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Subject: Re: [PATCH 5/7] printk: Make %pS and friends print module build ID
From:   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>,
        Petr Mladek <pmladek@suse.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        linux-doc@vger.kernel.org
To:     Matthew Wilcox <willy@infradead.org>,
        Rasmus Villemoes <linux@rasmusvillemoes.dk>
Date:   Thu, 04 Mar 2021 20:21:18 -0800
Message-ID: <161491807864.1478170.14069558494579871831@swboyd.mtv.corp.google.com>
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Quoting Rasmus Villemoes (2021-03-04 15:11:47)
> On 04/03/2021 20.15, Stephen Boyd wrote:
> > Quoting Matthew Wilcox (2021-03-04 09:00:52)
> >> On Mon, Mar 01, 2021 at 09:47:47AM -0800, Stephen Boyd wrote:
> >>> Example:
> >>>
> >>>  WARNING: CPU: 4 PID: 3255 at drivers/misc/lkdtm/bugs.c:83 lkdtm_WARN=
ING+0x28/0x30 [lkdtm] (ed5019fdf5e53be37cb1ba7899292d7e143b259e)
> >>
> >> Would the first 12 characters instead of all 40 make it more palatable
> >> without reducing its utility?
> >=20
> > I can't seem to request debuginfo from debuginfod without the full 40
> > characters. It's not a git sha1 hash.=20
> >=20
> >> And I feel it should be within the [], so maybe this:
> >>
> >> WARNING: CPU: 4 PID: 3255 at drivers/misc/lkdtm/bugs.c:83 lkdtm_WARNIN=
G+0x28/0x30 [lkdtm ed5019fdf5e5]
> >>
> >=20
> > Sure I could put the hex numbers inside the brackets. I suspect changing
> > %pS or updating the "Modules linked in:" line isn't going to be
> > palatable. I've decided to introduce another printk format %pT to print
> > the stacktrace=20
>=20
> Can you avoid claiming a new "top-level" %p modifier? Isn't it better to
> add a new flag to '%pS', say '%pSb' to include build-id?
>=20

I see that %pSR is used in alpha for the stacktrace. I guess we can have
%pSb and %pSr then.