From: Sean Christopherson <seanjc@google.com>
To: Borislav Petkov <bp@alien8.de>
Cc: Jonathan Corbet <corbet@lwn.net>, x86-ml <x86@kernel.org>,
lkml <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] Documentation/submitting-patches: Add blurb about backtraces in commit messages
Date: Tue, 22 Dec 2020 10:59:22 -0800 [thread overview]
Message-ID: <X+JCCqTJkgZASj7T@google.com> (raw)
In-Reply-To: <20201222130555.GA13463@zn.tnic>
On Tue, Dec 22, 2020, Borislav Petkov wrote:
> Ok, here's the next one which I think, is also, not really controversial.
Heh, are you trying to jinx yourself?
> diff --git a/Documentation/process/submitting-patches.rst b/Documentation/process/submitting-patches.rst
> index 5ba54120bef7..0ffb21366381 100644
> --- a/Documentation/process/submitting-patches.rst
> +++ b/Documentation/process/submitting-patches.rst
> @@ -679,6 +679,26 @@ generates appropriate diffstats by default.)
> See more details on the proper patch format in the following
> references.
>
> +Backtraces in commit mesages
> +^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> +
> +Backtraces help document the call chain leading to a problem. However,
> +not all backtraces are helpful. For example, early boot call chains are
> +unique and obvious.
I'd argue that there is still value in the backtrace though, e.g. I find them
very helpful when doing git archaeology. A backtrace is an easily recognizable
signature (don't have to read a bunch of text to understand there was a splat of
some kind), and the call stack is often helpful even if it is unique, e.g. for
unfamiliar code (including early boot chains) and/or code that is substantially
different from the current upstream.
> Copying the full dmesg output verbatim, however,
> +adds distracting information like timestamps, module lists, register and
> +stack dumps.
> +
> +Therefore, the most useful backtraces should distill the relevant
> +information from the dump, which makes it easier to focus on the real
> +issue. Here is an example of a well-trimmed backtrace::
> +
> + unchecked MSR access error: WRMSR to 0xd51 (tried to write 0x0000000000000064)
> + at rIP: 0xffffffffae059994 (native_write_msr+0x4/0x20)
> + Call Trace:
> + mba_wrmsr
> + update_domains
> + rdtgroup_mkdir
> +
> .. _explicit_in_reply_to:
I'd prefer not to encourage people to strip the info after the function name,
though I do agree it's somewhat distracting (especially the offset/size). The
module, call site in the function, exact file/line if available, etc... provides
context that I find helpful for building a mental model of what went wrong.
E.g. which modules are in play, which short wrapper functions can likely be
glossed over, etc...
next prev parent reply other threads:[~2020-12-22 19:00 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-17 18:37 [PATCH] Documentation/submitting-patches: Document the SoB chain Borislav Petkov
2020-12-21 16:54 ` Jonathan Corbet
2020-12-22 13:05 ` [PATCH] Documentation/submitting-patches: Add blurb about backtraces in commit messages Borislav Petkov
2020-12-22 18:59 ` Sean Christopherson [this message]
2020-12-22 19:25 ` Borislav Petkov
2020-12-28 17:59 ` Sean Christopherson
2020-12-28 18:15 ` Borislav Petkov
2020-12-28 19:02 ` Sean Christopherson
2021-01-04 23:19 ` Jonathan Corbet
2021-01-05 10:48 ` Borislav Petkov
2021-02-02 15:43 ` Borislav Petkov
2021-02-04 21:20 ` Jonathan Corbet
2021-02-15 14:19 ` [PATCH] Documentation/submitting-patches: Extend commit message layout description Borislav Petkov
2021-02-25 11:40 ` Robert Richter
2021-03-01 22:10 ` Jonathan Corbet
2021-04-13 11:38 ` [PATCH] Documentation/submitting-patches: Document RESEND tag on patches Borislav Petkov
2021-04-13 21:02 ` Jonathan Corbet
2021-04-15 6:05 ` Borislav Petkov
2021-05-31 14:35 ` Borislav Petkov
2021-06-01 22:27 ` Jonathan Corbet
2021-06-01 22:31 ` Randy Dunlap
2021-06-01 22:37 ` Borislav Petkov
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