[PATCH] scripts/decode_stacktrace.sh: fix decoding of lines with an additional info

[PATCH] scripts/decode_stacktrace.sh: fix decoding of lines with an additional info

[Luca Ceresoli]

Since commit bdf8eafbf7f5 ("arm64: stacktrace: report source of unwind
data") a stack trace line can contain an additional info field that was not
present before, in the form of one or more letters in parentheses. E.g.:

  [  504.517915]  led_sysfs_enable+0x54/0x80 (P)
                                             ^^^

When this is present, decode_stacktrace decodes the line incorrectly:

  [  504.517915] led_sysfs_enable+0x54/0x80 P

Extend parsing to decode it correctly:

  [  504.517915] led_sysfs_enable (drivers/leds/led-core.c:455 (discriminator 7)) (P)

The regex to match such lines assumes the info can be extended in the
future to other uppercase characters, and will need to be extended in case
other characters will be used. Using a much more generic regex might incur
in false positives, so this looked like a good tradeoff.

Fixes: bdf8eafbf7f5 ("arm64: stacktrace: report source of unwind data")
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
---
 scripts/decode_stacktrace.sh | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/scripts/decode_stacktrace.sh b/scripts/decode_stacktrace.sh
index 46fa18b80fc1bc40734fcc9c8752af591e4e2737..17abc4e7a9855b10e76acfdb92847e1671d6c2bd 100755
--- a/scripts/decode_stacktrace.sh
+++ b/scripts/decode_stacktrace.sh
@@ -286,6 +286,18 @@ handle_line() {
 		last=$(( $last - 1 ))
 	fi
 
+	# Extract info after the symbol if present. E.g.:
+	# func_name+0x54/0x80 (P)
+	#                     ^^^
+	# The regex assumes only uppercase letters will be used. To be
+	# extended if needed.
+	local info_str=""
+	if [[ ${words[$last]} =~ \([A-Z]*\) ]]; then
+		info_str=${words[$last]}
+		unset words[$last]
+		last=$(( $last - 1 ))
+	fi
+
 	if [[ ${words[$last]} =~ \[([^]]+)\] ]]; then
 		module=${words[$last]}
 		# some traces format is "(%pS)", which like "(foo+0x0/0x1 [bar])"
@@ -313,9 +325,9 @@ handle_line() {
 	# Add up the line number to the symbol
 	if [[ -z ${module} ]]
 	then
-		echo "${words[@]}" "$symbol"
+		echo "${words[@]}" "$symbol ${info_str}"
 	else
-		echo "${words[@]}" "$symbol $module"
+		echo "${words[@]}" "$symbol $module ${info_str}"
 	fi
 }
 

---
base-commit: fc033cf25e612e840e545f8d5ad2edd6ba613ed5
change-id: 20241230-decode_stacktrace-fix-info-e3f3716019be

Best regards,
-- 
Luca Ceresoli <luca.ceresoli@bootlin.com>