> > > + break;
> > > + }
> > > +}
> >
> > Why not just look for the .note.gnu.build-id section instead of trying
> > to parse each note section? Doesn't it always contain the build id? At
> > least the ld man page seems to suggest this section name should be
> > consistent.
That's basically what this code is doing. We're looking through all the
section headers and finding the ones that are notes and then
build_id_parse_buf() is checking to see if that note is a GNU type note
(name == "GNU") and is of the type NT_GNU_BUILD_ID (type == 3). We don't
need to check for a section name of ".note.gnu.build-id", we can use the
existing code in build_id_parse_buf() that looks for the name and type.
>
> Interesting idea (in positive way!), I'm wondering what Clang does in such
> case.
>
Clang also inserts a GNU build ID and it works with these patches.
next prev parent reply other threads:[~2021-04-08 19:57 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-31 3:05 [PATCH v3 00/12] Add build ID to stacktraces Stephen Boyd
2021-03-31 3:05 ` [PATCH v3 01/12] buildid: Add API to parse build ID out of buffer Stephen Boyd
2021-03-31 3:05 ` [PATCH v3 02/12] buildid: Stash away kernels build ID on init Stephen Boyd
2021-04-08 12:05 ` Jessica Yu
2021-04-08 18:52 ` Stephen Boyd
2021-03-31 3:05 ` [PATCH v3 03/12] dump_stack: Add vmlinux build ID to stack traces Stephen Boyd
2021-04-07 13:42 ` Petr Mladek
2021-04-08 5:44 ` Stephen Boyd
2021-04-07 14:03 ` Petr Mladek
2021-04-08 1:14 ` Stephen Boyd
2021-04-08 6:20 ` Stephen Boyd
2021-04-08 10:13 ` Petr Mladek
2021-04-08 19:52 ` Stephen Boyd
2021-04-08 21:08 ` Stephen Boyd
2021-04-09 9:19 ` Petr Mladek
2021-03-31 3:05 ` [PATCH v3 04/12] module: Add printk format to add module build ID to stacktraces Stephen Boyd
2021-04-07 14:54 ` Petr Mladek
2021-04-07 15:07 ` Andy Shevchenko
2021-04-07 15:03 ` Petr Mladek
2021-04-07 15:37 ` Andy Shevchenko
2021-04-08 6:58 ` Stephen Boyd
2021-04-08 13:44 ` Jessica Yu
2021-04-08 14:05 ` Andy Shevchenko
2021-04-08 19:57 ` Stephen Boyd [this message]
2021-03-31 3:05 ` [PATCH v3 05/12] arm64: stacktrace: Use %pSb for backtrace printing Stephen Boyd
2021-03-31 3:05 ` [PATCH v3 06/12] x86/dumpstack: " Stephen Boyd
2021-03-31 3:05 ` [PATCH v3 07/12] scripts/decode_stacktrace.sh: Support debuginfod Stephen Boyd
2021-03-31 3:05 ` [PATCH v3 08/12] scripts/decode_stacktrace.sh: Silence stderr messages from addr2line/nm Stephen Boyd
2021-03-31 3:05 ` [PATCH v3 09/12] scripts/decode_stacktrace.sh: Indicate 'auto' can be used for base path Stephen Boyd
2021-03-31 3:05 ` [PATCH v3 10/12] buildid: Mark some arguments const Stephen Boyd
2021-03-31 3:05 ` [PATCH v3 11/12] buildid: Fix kernel-doc notation Stephen Boyd
2021-03-31 3:05 ` [PATCH v3 12/12] kdump: Use vmlinux_build_id to simplify Stephen Boyd
2021-04-07 17:03 ` Petr Mladek
2021-04-08 5:36 ` Stephen Boyd
2021-04-08 10:17 ` Baoquan He
2021-04-08 19:58 ` Stephen Boyd
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