From: Josh Poimboeuf <jpoimboe@redhat.com>
To: Joe Perches <joe@perches.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@kernel.org>, "H . Peter Anvin" <hpa@zytor.com>,
x86@kernel.org, linux-kernel@vger.kernel.org,
Andy Lutomirski <luto@amacapital.net>,
Linus Torvalds <torvalds@linux-foundation.org>,
Steven Rostedt <rostedt@goodmis.org>,
Brian Gerst <brgerst@gmail.com>,
Kees Cook <keescook@chromium.org>,
Peter Zijlstra <peterz@infradead.org>,
Frederic Weisbecker <fweisbec@gmail.com>,
Byungchul Park <byungchul.park@lge.com>,
Nilay Vaish <nilayvaish@gmail.com>
Subject: Re: [PATCH 3/6] x86/dumpstack: make printk_stack_address() more generally useful
Date: Wed, 24 Aug 2016 14:24:45 -0500 [thread overview]
Message-ID: <20160824192445.tiftvwceupuixays@treble> (raw)
In-Reply-To: <1472065626.3746.164.camel@perches.com>
On Wed, Aug 24, 2016 at 12:07:06PM -0700, Joe Perches wrote:
> On Wed, 2016-08-24 at 13:43 -0500, Josh Poimboeuf wrote:
> > On Wed, Aug 24, 2016 at 10:28:38AM -0700, Joe Perches wrote:
> > > On Wed, 2016-08-24 at 11:50 -0500, Josh Poimboeuf wrote:
> > > > Change printk_stack_address() to be useful when called by an unwinder
> > > > outside the context of dump_trace().
> > > >
> > > > Specifically:
> > > >
> > > > - printk_stack_address()'s 'data' argument is always used as the log
> > > > level string. Make that explicit.
> []
> > > If this is true, and I'm not sure it is as I believe
> > > there are static strings emitted like EOE and IRQ,
> > > shouldn't this bubble up through the calling tree?
>
> > []
> > This function needs to keep its 'void *data' argument because it's a
> > callback for stacktrace_ops, so it has to conform to the callback
> > interface. 'data' is used for passing a pointer to an opaque data
> > structure to the callback.
> >
> > Also this is the only caller of printk_stack_address(), so there's
> > nowhere else to bubble it up to.
>
> And that shows that print_stack_address(data is not always a log level.
> ie: walk_stack uses it to print a string not a log level.
Hm, can you be more specific? As far as I can tell, here's the only
possible call path to print_trace_address() and printk_stack_address():
show_trace_log_lvl()
dump_trace() // ops is print_trace_op
print_context_stack() // ops->walk_stack
print_trace_address() // ops->address
printk_stack_address()
So 'data' is a sneaky way to pass 'log_lvl' from show_trace_log_lvl() to
print_trace_address(), without dump_trace() and print_context_stack()
knowing what it is, because they're used in other places where 'data'
means something else.
--
Josh
next prev parent reply other threads:[~2016-08-24 19:26 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-24 16:50 [PATCH 0/6] x86/dumpstack: more stack dump improvements Josh Poimboeuf
2016-08-24 16:50 ` [PATCH 1/6] perf/x86: check perf_callchain_store() error Josh Poimboeuf
2016-09-08 9:48 ` [tip:x86/asm] perf/x86: Check " tip-bot for Josh Poimboeuf
2016-08-24 16:50 ` [PATCH 2/6] oprofile/x86: add regs->ip to oprofile trace Josh Poimboeuf
2016-08-30 11:30 ` Robert Richter
2016-09-08 9:48 ` [tip:x86/asm] oprofile/x86: Add " tip-bot for Josh Poimboeuf
2016-08-24 16:50 ` [PATCH 3/6] x86/dumpstack: make printk_stack_address() more generally useful Josh Poimboeuf
2016-08-24 17:28 ` Joe Perches
2016-08-24 18:43 ` Josh Poimboeuf
2016-08-24 19:07 ` Joe Perches
2016-08-24 19:24 ` Josh Poimboeuf [this message]
2016-08-24 19:57 ` Joe Perches
2016-08-24 18:03 ` Linus Torvalds
2016-08-24 18:22 ` Peter Zijlstra
2016-08-24 18:37 ` Linus Torvalds
2016-08-24 19:37 ` Josh Poimboeuf
2016-08-25 17:49 ` Josh Poimboeuf
2016-08-25 20:41 ` Kees Cook
2016-08-25 21:07 ` Josh Poimboeuf
[not found] ` <CA+55aFy3sgA4=ZPhiDWiRMvWj9QPhUd0JBdUr1hm_6G0aSC6uw@mail.gmail.com>
2016-08-26 2:19 ` Kees Cook
2016-08-26 3:19 ` Josh Poimboeuf
2016-08-26 4:40 ` Linus Torvalds
2016-08-26 5:56 ` Josh Poimboeuf
[not found] ` <CA+55aFy8FPRiEr-4p++TGj+keTNsg781q1E1FQZ7z4+nAs0ZaQ@mail.gmail.com>
2016-08-26 13:30 ` Josh Poimboeuf
2016-08-31 16:53 ` Josh Poimboeuf
2016-08-31 17:15 ` Linus Torvalds
2016-09-01 13:09 ` Josh Poimboeuf
2016-09-01 16:30 ` Linus Torvalds
2016-09-08 9:49 ` [tip:x86/asm] x86/dumpstack: Make " tip-bot for Josh Poimboeuf
2016-08-24 16:50 ` [PATCH 4/6] x86/dumpstack: add get_stack_pointer() and get_frame_pointer() Josh Poimboeuf
2016-09-08 9:49 ` [tip:x86/asm] x86/dumpstack: Add " tip-bot for Josh Poimboeuf
2016-08-24 16:50 ` [PATCH 5/6] x86/dumpstack: remove unnecessary stack pointer arguments Josh Poimboeuf
2016-09-08 9:50 ` [tip:x86/asm] x86/dumpstack: Remove " tip-bot for Josh Poimboeuf
2016-08-24 16:50 ` [PATCH 6/6] x86/dumpstack: allow preemption in show_stack_log_lvl() and dump_trace() Josh Poimboeuf
2016-09-08 7:04 ` Ingo Molnar
2016-09-08 21:47 ` Josh Poimboeuf
2016-09-08 21:49 ` [PATCH v2] " Josh Poimboeuf
2016-09-13 18:29 ` Ingo Molnar
2016-09-13 19:38 ` Josh Poimboeuf
2016-09-14 17:39 ` [tip:x86/asm] x86/dumpstack: Allow " tip-bot for Josh Poimboeuf
2016-09-09 6:11 ` [PATCH 6/6] x86/dumpstack: allow " Ingo Molnar
2016-09-01 13:13 ` [PATCH 0/6] x86/dumpstack: more stack dump improvements Josh Poimboeuf
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20160824192445.tiftvwceupuixays@treble \
--to=jpoimboe@redhat.com \
--cc=brgerst@gmail.com \
--cc=byungchul.park@lge.com \
--cc=fweisbec@gmail.com \
--cc=hpa@zytor.com \
--cc=joe@perches.com \
--cc=keescook@chromium.org \
--cc=linux-kernel@vger.kernel.org \
--cc=luto@amacapital.net \
--cc=mingo@kernel.org \
--cc=nilayvaish@gmail.com \
--cc=peterz@infradead.org \
--cc=rostedt@goodmis.org \
--cc=tglx@linutronix.de \
--cc=torvalds@linux-foundation.org \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).