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

Since commit bdf8eaf ("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.

Link: https://lkml.kernel.org/r/20241230-decode_stacktrace-fix-info-v1-1-984910659173@bootlin.com
Fixes: bdf8eaf ("arm64: stacktrace: report source of unwind data")
Signed-off-by: Luca Ceresoli <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Mark Brown <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Miroslav Benes <[email protected]>
Cc: Puranjay Mohan <[email protected]>
Cc: Thomas Petazzoni <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

Author: lucaceresoli

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
 }