xref: /linux/scripts/decode_stacktrace.sh (revision a36e9f5cfe9eb3a1dce8769c7058251c42705357)
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}
33NM=${UTIL_PREFIX}nm${UTIL_SUFFIX}
34
35if [[ $1 == "-r" ]] ; then
36	vmlinux=""
37	basepath="auto"
38	modpath=""
39	release=$2
40
41	for fn in {,/usr/lib/debug}/boot/vmlinux-$release{,.debug} /lib/modules/$release{,/build}/vmlinux ; do
42		if [ -e "$fn" ] ; then
43			vmlinux=$fn
44			break
45		fi
46	done
47
48	if [[ $vmlinux == "" ]] ; then
49		echo "ERROR! vmlinux image for release $release is not found" >&2
50		usage
51		exit 2
52	fi
53else
54	vmlinux=$1
55	basepath=${2-auto}
56	modpath=$3
57	release=""
58	debuginfod=
59
60	# Can we use debuginfod-find?
61	if type debuginfod-find >/dev/null 2>&1 ; then
62		debuginfod=${1-only}
63	fi
64
65	if [[ $vmlinux == "" && -z $debuginfod ]] ; then
66		echo "ERROR! vmlinux image must be specified" >&2
67		usage
68		exit 1
69	fi
70fi
71
72declare aarray_support=true
73declare -A cache 2>/dev/null
74if [[ $? != 0 ]]; then
75	aarray_support=false
76else
77	declare -A modcache
78fi
79
80find_module() {
81	if [[ -n $debuginfod ]] ; then
82		if [[ -n $modbuildid ]] ; then
83			debuginfod-find debuginfo $modbuildid && return
84		fi
85
86		# Only using debuginfod so don't try to find vmlinux module path
87		if [[ $debuginfod == "only" ]] ; then
88			return
89		fi
90	fi
91
92	if [[ "$modpath" != "" ]] ; then
93		for fn in $(find "$modpath" -name "${module//_/[-_]}.ko*") ; do
94			if ${READELF} -WS "$fn" | grep -qwF .debug_line ; then
95				echo $fn
96				return
97			fi
98		done
99		return 1
100	fi
101
102	modpath=$(dirname "$vmlinux")
103	find_module && return
104
105	if [[ $release == "" ]] ; then
106		release=$(gdb -ex 'print init_uts_ns.name.release' -ex 'quit' -quiet -batch "$vmlinux" 2>/dev/null | sed -n 's/\$1 = "\(.*\)".*/\1/p')
107	fi
108
109	for dn in {/usr/lib/debug,}/lib/modules/$release ; do
110		if [ -e "$dn" ] ; then
111			modpath="$dn"
112			find_module && return
113		fi
114	done
115
116	modpath=""
117	return 1
118}
119
120parse_symbol() {
121	# The structure of symbol at this point is:
122	#   ([name]+[offset]/[total length])
123	#
124	# For example:
125	#   do_basic_setup+0x9c/0xbf
126
127	if [[ $module == "" ]] ; then
128		local objfile=$vmlinux
129	elif [[ $aarray_support == true && "${modcache[$module]+isset}" == "isset" ]]; then
130		local objfile=${modcache[$module]}
131	else
132		local objfile=$(find_module)
133		if [[ $objfile == "" ]] ; then
134			echo "WARNING! Modules path isn't set, but is needed to parse this symbol" >&2
135			return
136		fi
137		if [[ $aarray_support == true ]]; then
138			modcache[$module]=$objfile
139		fi
140	fi
141
142	# Remove the englobing parenthesis
143	symbol=${symbol#\(}
144	symbol=${symbol%\)}
145
146	# Strip segment
147	local segment
148	if [[ $symbol == *:* ]] ; then
149		segment=${symbol%%:*}:
150		symbol=${symbol#*:}
151	fi
152
153	# Strip the symbol name so that we could look it up
154	local name=${symbol%+*}
155
156	# Use 'nm vmlinux' to figure out the base address of said symbol.
157	# It's actually faster to call it every time than to load it
158	# all into bash.
159	if [[ $aarray_support == true && "${cache[$module,$name]+isset}" == "isset" ]]; then
160		local base_addr=${cache[$module,$name]}
161	else
162		local base_addr=$(${NM} "$objfile" 2>/dev/null | awk '$3 == "'$name'" && ($2 == "t" || $2 == "T") {print $1; exit}')
163		if [[ $base_addr == "" ]] ; then
164			# address not found
165			return
166		fi
167		if [[ $aarray_support == true ]]; then
168			cache[$module,$name]="$base_addr"
169		fi
170	fi
171	# Let's start doing the math to get the exact address into the
172	# symbol. First, strip out the symbol total length.
173	local expr=${symbol%/*}
174
175	# Now, replace the symbol name with the base address we found
176	# before.
177	expr=${expr/$name/0x$base_addr}
178
179	# Evaluate it to find the actual address
180	expr=$((expr))
181	local address=$(printf "%x\n" "$expr")
182
183	# Pass it to addr2line to get filename and line number
184	# Could get more than one result
185	if [[ $aarray_support == true && "${cache[$module,$address]+isset}" == "isset" ]]; then
186		local code=${cache[$module,$address]}
187	else
188		local code=$(${ADDR2LINE} -i -e "$objfile" "$address" 2>/dev/null)
189		if [[ $aarray_support == true ]]; then
190			cache[$module,$address]=$code
191		fi
192	fi
193
194	# addr2line doesn't return a proper error code if it fails, so
195	# we detect it using the value it prints so that we could preserve
196	# the offset/size into the function and bail out
197	if [[ $code == "??:0" ]]; then
198		return
199	fi
200
201	# Strip out the base of the path on each line
202	code=$(while read -r line; do echo "${line#$basepath/}"; done <<< "$code")
203
204	# In the case of inlines, move everything to same line
205	code=${code//$'\n'/' '}
206
207	# Demangle if the name looks like a Rust symbol and if
208	# we got a Rust demangler
209	if [[ $name =~ ^_R && $cppfilt != "" ]] ; then
210		name=$("$cppfilt" "$cppfilt_opts" "$name")
211	fi
212
213	# Replace old address with pretty line numbers
214	symbol="$segment$name ($code)"
215}
216
217debuginfod_get_vmlinux() {
218	local vmlinux_buildid=${1##* }
219
220	if [[ $vmlinux != "" ]]; then
221		return
222	fi
223
224	if [[ $vmlinux_buildid =~ ^[0-9a-f]+ ]]; then
225		vmlinux=$(debuginfod-find debuginfo $vmlinux_buildid)
226		if [[ $? -ne 0 ]] ; then
227			echo "ERROR! vmlinux image not found via debuginfod-find" >&2
228			usage
229			exit 2
230		fi
231		return
232	fi
233	echo "ERROR! Build ID for vmlinux not found. Try passing -r or specifying vmlinux" >&2
234	usage
235	exit 2
236}
237
238decode_code() {
239	local scripts=`dirname "${BASH_SOURCE[0]}"`
240
241	echo "$1" | $scripts/decodecode
242}
243
244handle_line() {
245	if [[ $basepath == "auto" && $vmlinux != "" ]] ; then
246		module=""
247		symbol="kernel_init+0x0/0x0"
248		parse_symbol
249		basepath=${symbol#kernel_init (}
250		basepath=${basepath%/init/main.c:*)}
251	fi
252
253	local words
254
255	# Tokenize
256	read -a words <<<"$1"
257
258	# Remove hex numbers. Do it ourselves until it happens in the
259	# kernel
260
261	# We need to know the index of the last element before we
262	# remove elements because arrays are sparse
263	local last=$(( ${#words[@]} - 1 ))
264
265	for i in "${!words[@]}"; do
266		# Remove the address
267		if [[ ${words[$i]} =~ \[\<([^]]+)\>\] ]]; then
268			unset words[$i]
269		fi
270
271		# Format timestamps with tabs
272		if [[ ${words[$i]} == \[ && ${words[$i+1]} == *\] ]]; then
273			unset words[$i]
274			words[$i+1]=$(printf "[%13s\n" "${words[$i+1]}")
275		fi
276	done
277
278	if [[ ${words[$last]} =~ ^[0-9a-f]+\] ]]; then
279		words[$last-1]="${words[$last-1]} ${words[$last]}"
280		unset words[$last]
281		last=$(( $last - 1 ))
282	fi
283
284	if [[ ${words[$last]} =~ \[([^]]+)\] ]]; then
285		module=${words[$last]}
286		# some traces format is "(%pS)", which like "(foo+0x0/0x1 [bar])"
287		# so $module may like "[bar])". Strip the right parenthesis firstly
288		module=${module%\)}
289		module=${module#\[}
290		module=${module%\]}
291		modbuildid=${module#* }
292		module=${module% *}
293		if [[ $modbuildid == $module ]]; then
294			modbuildid=
295		fi
296		symbol=${words[$last-1]}
297		unset words[$last-1]
298	else
299		# The symbol is the last element, process it
300		symbol=${words[$last]}
301		module=
302		modbuildid=
303	fi
304
305	unset words[$last]
306	parse_symbol # modifies $symbol
307
308	# Add up the line number to the symbol
309	echo "${words[@]}" "$symbol $module"
310}
311
312while read line; do
313	# Strip unexpected carriage return at end of line
314	line=${line%$'\r'}
315
316	# Let's see if we have an address in the line
317	if [[ $line =~ \[\<([^]]+)\>\] ]] ||
318	   [[ $line =~ [^+\ ]+\+0x[0-9a-f]+/0x[0-9a-f]+ ]]; then
319		# Translate address to line numbers
320		handle_line "$line"
321	# Is it a code line?
322	elif [[ $line == *Code:* ]]; then
323		decode_code "$line"
324	# Is it a version line?
325	elif [[ -n $debuginfod && $line =~ PID:\ [0-9]+\ Comm: ]]; then
326		debuginfod_get_vmlinux "$line"
327	else
328		# Nothing special in this line, show it as is
329		echo "$line"
330	fi
331done
332