linux-kernel - Re: [PATCH] scripts/decode_stacktrace.sh: better support to ARM32 module stack trace

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Date: Wed, 22 May 2024 12:10:25 +0800
From: xndcn <xndchn@...il.com>
To: Elliot Berman <quic_eberman@...cinc.com>
Cc: akpm@...ux-foundation.org, linux-kernel@...r.kernel.org, 
	quic_bjorande@...cinc.com, cmllamas@...gle.com
Subject: Re: [PATCH] scripts/decode_stacktrace.sh: better support to ARM32
 module stack trace

Thanks, I'll split it into 2 patches later.

> Your change is to strip any leading/trailing characters before/after the [ / ] respectively?
Yes, exactly.

> Isn't this a problem for $symbol as well
there is already a strip logic in "parse_symbol()", which seems
introduced by #e260fe01, also for ARM.
> # Remove the englobing parenthesis
> symbol=${symbol#\(}
> symbol=${symbol%\)}

On Wed, May 22, 2024 at 10:48 AM Elliot Berman <quic_eberman@...cinc.com> wrote:
>
> On Wed, May 22, 2024 at 09:05:59AM +0800, Xiong Nandi wrote:
> > Sorry about the name, it is some kind of abbreviation. So I re-post here:
> > ---
> > Since System.map is generated by cross-compile nm tool, we should use it
> > here too. Otherwise host nm may not recognize thumb2 function address well.
> >
> > Beside, sometimes special characters around module name, such as ARM32
> > with BACKTRACE_VERBOSE in "(%pS)" format, such as:
> > [<806e4845>] (dump_stack_lvl) from [<7f806013>] (hello_init+0x13/0x1000 [test])
> >
> > After stripping other characters around "[module]", it can be finally decoded:
> > (dump_stack_lvl) from hello_init (/foo/test.c:10) test
> >
> > Signed-off-by: Xiong Nandi <xndchn@...il.com>
> > ---
> >  scripts/decode_stacktrace.sh | 7 ++++---
> >  1 file changed, 4 insertions(+), 3 deletions(-)
> >
> > diff --git a/scripts/decode_stacktrace.sh b/scripts/decode_stacktrace.sh
> > index fa5be6f57b00..324e4a6c260a 100755
> > --- a/scripts/decode_stacktrace.sh
> > +++ b/scripts/decode_stacktrace.sh
> > @@ -30,6 +30,7 @@ fi
> >
> >  READELF=${UTIL_PREFIX}readelf${UTIL_SUFFIX}
> >  ADDR2LINE=${UTIL_PREFIX}addr2line${UTIL_SUFFIX}
> > +NM=${UTIL_PREFIX}nm${UTIL_SUFFIX}
> >
> >  if [[ $1 == "-r" ]] ; then
> >       vmlinux=""
> > @@ -158,7 +159,7 @@ parse_symbol() {
> >       if [[ $aarray_support == true && "${cache[$module,$name]+isset}" == "isset" ]]; then
> >               local base_addr=${cache[$module,$name]}
> >       else
> > -             local base_addr=$(nm "$objfile" 2>/dev/null | awk '$3 == "'$name'" && ($2 == "t" || $2 == "T") {print $1; exit}')
> > +             local base_addr=$(${NM} "$objfile" 2>/dev/null | awk '$3 == "'$name'" && ($2 == "t" || $2 == "T") {print $1; exit}')
>
> The nm parts should be a separate patch.
>
> >               if [[ $base_addr == "" ]] ; then
> >                       # address not found
> >                       return
> > @@ -282,8 +283,8 @@ handle_line() {
> >
> >       if [[ ${words[$last]} =~ \[([^]]+)\] ]]; then
> >               module=${words[$last]}
> > -             module=${module#\[}
> > -             module=${module%\]}
> > +             module=${module#*\[}
> > +             module=${module%\]*}
>
> I need to get a moment to play with it. Is my understanding correct that
> the problem is that the last word ($module) is:
>
> [test])
>
> and after the existing strip logic, $module becomes test]) whereas
> expecting just "test"? Your change is to strip any leading/trailing
> characters before/after the [ / ] respectively? Isn't this a problem for
> $symbol as well -- it would be "(hello_init+0x13/0x1000" in the example.
>
> - Elliot
>
> >               modbuildid=${module#* }
> >               module=${module% *}
> >               if [[ $modbuildid == $module ]]; then
> > --
> > 2.25.1
> >