xref: /linux/scripts/decode_stacktrace.sh (revision 4e0ae876f77bc01a7e77724dea57b4b82bd53244)
1#!/bin/bash
2# SPDX-License-Identifier: GPL-2.0
3# (c) 2014, Sasha Levin <sasha.levin@oracle.com>
4#set -x
5
6if [[ $# < 2 ]]; then
7	echo "Usage:"
8	echo "	$0 [vmlinux] [base path] [modules path]"
9	exit 1
10fi
11
12vmlinux=$1
13basepath=$2
14modpath=$3
15declare -A cache
16declare -A modcache
17
18parse_symbol() {
19	# The structure of symbol at this point is:
20	#   ([name]+[offset]/[total length])
21	#
22	# For example:
23	#   do_basic_setup+0x9c/0xbf
24
25	if [[ $module == "" ]] ; then
26		local objfile=$vmlinux
27	elif [[ "${modcache[$module]+isset}" == "isset" ]]; then
28		local objfile=${modcache[$module]}
29	else
30		[[ $modpath == "" ]] && return
31		local objfile=$(find "$modpath" -name $module.ko -print -quit)
32		[[ $objfile == "" ]] && return
33		modcache[$module]=$objfile
34	fi
35
36	# Remove the englobing parenthesis
37	symbol=${symbol#\(}
38	symbol=${symbol%\)}
39
40	# Strip segment
41	local segment
42	if [[ $symbol == *:* ]] ; then
43		segment=${symbol%%:*}:
44		symbol=${symbol#*:}
45	fi
46
47	# Strip the symbol name so that we could look it up
48	local name=${symbol%+*}
49
50	# Use 'nm vmlinux' to figure out the base address of said symbol.
51	# It's actually faster to call it every time than to load it
52	# all into bash.
53	if [[ "${cache[$module,$name]+isset}" == "isset" ]]; then
54		local base_addr=${cache[$module,$name]}
55	else
56		local base_addr=$(nm "$objfile" | grep -i ' t ' | awk "/ $name\$/ {print \$1}" | head -n1)
57		cache[$module,$name]="$base_addr"
58	fi
59	# Let's start doing the math to get the exact address into the
60	# symbol. First, strip out the symbol total length.
61	local expr=${symbol%/*}
62
63	# Now, replace the symbol name with the base address we found
64	# before.
65	expr=${expr/$name/0x$base_addr}
66
67	# Evaluate it to find the actual address
68	expr=$((expr))
69	local address=$(printf "%x\n" "$expr")
70
71	# Pass it to addr2line to get filename and line number
72	# Could get more than one result
73	if [[ "${cache[$module,$address]+isset}" == "isset" ]]; then
74		local code=${cache[$module,$address]}
75	else
76		local code=$(addr2line -i -e "$objfile" "$address")
77		cache[$module,$address]=$code
78	fi
79
80	# addr2line doesn't return a proper error code if it fails, so
81	# we detect it using the value it prints so that we could preserve
82	# the offset/size into the function and bail out
83	if [[ $code == "??:0" ]]; then
84		return
85	fi
86
87	# Strip out the base of the path
88	code=${code//^$basepath/""}
89
90	# In the case of inlines, move everything to same line
91	code=${code//$'\n'/' '}
92
93	# Replace old address with pretty line numbers
94	symbol="$segment$name ($code)"
95}
96
97decode_code() {
98	local scripts=`dirname "${BASH_SOURCE[0]}"`
99
100	echo "$1" | $scripts/decodecode
101}
102
103handle_line() {
104	local words
105
106	# Tokenize
107	read -a words <<<"$1"
108
109	# Remove hex numbers. Do it ourselves until it happens in the
110	# kernel
111
112	# We need to know the index of the last element before we
113	# remove elements because arrays are sparse
114	local last=$(( ${#words[@]} - 1 ))
115
116	for i in "${!words[@]}"; do
117		# Remove the address
118		if [[ ${words[$i]} =~ \[\<([^]]+)\>\] ]]; then
119			unset words[$i]
120		fi
121
122		# Format timestamps with tabs
123		if [[ ${words[$i]} == \[ && ${words[$i+1]} == *\] ]]; then
124			unset words[$i]
125			words[$i+1]=$(printf "[%13s\n" "${words[$i+1]}")
126		fi
127	done
128
129	if [[ ${words[$last]} =~ \[([^]]+)\] ]]; then
130		module=${words[$last]}
131		module=${module#\[}
132		module=${module%\]}
133		symbol=${words[$last-1]}
134		unset words[$last-1]
135	else
136		# The symbol is the last element, process it
137		symbol=${words[$last]}
138		module=
139	fi
140
141	unset words[$last]
142	parse_symbol # modifies $symbol
143
144	# Add up the line number to the symbol
145	echo "${words[@]}" "$symbol $module"
146}
147
148while read line; do
149	# Let's see if we have an address in the line
150	if [[ $line =~ \[\<([^]]+)\>\] ]] ||
151	   [[ $line =~ [^+\ ]+\+0x[0-9a-f]+/0x[0-9a-f]+ ]]; then
152		# Translate address to line numbers
153		handle_line "$line"
154	# Is it a code line?
155	elif [[ $line == *Code:* ]]; then
156		decode_code "$line"
157	else
158		# Nothing special in this line, show it as is
159		echo "$line"
160	fi
161done
162