From: Petr Mladek <pmladek@suse.com>
To: Stephen Boyd <swboyd@chromium.org>
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 v3 03/12] dump_stack: Add vmlinux build ID to stack traces
Date: Wed, 7 Apr 2021 15:42:38 +0200 [thread overview]
Message-ID: <YG22znIOouERDND0@alley> (raw)
In-Reply-To: <20210331030520.3816265-4-swboyd@chromium.org>
On Tue 2021-03-30 20:05:11, Stephen Boyd wrote:
> Add the running kernel's build ID[1] to the stacktrace information
> header. This makes it simpler for developers to locate the vmlinux with
> full debuginfo for a particular kernel stacktrace. Combined with
> scripts/decode_stracktrace.sh, a developer can download the correct
> vmlinux from a debuginfod[2] server and find the exact file and line
> number for the functions plus offsets in a stacktrace.
>
> This is especially useful for pstore crash debugging where the kernel
> crashes are recorded in the pstore logs and the recovery kernel is
> different or the debuginfo doesn't exist on the device due to space
> concerns (the data can be large and a security concern). The stacktrace
> can be analyzed after the crash by using the build ID to find the
> matching vmlinux and understand where in the function something went
> wrong.
>
> Example stacktrace from lkdtm:
>
> WARNING: CPU: 4 PID: 3255 at drivers/misc/lkdtm/bugs.c:83 lkdtm_WARNING+0x28/0x30 [lkdtm]
> Modules linked in: lkdtm rfcomm algif_hash algif_skcipher af_alg xt_cgroup uinput xt_MASQUERADE
> CPU: 4 PID: 3255 Comm: bash Not tainted 5.11 #3 aa23f7a1231c229de205662d5a9e0d4c580f19a1
> Hardware name: Google Lazor (rev3+) with KB Backlight (DT)
> pstate: 00400009 (nzcv daif +PAN -UAO -TCO BTYPE=--)
> pc : lkdtm_WARNING+0x28/0x30 [lkdtm]
>
> The hex string aa23f7a1231c229de205662d5a9e0d4c580f19a1 is the build ID,
> following the kernel version number. Put it all behind a config option,
> STACKTRACE_BUILD_ID, so that kernel developers can remove this
> information if they decide it is too much.
>
> diff --git a/lib/dump_stack.c b/lib/dump_stack.c
> index f5a33b6f773f..07e0214c2d4d 100644
> --- a/lib/dump_stack.c
> +++ b/lib/dump_stack.c
> @@ -45,13 +52,14 @@ void __init dump_stack_set_arch_desc(const char *fmt, ...)
> */
> void dump_stack_print_info(const char *log_lvl)
> {
> - printk("%sCPU: %d PID: %d Comm: %.20s %s%s %s %.*s\n",
> + printk("%sCPU: %d PID: %d Comm: %.20s %s%s %s %.*s" BUILD_ID_STR "\n",
> log_lvl, raw_smp_processor_id(), current->pid, current->comm,
> kexec_crash_loaded() ? "Kdump: loaded " : "",
> print_tainted(),
> init_utsname()->release,
> (int)strcspn(init_utsname()->version, " "),
> - init_utsname()->version);
> + init_utsname()->version,
> + IS_ENABLED(CONFIG_STACKTRACE_BUILD_ID) ? vmlinux_build_id : "");
I get the following warning when CONFIG_STACKTRACE_BUILD_ID is not
enabled:
CC lib/dump_stack.o
lib/dump_stack.c: In function ‘dump_stack_print_info’:
lib/dump_stack.c:62:67: warning: pointer type mismatch in conditional expression
IS_ENABLED(CONFIG_STACKTRACE_BUILD_ID) ? vmlinux_build_id : "");
^
lib/dump_stack.c:55:9: warning: format ‘%s’ expects argument of type ‘char *’, but argument 11 has type ‘void *’ [-Wformat=]
printk("%sCPU: %d PID: %d Comm: %.20s %s%s %s %.*s" BUILD_ID_STR "\n",
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
lib/dump_stack.c:43:24: note: format string is defined here
#define BUILD_ID_STR "%s"
~^
%p
and this when the options is enabled:
CC lib/dump_stack.o
lib/dump_stack.c: In function ‘dump_stack_print_info’:
lib/dump_stack.c:62:67: warning: pointer type mismatch in conditional expression
IS_ENABLED(CONFIG_STACKTRACE_BUILD_ID) ? vmlinux_build_id : "");
I think that you need to use something like:
#ifdef CONFIG_STACKTRACE_BUILD_ID
#define BUILD_ID_FTM " %20phN"
#define BUILD_ID_VAL vmlinux_build_id
#else
#define BUILD_ID_FTM "%s"
#define BUILD_ID_VAL ""
#endif
printk("%sCPU: %d PID: %d Comm: %.20s %s%s %s %.*s" BUILD_ID_FTM "\n",
log_lvl, raw_smp_processor_id(), current->pid, current->comm,
kexec_crash_loaded() ? "Kdump: loaded " : "",
print_tainted(),
init_utsname()->release,
(int)strcspn(init_utsname()->version, " "),
init_utsname()->version,
BUILD_ID_VAL);
Best Regards,
Petr
next prev parent reply other threads:[~2021-04-07 13:43 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 [this message]
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
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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