xref: /linux/scripts/decode_stacktrace.sh (revision be239684b18e1cdcafcf8c7face4a2f562c745ad)
1#!/bin/bash
2# SPDX-License-Identifier: GPL-2.0
3# (c) 2014, Sasha Levin <sasha.levin@oracle.com>
4#set -x
5
6usage() {
7	echo "Usage:"
8	echo "	$0 -r <release> | <vmlinux> [<base path>|auto] [<modules path>]"
9}
10
11# Try to find a Rust demangler
12if type llvm-cxxfilt >/dev/null 2>&1 ; then
13	cppfilt=llvm-cxxfilt
14elif type c++filt >/dev/null 2>&1 ; then
15	cppfilt=c++filt
16	cppfilt_opts=-i
17fi
18
19UTIL_SUFFIX=
20if [[ -z ${LLVM:-} ]]; then
21	UTIL_PREFIX=${CROSS_COMPILE:-}
22else
23	UTIL_PREFIX=llvm-
24	if [[ ${LLVM} == */ ]]; then
25		UTIL_PREFIX=${LLVM}${UTIL_PREFIX}
26	elif [[ ${LLVM} == -* ]]; then
27		UTIL_SUFFIX=${LLVM}
28	fi
29fi
30
31READELF=${UTIL_PREFIX}readelf${UTIL_SUFFIX}
32ADDR2LINE=${UTIL_PREFIX}addr2line${UTIL_SUFFIX}
33
34if [[ $1 == "-r" ]] ; then
35	vmlinux=""
36	basepath="auto"
37	modpath=""
38	release=$2
39
40	for fn in {,/usr/lib/debug}/boot/vmlinux-$release{,.debug} /lib/modules/$release{,/build}/vmlinux ; do
41		if [ -e "$fn" ] ; then
42			vmlinux=$fn
43			break
44		fi
45	done
46
47	if [[ $vmlinux == "" ]] ; then
48		echo "ERROR! vmlinux image for release $release is not found" >&2
49		usage
50		exit 2
51	fi
52else
53	vmlinux=$1
54	basepath=${2-auto}
55	modpath=$3
56	release=""
57	debuginfod=
58
59	# Can we use debuginfod-find?
60	if type debuginfod-find >/dev/null 2>&1 ; then
61		debuginfod=${1-only}
62	fi
63
64	if [[ $vmlinux == "" && -z $debuginfod ]] ; then
65		echo "ERROR! vmlinux image must be specified" >&2
66		usage
67		exit 1
68	fi
69fi
70
71declare aarray_support=true
72declare -A cache 2>/dev/null
73if [[ $? != 0 ]]; then
74	aarray_support=false
75else
76	declare -A modcache
77fi
78
79find_module() {
80	if [[ -n $debuginfod ]] ; then
81		if [[ -n $modbuildid ]] ; then
82			debuginfod-find debuginfo $modbuildid && return
83		fi
84
85		# Only using debuginfod so don't try to find vmlinux module path
86		if [[ $debuginfod == "only" ]] ; then
87			return
88		fi
89	fi
90
91	if [[ "$modpath" != "" ]] ; then
92		for fn in $(find "$modpath" -name "${module//_/[-_]}.ko*") ; do
93			if ${READELF} -WS "$fn" | grep -qwF .debug_line ; then
94				echo $fn
95				return
96			fi
97		done
98		return 1
99	fi
100
101	modpath=$(dirname "$vmlinux")
102	find_module && return
103
104	if [[ $release == "" ]] ; then
105		release=$(gdb -ex 'print init_uts_ns.name.release' -ex 'quit' -quiet -batch "$vmlinux" 2>/dev/null | sed -n 's/\$1 = "\(.*\)".*/\1/p')
106	fi
107
108	for dn in {/usr/lib/debug,}/lib/modules/$release ; do
109		if [ -e "$dn" ] ; then
110			modpath="$dn"
111			find_module && return
112		fi
113	done
114
115	modpath=""
116	return 1
117}
118
119parse_symbol() {
120	# The structure of symbol at this point is:
121	#   ([name]+[offset]/[total length])
122	#
123	# For example:
124	#   do_basic_setup+0x9c/0xbf
125
126	if [[ $module == "" ]] ; then
127		local objfile=$vmlinux
128	elif [[ $aarray_support == true && "${modcache[$module]+isset}" == "isset" ]]; then
129		local objfile=${modcache[$module]}
130	else
131		local objfile=$(find_module)
132		if [[ $objfile == "" ]] ; then
133			echo "WARNING! Modules path isn't set, but is needed to parse this symbol" >&2
134			return
135		fi
136		if [[ $aarray_support == true ]]; then
137			modcache[$module]=$objfile
138		fi
139	fi
140
141	# Remove the englobing parenthesis
142	symbol=${symbol#\(}
143	symbol=${symbol%\)}
144
145	# Strip segment
146	local segment
147	if [[ $symbol == *:* ]] ; then
148		segment=${symbol%%:*}:
149		symbol=${symbol#*:}
150	fi
151
152	# Strip the symbol name so that we could look it up
153	local name=${symbol%+*}
154
155	# Use 'nm vmlinux' to figure out the base address of said symbol.
156	# It's actually faster to call it every time than to load it
157	# all into bash.
158	if [[ $aarray_support == true && "${cache[$module,$name]+isset}" == "isset" ]]; then
159		local base_addr=${cache[$module,$name]}
160	else
161		local base_addr=$(nm "$objfile" 2>/dev/null | awk '$3 == "'$name'" && ($2 == "t" || $2 == "T") {print $1; exit}')
162		if [[ $base_addr == "" ]] ; then
163			# address not found
164			return
165		fi
166		if [[ $aarray_support == true ]]; then
167			cache[$module,$name]="$base_addr"
168		fi
169	fi
170	# Let's start doing the math to get the exact address into the
171	# symbol. First, strip out the symbol total length.
172	local expr=${symbol%/*}
173
174	# Now, replace the symbol name with the base address we found
175	# before.
176	expr=${expr/$name/0x$base_addr}
177
178	# Evaluate it to find the actual address
179	expr=$((expr))
180	local address=$(printf "%x\n" "$expr")
181
182	# Pass it to addr2line to get filename and line number
183	# Could get more than one result
184	if [[ $aarray_support == true && "${cache[$module,$address]+isset}" == "isset" ]]; then
185		local code=${cache[$module,$address]}
186	else
187		local code=$(${ADDR2LINE} -i -e "$objfile" "$address" 2>/dev/null)
188		if [[ $aarray_support == true ]]; then
189			cache[$module,$address]=$code
190		fi
191	fi
192
193	# addr2line doesn't return a proper error code if it fails, so
194	# we detect it using the value it prints so that we could preserve
195	# the offset/size into the function and bail out
196	if [[ $code == "??:0" ]]; then
197		return
198	fi
199
200	# Strip out the base of the path on each line
201	code=$(while read -r line; do echo "${line#$basepath/}"; done <<< "$code")
202
203	# In the case of inlines, move everything to same line
204	code=${code//$'\n'/' '}
205
206	# Demangle if the name looks like a Rust symbol and if
207	# we got a Rust demangler
208	if [[ $name =~ ^_R && $cppfilt != "" ]] ; then
209		name=$("$cppfilt" "$cppfilt_opts" "$name")
210	fi
211
212	# Replace old address with pretty line numbers
213	symbol="$segment$name ($code)"
214}
215
216debuginfod_get_vmlinux() {
217	local vmlinux_buildid=${1##* }
218
219	if [[ $vmlinux != "" ]]; then
220		return
221	fi
222
223	if [[ $vmlinux_buildid =~ ^[0-9a-f]+ ]]; then
224		vmlinux=$(debuginfod-find debuginfo $vmlinux_buildid)
225		if [[ $? -ne 0 ]] ; then
226			echo "ERROR! vmlinux image not found via debuginfod-find" >&2
227			usage
228			exit 2
229		fi
230		return
231	fi
232	echo "ERROR! Build ID for vmlinux not found. Try passing -r or specifying vmlinux" >&2
233	usage
234	exit 2
235}
236
237decode_code() {
238	local scripts=`dirname "${BASH_SOURCE[0]}"`
239
240	echo "$1" | $scripts/decodecode
241}
242
243handle_line() {
244	if [[ $basepath == "auto" && $vmlinux != "" ]] ; then
245		module=""
246		symbol="kernel_init+0x0/0x0"
247		parse_symbol
248		basepath=${symbol#kernel_init (}
249		basepath=${basepath%/init/main.c:*)}
250	fi
251
252	local words
253
254	# Tokenize
255	read -a words <<<"$1"
256
257	# Remove hex numbers. Do it ourselves until it happens in the
258	# kernel
259
260	# We need to know the index of the last element before we
261	# remove elements because arrays are sparse
262	local last=$(( ${#words[@]} - 1 ))
263
264	for i in "${!words[@]}"; do
265		# Remove the address
266		if [[ ${words[$i]} =~ \[\<([^]]+)\>\] ]]; then
267			unset words[$i]
268		fi
269
270		# Format timestamps with tabs
271		if [[ ${words[$i]} == \[ && ${words[$i+1]} == *\] ]]; then
272			unset words[$i]
273			words[$i+1]=$(printf "[%13s\n" "${words[$i+1]}")
274		fi
275	done
276
277	if [[ ${words[$last]} =~ ^[0-9a-f]+\] ]]; then
278		words[$last-1]="${words[$last-1]} ${words[$last]}"
279		unset words[$last]
280		last=$(( $last - 1 ))
281	fi
282
283	if [[ ${words[$last]} =~ \[([^]]+)\] ]]; then
284		module=${words[$last]}
285		module=${module#\[}
286		module=${module%\]}
287		modbuildid=${module#* }
288		module=${module% *}
289		if [[ $modbuildid == $module ]]; then
290			modbuildid=
291		fi
292		symbol=${words[$last-1]}
293		unset words[$last-1]
294	else
295		# The symbol is the last element, process it
296		symbol=${words[$last]}
297		module=
298		modbuildid=
299	fi
300
301	unset words[$last]
302	parse_symbol # modifies $symbol
303
304	# Add up the line number to the symbol
305	echo "${words[@]}" "$symbol $module"
306}
307
308while read line; do
309	# Strip unexpected carriage return at end of line
310	line=${line%$'\r'}
311
312	# Let's see if we have an address in the line
313	if [[ $line =~ \[\<([^]]+)\>\] ]] ||
314	   [[ $line =~ [^+\ ]+\+0x[0-9a-f]+/0x[0-9a-f]+ ]]; then
315		# Translate address to line numbers
316		handle_line "$line"
317	# Is it a code line?
318	elif [[ $line == *Code:* ]]; then
319		decode_code "$line"
320	# Is it a version line?
321	elif [[ -n $debuginfod && $line =~ PID:\ [0-9]+\ Comm: ]]; then
322		debuginfod_get_vmlinux "$line"
323	else
324		# Nothing special in this line, show it as is
325		echo "$line"
326	fi
327done
328