xref: /linux/scripts/decode_stacktrace.sh (revision 3a39d672e7f48b8d6b91a09afa4b55352773b4b5)
1#!/usr/bin/env 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>"
9	echo "	$0 [<vmlinux> [<base_path>|auto [<modules_path>]]]"
10	echo "	$0 -h"
11}
12
13# Try to find a Rust demangler
14if type llvm-cxxfilt >/dev/null 2>&1 ; then
15	cppfilt=llvm-cxxfilt
16elif type c++filt >/dev/null 2>&1 ; then
17	cppfilt=c++filt
18	cppfilt_opts=-i
19fi
20
21UTIL_SUFFIX=
22if [[ -z ${LLVM:-} ]]; then
23	UTIL_PREFIX=${CROSS_COMPILE:-}
24else
25	UTIL_PREFIX=llvm-
26	if [[ ${LLVM} == */ ]]; then
27		UTIL_PREFIX=${LLVM}${UTIL_PREFIX}
28	elif [[ ${LLVM} == -* ]]; then
29		UTIL_SUFFIX=${LLVM}
30	fi
31fi
32
33READELF=${UTIL_PREFIX}readelf${UTIL_SUFFIX}
34ADDR2LINE=${UTIL_PREFIX}addr2line${UTIL_SUFFIX}
35NM=${UTIL_PREFIX}nm${UTIL_SUFFIX}
36
37if [[ $1 == "-h" ]] ; then
38	usage
39	exit 0
40elif [[ $1 == "-r" ]] ; then
41	vmlinux=""
42	basepath="auto"
43	modpath=""
44	release=$2
45
46	for fn in {,/usr/lib/debug}/boot/vmlinux-$release{,.debug} /lib/modules/$release{,/build}/vmlinux ; do
47		if [ -e "$fn" ] ; then
48			vmlinux=$fn
49			break
50		fi
51	done
52
53	if [[ $vmlinux == "" ]] ; then
54		echo "ERROR! vmlinux image for release $release is not found" >&2
55		usage
56		exit 2
57	fi
58else
59	vmlinux=$1
60	basepath=${2-auto}
61	modpath=$3
62	release=""
63	debuginfod=
64
65	# Can we use debuginfod-find?
66	if type debuginfod-find >/dev/null 2>&1 ; then
67		debuginfod=${1-only}
68	fi
69
70	if [[ $vmlinux == "" && -z $debuginfod ]] ; then
71		echo "ERROR! vmlinux image must be specified" >&2
72		usage
73		exit 1
74	fi
75fi
76
77declare aarray_support=true
78declare -A cache 2>/dev/null
79if [[ $? != 0 ]]; then
80	aarray_support=false
81else
82	declare -A modcache
83fi
84
85find_module() {
86	if [[ -n $debuginfod ]] ; then
87		if [[ -n $modbuildid ]] ; then
88			debuginfod-find debuginfo $modbuildid && return
89		fi
90
91		# Only using debuginfod so don't try to find vmlinux module path
92		if [[ $debuginfod == "only" ]] ; then
93			return
94		fi
95	fi
96
97	if [ -z $release ] ; then
98		release=$(gdb -ex 'print init_uts_ns.name.release' -ex 'quit' -quiet -batch "$vmlinux" 2>/dev/null | sed -n 's/\$1 = "\(.*\)".*/\1/p')
99	fi
100	if [ -n "${release}" ] ; then
101		release_dirs="/usr/lib/debug/lib/modules/$release /lib/modules/$release"
102	fi
103
104	found_without_debug_info=false
105	for dir in "$modpath" "$(dirname "$vmlinux")" ${release_dirs}; do
106		if [ -n "${dir}" ] && [ -e "${dir}" ]; then
107			for fn in $(find "$dir" -name "${module//_/[-_]}.ko*") ; do
108				if ${READELF} -WS "$fn" | grep -qwF .debug_line ; then
109					echo $fn
110					return
111				fi
112				found_without_debug_info=true
113			done
114		fi
115	done
116
117	if [[ ${found_without_debug_info} == true ]]; then
118		echo "WARNING! No debugging info in module ${module}, rebuild with DEBUG_KERNEL and DEBUG_INFO" >&2
119	else
120		echo "WARNING! Cannot find .ko for module ${module}, please pass a valid module path" >&2
121	fi
122
123	return 1
124}
125
126parse_symbol() {
127	# The structure of symbol at this point is:
128	#   ([name]+[offset]/[total length])
129	#
130	# For example:
131	#   do_basic_setup+0x9c/0xbf
132
133	if [[ $module == "" ]] ; then
134		local objfile=$vmlinux
135	elif [[ $aarray_support == true && "${modcache[$module]+isset}" == "isset" ]]; then
136		local objfile=${modcache[$module]}
137	else
138		local objfile=$(find_module)
139		if [[ $objfile == "" ]] ; then
140			return
141		fi
142		if [[ $aarray_support == true ]]; then
143			modcache[$module]=$objfile
144		fi
145	fi
146
147	# Remove the englobing parenthesis
148	symbol=${symbol#\(}
149	symbol=${symbol%\)}
150
151	# Strip segment
152	local segment
153	if [[ $symbol == *:* ]] ; then
154		segment=${symbol%%:*}:
155		symbol=${symbol#*:}
156	fi
157
158	# Strip the symbol name so that we could look it up
159	local name=${symbol%+*}
160
161	# Use 'nm vmlinux' to figure out the base address of said symbol.
162	# It's actually faster to call it every time than to load it
163	# all into bash.
164	if [[ $aarray_support == true && "${cache[$module,$name]+isset}" == "isset" ]]; then
165		local base_addr=${cache[$module,$name]}
166	else
167		local base_addr=$(${NM} "$objfile" 2>/dev/null | awk '$3 == "'$name'" && ($2 == "t" || $2 == "T") {print $1; exit}')
168		if [[ $base_addr == "" ]] ; then
169			# address not found
170			return
171		fi
172		if [[ $aarray_support == true ]]; then
173			cache[$module,$name]="$base_addr"
174		fi
175	fi
176	# Let's start doing the math to get the exact address into the
177	# symbol. First, strip out the symbol total length.
178	local expr=${symbol%/*}
179
180	# Now, replace the symbol name with the base address we found
181	# before.
182	expr=${expr/$name/0x$base_addr}
183
184	# Evaluate it to find the actual address
185	expr=$((expr))
186	local address=$(printf "%x\n" "$expr")
187
188	# Pass it to addr2line to get filename and line number
189	# Could get more than one result
190	if [[ $aarray_support == true && "${cache[$module,$address]+isset}" == "isset" ]]; then
191		local code=${cache[$module,$address]}
192	else
193		local code=$(${ADDR2LINE} -i -e "$objfile" "$address" 2>/dev/null)
194		if [[ $aarray_support == true ]]; then
195			cache[$module,$address]=$code
196		fi
197	fi
198
199	# addr2line doesn't return a proper error code if it fails, so
200	# we detect it using the value it prints so that we could preserve
201	# the offset/size into the function and bail out
202	if [[ $code == "??:0" ]]; then
203		return
204	fi
205
206	# Strip out the base of the path on each line
207	code=$(while read -r line; do echo "${line#$basepath/}"; done <<< "$code")
208
209	# In the case of inlines, move everything to same line
210	code=${code//$'\n'/' '}
211
212	# Demangle if the name looks like a Rust symbol and if
213	# we got a Rust demangler
214	if [[ $name =~ ^_R && $cppfilt != "" ]] ; then
215		name=$("$cppfilt" "$cppfilt_opts" "$name")
216	fi
217
218	# Replace old address with pretty line numbers
219	symbol="$segment$name ($code)"
220}
221
222debuginfod_get_vmlinux() {
223	local vmlinux_buildid=${1##* }
224
225	if [[ $vmlinux != "" ]]; then
226		return
227	fi
228
229	if [[ $vmlinux_buildid =~ ^[0-9a-f]+ ]]; then
230		vmlinux=$(debuginfod-find debuginfo $vmlinux_buildid)
231		if [[ $? -ne 0 ]] ; then
232			echo "ERROR! vmlinux image not found via debuginfod-find" >&2
233			usage
234			exit 2
235		fi
236		return
237	fi
238	echo "ERROR! Build ID for vmlinux not found. Try passing -r or specifying vmlinux" >&2
239	usage
240	exit 2
241}
242
243decode_code() {
244	local scripts=`dirname "${BASH_SOURCE[0]}"`
245
246	echo "$1" | $scripts/decodecode
247}
248
249handle_line() {
250	if [[ $basepath == "auto" && $vmlinux != "" ]] ; then
251		module=""
252		symbol="kernel_init+0x0/0x0"
253		parse_symbol
254		basepath=${symbol#kernel_init (}
255		basepath=${basepath%/init/main.c:*)}
256	fi
257
258	local words
259
260	# Tokenize
261	read -a words <<<"$1"
262
263	# Remove hex numbers. Do it ourselves until it happens in the
264	# kernel
265
266	# We need to know the index of the last element before we
267	# remove elements because arrays are sparse
268	local last=$(( ${#words[@]} - 1 ))
269
270	for i in "${!words[@]}"; do
271		# Remove the address
272		if [[ ${words[$i]} =~ \[\<([^]]+)\>\] ]]; then
273			unset words[$i]
274		fi
275
276		# Format timestamps with tabs
277		if [[ ${words[$i]} == \[ && ${words[$i+1]} == *\] ]]; then
278			unset words[$i]
279			words[$i+1]=$(printf "[%13s\n" "${words[$i+1]}")
280		fi
281	done
282
283	if [[ ${words[$last]} =~ ^[0-9a-f]+\] ]]; then
284		words[$last-1]="${words[$last-1]} ${words[$last]}"
285		unset words[$last]
286		last=$(( $last - 1 ))
287	fi
288
289	if [[ ${words[$last]} =~ \[([^]]+)\] ]]; then
290		module=${words[$last]}
291		# some traces format is "(%pS)", which like "(foo+0x0/0x1 [bar])"
292		# so $module may like "[bar])". Strip the right parenthesis firstly
293		module=${module%\)}
294		module=${module#\[}
295		module=${module%\]}
296		modbuildid=${module#* }
297		module=${module% *}
298		if [[ $modbuildid == $module ]]; then
299			modbuildid=
300		fi
301		symbol=${words[$last-1]}
302		unset words[$last-1]
303	else
304		# The symbol is the last element, process it
305		symbol=${words[$last]}
306		module=
307		modbuildid=
308	fi
309
310	unset words[$last]
311	parse_symbol # modifies $symbol
312
313	# Add up the line number to the symbol
314	echo "${words[@]}" "$symbol $module"
315}
316
317while read line; do
318	# Strip unexpected carriage return at end of line
319	line=${line%$'\r'}
320
321	# Let's see if we have an address in the line
322	if [[ $line =~ \[\<([^]]+)\>\] ]] ||
323	   [[ $line =~ [^+\ ]+\+0x[0-9a-f]+/0x[0-9a-f]+ ]]; then
324		# Translate address to line numbers
325		handle_line "$line"
326	# Is it a code line?
327	elif [[ $line == *Code:* ]]; then
328		decode_code "$line"
329	# Is it a version line?
330	elif [[ -n $debuginfod && $line =~ PID:\ [0-9]+\ Comm: ]]; then
331		debuginfod_get_vmlinux "$line"
332	else
333		# Nothing special in this line, show it as is
334		echo "$line"
335	fi
336done
337