This small series improves usability of scripts/decode_stacktrace.sh by
improving the usage text and correctly reporting when modules are built
without debugging symbols.
Signed-off-by: Luca Ceresoli <[email protected]>
---
Luca Ceresoli (3):
scripts/decode_stacktrace.sh: remove find_module recursion and improve error reporting
scripts/decode_stacktrace.sh: clarify command line
scripts/decode_stacktrace.sh: add '-h' flag
scripts/decode_stacktrace.sh | 49 ++++++++++++++++++++++++--------------------
1 file changed, 27 insertions(+), 22 deletions(-)
---
base-commit: e8f897f4afef0031fe618a8e94127a0934896aba
change-id: 20240311-decode_stacktrace-find_module-improvements-a02aee28fbaf
Best regards,
--
Luca Ceresoli <[email protected]>
The find_module() function can fail for two reasons:
* the module was not found
* the module was found but without debugging info
In both cases the user is reported the same error:
WARNING! Modules path isn't set, but is needed to parse this symbol
This is misleading in case the modules path is set correctly.
find_module() is currently implemented as a recursive function based on
global variables in order to check up to 4 different paths. This is not
straightforward to read and even less to modify.
Besides, the debuginfod code at the beginning of find_module() is executed
identlcally every time the function is entered, i.e. up to 4 times per each
module search due to recursion.
To be able to improve error reporting, first rewrite the find_module()
function to remove recursion. The new version of the function iterates over
all the same (up to 4) paths as before and for each of them does the same
checks as before. At the end of the iteration it is now able to print an
appropriate error message, so that has been moved from the caller into
find_module().
Finally, when the module is found but without debugging info, mention the
two Kconfig variables one needs to set in order to have the needed
debugging symbols.
Signed-off-by: Luca Ceresoli <[email protected]>
---
scripts/decode_stacktrace.sh | 40 ++++++++++++++++++++--------------------
1 file changed, 20 insertions(+), 20 deletions(-)
diff --git a/scripts/decode_stacktrace.sh b/scripts/decode_stacktrace.sh
index fa5be6f57b00..7f3fb5e82707 100755
--- a/scripts/decode_stacktrace.sh
+++ b/scripts/decode_stacktrace.sh
@@ -88,31 +88,32 @@ find_module() {
fi
fi
- if [[ "$modpath" != "" ]] ; then
- for fn in $(find "$modpath" -name "${module//_/[-_]}.ko*") ; do
- if ${READELF} -WS "$fn" | grep -qwF .debug_line ; then
- echo $fn
- return
- fi
- done
- return 1
- fi
-
- modpath=$(dirname "$vmlinux")
- find_module && return
-
- if [[ $release == "" ]] ; then
+ if [ -z $release ] ; then
release=$(gdb -ex 'print init_uts_ns.name.release' -ex 'quit' -quiet -batch "$vmlinux" 2>/dev/null | sed -n 's/\$1 = "\(.*\)".*/\1/p')
fi
+ if [ -n "${release}" ] ; then
+ release_dirs="/usr/lib/debug/lib/modules/$release /lib/modules/$release"
+ fi
- for dn in {/usr/lib/debug,}/lib/modules/$release ; do
- if [ -e "$dn" ] ; then
- modpath="$dn"
- find_module && return
+ found_without_debug_info=false
+ for dir in "$modpath" "$(dirname "$vmlinux")" ${release_dirs}; do
+ if [ -n "${dir}" ] && [ -e "${dir}" ]; then
+ for fn in $(find "$dir" -name "${module//_/[-_]}.ko*") ; do
+ if ${READELF} -WS "$fn" | grep -qwF .debug_line ; then
+ echo $fn
+ return
+ fi
+ found_without_debug_info=true
+ done
fi
done
- modpath=""
+ if [[ ${found_without_debug_info} == true ]]; then
+ echo "WARNING! No debugging info in module ${module}, rebuild with DEBUG_KERNEL and DEBUG_INFO" >&2
+ else
+ echo "WARNING! Cannot find .ko for module ${module}, please pass a valid module path" >&2
+ fi
+
return 1
}
@@ -130,7 +131,6 @@ parse_symbol() {
else
local objfile=$(find_module)
if [[ $objfile == "" ]] ; then
- echo "WARNING! Modules path isn't set, but is needed to parse this symbol" >&2
return
fi
if [[ $aarray_support == true ]]; then
--
2.34.1
When no parameters are passed, the usage instructions are presented only
when debuginfod-find is not found. This makes sense because with debuginfod
none of the positional parameters are needed. However it means that users
having debuginfod-find installed will have no chance of reading the usage
text without opening the file.
Many programs have a '-h' flag to get the usage, so add such a flag.
Invoking 'scripts/decode_stacktrace.sh -h' will now show the usage text and
exit.
Signed-off-by: Luca Ceresoli <[email protected]>
---
scripts/decode_stacktrace.sh | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/scripts/decode_stacktrace.sh b/scripts/decode_stacktrace.sh
index b56e79060e9f..e8c9976062d0 100755
--- a/scripts/decode_stacktrace.sh
+++ b/scripts/decode_stacktrace.sh
@@ -7,6 +7,7 @@ usage() {
echo "Usage:"
echo " $0 -r <release>"
echo " $0 [<vmlinux> [<base_path>|auto [<modules_path>]]]"
+ echo " $0 -h"
}
# Try to find a Rust demangler
@@ -32,7 +33,10 @@ fi
READELF=${UTIL_PREFIX}readelf${UTIL_SUFFIX}
ADDR2LINE=${UTIL_PREFIX}addr2line${UTIL_SUFFIX}
-if [[ $1 == "-r" ]] ; then
+if [[ $1 == "-h" ]] ; then
+ usage
+ exit 0
+elif [[ $1 == "-r" ]] ; then
vmlinux=""
basepath="auto"
modpath=""
--
2.34.1
Hello,
On Mon, 11 Mar 2024 16:24:53 +0100
Luca Ceresoli <[email protected]> wrote:
> This small series improves usability of scripts/decode_stacktrace.sh by
> improving the usage text and correctly reporting when modules are built
> without debugging symbols.
>
> Signed-off-by: Luca Ceresoli <[email protected]>
Gently pinging about this series.
Best regards,
Luca
--
Luca Ceresoli, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
Quoting Luca Ceresoli (2024-03-11 08:24:54)
> The find_module() function can fail for two reasons:
>
> * the module was not found
> * the module was found but without debugging info
>
> In both cases the user is reported the same error:
>
> WARNING! Modules path isn't set, but is needed to parse this symbol
>
> This is misleading in case the modules path is set correctly.
>
> find_module() is currently implemented as a recursive function based on
> global variables in order to check up to 4 different paths. This is not
> straightforward to read and even less to modify.
>
> Besides, the debuginfod code at the beginning of find_module() is executed
> identlcally every time the function is entered, i.e. up to 4 times per each
s/identlcally/identically/
> module search due to recursion.
>
> To be able to improve error reporting, first rewrite the find_module()
> function to remove recursion. The new version of the function iterates over
> all the same (up to 4) paths as before and for each of them does the same
> checks as before. At the end of the iteration it is now able to print an
> appropriate error message, so that has been moved from the caller into
> find_module().
>
> Finally, when the module is found but without debugging info, mention the
> two Kconfig variables one needs to set in order to have the needed
> debugging symbols.
>
> Signed-off-by: Luca Ceresoli <[email protected]>
> ---
Reviewed-by: Stephen Boyd <[email protected]>
Quoting Luca Ceresoli (2024-03-11 08:24:56)
> When no parameters are passed, the usage instructions are presented only
> when debuginfod-find is not found. This makes sense because with debuginfod
> none of the positional parameters are needed. However it means that users
> having debuginfod-find installed will have no chance of reading the usage
> text without opening the file.
>
> Many programs have a '-h' flag to get the usage, so add such a flag.
> Invoking 'scripts/decode_stacktrace.sh -h' will now show the usage text and
> exit.
>
> Signed-off-by: Luca Ceresoli <[email protected]>
> ---
Reviewed-by: Stephen Boyd <[email protected]>
Hello Stephen,
On Wed, 8 May 2024 17:35:53 -0400
Stephen Boyd <[email protected]> wrote:
> Quoting Luca Ceresoli (2024-03-11 08:24:54)
> > The find_module() function can fail for two reasons:
> >
> > * the module was not found
> > * the module was found but without debugging info
> >
> > In both cases the user is reported the same error:
> >
> > WARNING! Modules path isn't set, but is needed to parse this symbol
> >
> > This is misleading in case the modules path is set correctly.
> >
> > find_module() is currently implemented as a recursive function based on
> > global variables in order to check up to 4 different paths. This is not
> > straightforward to read and even less to modify.
> >
> > Besides, the debuginfod code at the beginning of find_module() is executed
> > identlcally every time the function is entered, i.e. up to 4 times per each
>
> s/identlcally/identically/
Well spotted!
Thanks for reviewing, v2 on its way.
Luca
--
Luca Ceresoli, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com