From: Stephen Boyd <swboyd@chromium.org>
To: Petr Mladek <pmladek@suse.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org, Jiri Olsa <jolsa@kernel.org>,
Alexei Starovoitov <ast@kernel.org>, Jessica Yu <jeyu@kernel.org>,
Evan Green <evgreen@chromium.org>,
Hsin-Yi Wang <hsinyi@chromium.org>,
Steven Rostedt <rostedt@goodmis.org>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
Matthew Wilcox <willy@infradead.org>
Subject: Re: [PATCH v4 04/13] dump_stack: Add vmlinux build ID to stack traces
Date: Tue, 13 Apr 2021 13:36:48 -0700 [thread overview]
Message-ID: <161834620810.3764895.16783352875023260799@swboyd.mtv.corp.google.com> (raw)
In-Reply-To: <YHWthzF+l0iacMuw@alley>
Quoting Petr Mladek (2021-04-13 07:41:11)
> > diff --git a/lib/dump_stack.c b/lib/dump_stack.c
> > index f5a33b6f773f..d685331b065f 100644
> > --- a/lib/dump_stack.c
> > +++ b/lib/dump_stack.c
> > @@ -5,6 +5,7 @@
> > */
> >
> > #include <linux/kernel.h>
> > +#include <linux/buildid.h>
> > #include <linux/export.h>
> > #include <linux/sched.h>
> > #include <linux/sched/debug.h>
> > @@ -36,6 +37,14 @@ void __init dump_stack_set_arch_desc(const char *fmt, ...)
> > va_end(args);
> > }
> >
> > +#if IS_ENABLED(CONFIG_STACKTRACE_BUILD_ID)
> > +#define BUILD_ID_FMT " %20phN"
> > +#define BUILD_ID_VAL vmlinux_build_id
> > +#else
> > +#define BUILD_ID_FMT "%s"
> > +#define BUILD_ID_VAL ""
> > +#endif
>
> 3rd patch always defines and initializes vmlinux_build_id. But it is
> used only when CONFIG_STACKTRACE_BUILD_ID is enabled.
It is also used for crash code.
> Is it intentional, please?
Yes, mostly for simplicity with the other user.
>
> It is not a big deal for vmlinux_build_id. But it is more questionable
> for the per-module id. I am going to open this question for 5th patch
> as well.
>
Right, for the vmlinux_build_id symbol it is not exported, and the whole
buildid.c file is part of lib-y, so if the symbol isn't used the linker
should drop it during link phase. I can drop the early init call if the
config is disabled and crash kernel code isn't enabled, and then rely on
the linker to drop the vmlinux_build_id symbol. Let me see if that can
work so that we don't have to parse it at boot if it is never used.
next prev parent reply other threads:[~2021-04-13 20:36 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-10 1:52 [PATCH v4 00/13] Add build ID to stacktraces Stephen Boyd
2021-04-10 1:52 ` [PATCH v4 01/13] buildid: Only consider GNU notes for build ID parsing Stephen Boyd
2021-04-13 14:34 ` Petr Mladek
2021-04-10 1:52 ` [PATCH v4 02/13] buildid: Add API to parse build ID out of buffer Stephen Boyd
2021-04-10 1:52 ` [PATCH v4 03/13] buildid: Stash away kernels build ID on init Stephen Boyd
2021-04-10 1:52 ` [PATCH v4 04/13] dump_stack: Add vmlinux build ID to stack traces Stephen Boyd
2021-04-13 14:41 ` Petr Mladek
2021-04-13 20:36 ` Stephen Boyd [this message]
2021-04-10 1:52 ` [PATCH v4 05/13] module: Add printk formats to add module build ID to stacktraces Stephen Boyd
2021-04-12 11:58 ` Andy Shevchenko
2021-04-12 19:29 ` Stephen Boyd
2021-04-13 10:56 ` Andy Shevchenko
2021-04-13 15:16 ` Petr Mladek
2021-04-13 20:10 ` Stephen Boyd
2021-04-13 22:36 ` Stephen Boyd
2021-04-13 15:01 ` Petr Mladek
2021-04-13 22:57 ` Stephen Boyd
2021-04-15 8:53 ` Petr Mladek
2021-04-15 13:04 ` Jessica Yu
2021-04-18 1:52 ` Stephen Boyd
2021-04-19 10:34 ` Jessica Yu
2021-04-10 1:52 ` [PATCH v4 06/13] arm64: stacktrace: Use %pSb for backtrace printing Stephen Boyd
2021-04-10 1:52 ` [PATCH v4 07/13] x86/dumpstack: Use %pSb/%pBb " Stephen Boyd
2021-04-10 1:52 ` [PATCH v4 08/13] scripts/decode_stacktrace.sh: Support debuginfod Stephen Boyd
2021-04-10 1:52 ` [PATCH v4 09/13] scripts/decode_stacktrace.sh: Silence stderr messages from addr2line/nm Stephen Boyd
2021-04-10 1:52 ` [PATCH v4 10/13] scripts/decode_stacktrace.sh: Indicate 'auto' can be used for base path Stephen Boyd
2021-04-10 1:52 ` [PATCH v4 11/13] buildid: Mark some arguments const Stephen Boyd
2021-04-10 1:52 ` [PATCH v4 12/13] buildid: Fix kernel-doc notation Stephen Boyd
2021-04-10 1:53 ` [PATCH v4 13/13] kdump: Use vmlinux_build_id to simplify Stephen Boyd
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