* [PATCH v6 06/13] arm64: stacktrace: Use %pSb for backtrace printing
2021-05-11 0:38 [PATCH v6 00/13] Add build ID to stacktraces Stephen Boyd
@ 2021-05-11 0:38 ` Stephen Boyd
2021-05-11 11:48 ` [PATCH v6 00/13] Add build ID to stacktraces Petr Mladek
2021-05-11 12:36 ` David Laight
2 siblings, 0 replies; 9+ messages in thread
From: Stephen Boyd @ 2021-05-11 0:38 UTC (permalink / raw)
To: Andrew Morton, Petr Mladek
Cc: linux-kernel, Catalin Marinas, Will Deacon, linux-arm-kernel,
Jiri Olsa, Alexei Starovoitov, Jessica Yu, Evan Green,
Hsin-Yi Wang, Steven Rostedt, Andy Shevchenko, Matthew Wilcox
Let's use the new printk format to print the stacktrace entry when
printing a backtrace to the kernel logs. This will include any module's
build ID[1] in it so that offline/crash debugging can easily locate the
debuginfo for a module via something like debuginfod[2].
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: <linux-arm-kernel@lists.infradead.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Jessica Yu <jeyu@kernel.org>
Cc: Evan Green <evgreen@chromium.org>
Cc: Hsin-Yi Wang <hsinyi@chromium.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Link: https://fedoraproject.org/wiki/Releases/FeatureBuildId [1]
Link: https://sourceware.org/elfutils/Debuginfod.html [2]
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
---
arch/arm64/kernel/stacktrace.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c
index d55bdfb7789c..ddb64ada74c2 100644
--- a/arch/arm64/kernel/stacktrace.c
+++ b/arch/arm64/kernel/stacktrace.c
@@ -129,7 +129,7 @@ NOKPROBE_SYMBOL(walk_stackframe);
static void dump_backtrace_entry(unsigned long where, const char *loglvl)
{
- printk("%s %pS\n", loglvl, (void *)where);
+ printk("%s %pSb\n", loglvl, (void *)where);
}
void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk,
--
https://chromeos.dev
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^ permalink raw reply related [flat|nested] 9+ messages in thread
* Re: [PATCH v6 00/13] Add build ID to stacktraces
2021-05-11 0:38 [PATCH v6 00/13] Add build ID to stacktraces Stephen Boyd
2021-05-11 0:38 ` [PATCH v6 06/13] arm64: stacktrace: Use %pSb for backtrace printing Stephen Boyd
@ 2021-05-11 11:48 ` Petr Mladek
2021-05-11 12:36 ` David Laight
2 siblings, 0 replies; 9+ messages in thread
From: Petr Mladek @ 2021-05-11 11:48 UTC (permalink / raw)
To: Stephen Boyd
Cc: Andrew Morton, linux-kernel, Alexei Starovoitov, Andy Shevchenko,
Baoquan He, Borislav Petkov, Catalin Marinas, Dave Young,
Evan Green, Hsin-Yi Wang, Ingo Molnar, Jessica Yu, Jiri Olsa,
kexec, Konstantin Khlebnikov, linux-arm-kernel, linux-doc,
Matthew Wilcox, Rasmus Villemoes, Sasha Levin,
Sergey Senozhatsky, Steven Rostedt, Thomas Gleixner, Vivek Goyal,
Will Deacon, x86, Christoph Hellwig, peter enderborg
On Mon 2021-05-10 17:38:32, Stephen Boyd wrote:
> This series adds the kernel's build ID[1] to the stacktrace header
> printed in oops messages, warnings, etc. and the build ID for any module
> that appears in the stacktrace after the module name. The goal is to
> make the stacktrace more self-contained and descriptive by including the
> relevant build IDs in the kernel logs when something goes wrong. This
> can be used by post processing tools like script/decode_stacktrace.sh
> and kernel developers to easily locate the debug info associated with a
> kernel crash and line up what line and file things started falling apart
> at.
The entire series looks good to me.
I reviewed carefully only the 5th patch touching printk/kallsyms/module
code. I just scanned over the other patches touching kernel code
and did not notice any obvious problem. I did not check the changes
in decode_stacktrace.sh at all.
I tried to get stacktraces on x86_64 and it worked as expected.
Best Regards,
Petr
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^ permalink raw reply [flat|nested] 9+ messages in thread
* RE: [PATCH v6 00/13] Add build ID to stacktraces
2021-05-11 0:38 [PATCH v6 00/13] Add build ID to stacktraces Stephen Boyd
2021-05-11 0:38 ` [PATCH v6 06/13] arm64: stacktrace: Use %pSb for backtrace printing Stephen Boyd
2021-05-11 11:48 ` [PATCH v6 00/13] Add build ID to stacktraces Petr Mladek
@ 2021-05-11 12:36 ` David Laight
2021-05-11 12:52 ` Steven Rostedt
2 siblings, 1 reply; 9+ messages in thread
From: David Laight @ 2021-05-11 12:36 UTC (permalink / raw)
To: 'Stephen Boyd', Andrew Morton, Petr Mladek
Cc: linux-kernel, Alexei Starovoitov, Andy Shevchenko, Baoquan He,
Borislav Petkov, Catalin Marinas, Dave Young, Evan Green,
Hsin-Yi Wang, Ingo Molnar, Jessica Yu, Jiri Olsa, kexec,
Konstantin Khlebnikov, linux-arm-kernel, linux-doc,
Matthew Wilcox, Rasmus Villemoes, Sasha Levin,
Sergey Senozhatsky, Steven Rostedt, Thomas Gleixner, Vivek Goyal,
Will Deacon, x86, Christoph Hellwig, peter enderborg
From: Stephen Boyd
> Sent: 11 May 2021 01:39
>
> This series adds the kernel's build ID[1] to the stacktrace header
> printed in oops messages, warnings, etc. and the build ID for any module
> that appears in the stacktrace after the module name. The goal is to
> make the stacktrace more self-contained and descriptive by including the
> relevant build IDs in the kernel logs when something goes wrong. This
> can be used by post processing tools like script/decode_stacktrace.sh
> and kernel developers to easily locate the debug info associated with a
> kernel crash and line up what line and file things started falling apart
> at.
>
> To show how this can be used I've included a patch to
> decode_stacktrace.sh that downloads the debuginfo from a debuginfod
> server.
...
> Here's an example lkdtm stacktrace on arm64.
>
> 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)
...
> 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?
David
-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
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^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH v6 00/13] Add build ID to stacktraces
2021-05-11 12:36 ` David Laight
@ 2021-05-11 12:52 ` Steven Rostedt
2021-05-11 12:58 ` David Laight
0 siblings, 1 reply; 9+ messages in thread
From: Steven Rostedt @ 2021-05-11 12:52 UTC (permalink / raw)
To: David Laight
Cc: 'Stephen Boyd',
Andrew Morton, Petr Mladek, linux-kernel, Alexei Starovoitov,
Andy Shevchenko, Baoquan He, Borislav Petkov, Catalin Marinas,
Dave Young, Evan Green, Hsin-Yi Wang, Ingo Molnar, Jessica Yu,
Jiri Olsa, kexec, Konstantin Khlebnikov, linux-arm-kernel,
linux-doc, Matthew Wilcox, Rasmus Villemoes, Sasha Levin,
Sergey Senozhatsky, Thomas Gleixner, Vivek Goyal, Will Deacon,
x86, Christoph Hellwig, peter enderborg
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.
-- Steve
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^ permalink raw reply [flat|nested] 9+ messages in thread
* RE: [PATCH v6 00/13] Add build ID to stacktraces
2021-05-11 12:52 ` Steven Rostedt
@ 2021-05-11 12:58 ` David Laight
2021-05-11 14:21 ` Petr Mladek
0 siblings, 1 reply; 9+ messages in thread
From: David Laight @ 2021-05-11 12:58 UTC (permalink / raw)
To: 'Steven Rostedt'
Cc: 'Stephen Boyd',
Andrew Morton, Petr Mladek, linux-kernel, Alexei Starovoitov,
Andy Shevchenko, Baoquan He, Borislav Petkov, Catalin Marinas,
Dave Young, Evan Green, Hsin-Yi Wang, Ingo Molnar, Jessica Yu,
Jiri Olsa, kexec, Konstantin Khlebnikov, linux-arm-kernel,
linux-doc, Matthew Wilcox, Rasmus Villemoes, Sasha Levin,
Sergey Senozhatsky, Thomas Gleixner, Vivek Goyal, Will Deacon,
x86, Christoph Hellwig, peter enderborg
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 :-)
David
-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
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^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH v6 00/13] Add build ID to stacktraces
2021-05-11 12:58 ` David Laight
@ 2021-05-11 14:21 ` Petr Mladek
2021-05-11 14:31 ` David Laight
0 siblings, 1 reply; 9+ messages in thread
From: Petr Mladek @ 2021-05-11 14:21 UTC (permalink / raw)
To: David Laight
Cc: 'Steven Rostedt', 'Stephen Boyd',
Andrew Morton, linux-kernel, Alexei Starovoitov, Andy Shevchenko,
Baoquan He, Borislav Petkov, Catalin Marinas, Dave Young,
Evan Green, Hsin-Yi Wang, Ingo Molnar, Jessica Yu, Jiri Olsa,
kexec, Konstantin Khlebnikov, linux-arm-kernel, linux-doc,
Matthew Wilcox, Rasmus Villemoes, Sasha Levin,
Sergey Senozhatsky, Thomas Gleixner, Vivek Goyal, Will Deacon,
x86, Christoph Hellwig, peter enderborg
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.
Best Regards,
Petr
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^ permalink raw reply [flat|nested] 9+ messages in thread
* RE: [PATCH v6 00/13] Add build ID to stacktraces
2021-05-11 14:21 ` Petr Mladek
@ 2021-05-11 14:31 ` David Laight
2021-05-11 14:35 ` Matthew Wilcox
0 siblings, 1 reply; 9+ messages in thread
From: David Laight @ 2021-05-11 14:31 UTC (permalink / raw)
To: 'Petr Mladek'
Cc: 'Steven Rostedt', 'Stephen Boyd',
Andrew Morton, linux-kernel, Alexei Starovoitov, Andy Shevchenko,
Baoquan He, Borislav Petkov, Catalin Marinas, Dave Young,
Evan Green, Hsin-Yi Wang, Ingo Molnar, Jessica Yu, Jiri Olsa,
kexec, Konstantin Khlebnikov, linux-arm-kernel, linux-doc,
Matthew Wilcox, Rasmus Villemoes, Sasha Levin,
Sergey Senozhatsky, Thomas Gleixner, Vivek Goyal, Will Deacon,
x86, Christoph Hellwig, peter enderborg
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
-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
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^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH v6 00/13] Add build ID to stacktraces
2021-05-11 14:31 ` David Laight
@ 2021-05-11 14:35 ` Matthew Wilcox
0 siblings, 0 replies; 9+ messages in thread
From: Matthew Wilcox @ 2021-05-11 14:35 UTC (permalink / raw)
To: David Laight
Cc: 'Petr Mladek', 'Steven Rostedt',
'Stephen Boyd',
Andrew Morton, linux-kernel, Alexei Starovoitov, Andy Shevchenko,
Baoquan He, Borislav Petkov, Catalin Marinas, Dave Young,
Evan Green, Hsin-Yi Wang, Ingo Molnar, Jessica Yu, Jiri Olsa,
kexec, Konstantin Khlebnikov, linux-arm-kernel, linux-doc,
Rasmus Villemoes, Sasha Levin, Sergey Senozhatsky,
Thomas Gleixner, Vivek Goyal, Will Deacon, x86,
Christoph Hellwig, peter enderborg
On Tue, May 11, 2021 at 02:31:38PM +0000, David Laight wrote:
> 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.
asked and answered. please review the bidding.
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