xref: /linux/scripts/decode_stacktrace.sh (revision ca55b2fef3a9373fcfc30f82fd26bc7fccbda732)
1#!/bin/bash
2# (c) 2014, Sasha Levin <sasha.levin@oracle.com>
3#set -x
4
5if [[ $# != 2 ]]; then
6	echo "Usage:"
7	echo "	$0 [vmlinux] [base path]"
8	exit 1
9fi
10
11vmlinux=$1
12basepath=$2
13declare -A cache
14
15parse_symbol() {
16	# The structure of symbol at this point is:
17	#   ([name]+[offset]/[total length])
18	#
19	# For example:
20	#   do_basic_setup+0x9c/0xbf
21
22	# Remove the englobing parenthesis
23	symbol=${symbol#\(}
24	symbol=${symbol%\)}
25
26	# Strip the symbol name so that we could look it up
27	local name=${symbol%+*}
28
29	# Use 'nm vmlinux' to figure out the base address of said symbol.
30	# It's actually faster to call it every time than to load it
31	# all into bash.
32	if [[ "${cache[$name]+isset}" == "isset" ]]; then
33		local base_addr=${cache[$name]}
34	else
35		local base_addr=$(nm "$vmlinux" | grep -i ' t ' | awk "/ $name\$/ {print \$1}" | head -n1)
36		cache["$name"]="$base_addr"
37	fi
38	# Let's start doing the math to get the exact address into the
39	# symbol. First, strip out the symbol total length.
40	local expr=${symbol%/*}
41
42	# Now, replace the symbol name with the base address we found
43	# before.
44	expr=${expr/$name/0x$base_addr}
45
46	# Evaluate it to find the actual address
47	expr=$((expr))
48	local address=$(printf "%x\n" "$expr")
49
50	# Pass it to addr2line to get filename and line number
51        # Could get more than one result
52	if [[ "${cache[$address]+isset}" == "isset" ]]; then
53		local code=${cache[$address]}
54	else
55		local code=$(addr2line -i -e "$vmlinux" "$address")
56		cache[$address]=$code
57	fi
58
59	# addr2line doesn't return a proper error code if it fails, so
60	# we detect it using the value it prints so that we could preserve
61	# the offset/size into the function and bail out
62	if [[ $code == "??:0" ]]; then
63		return
64	fi
65
66	# Strip out the base of the path
67	code=${code//$basepath/""}
68
69	# In the case of inlines, move everything to same line
70	code=${code//$'\n'/' '}
71
72	# Replace old address with pretty line numbers
73	symbol="$name ($code)"
74}
75
76decode_code() {
77	local scripts=`dirname "${BASH_SOURCE[0]}"`
78
79	echo "$1" | $scripts/decodecode
80}
81
82handle_line() {
83	local words
84
85	# Tokenize
86	read -a words <<<"$1"
87
88	# Remove hex numbers. Do it ourselves until it happens in the
89	# kernel
90
91	# We need to know the index of the last element before we
92	# remove elements because arrays are sparse
93	local last=$(( ${#words[@]} - 1 ))
94
95	for i in "${!words[@]}"; do
96		# Remove the address
97		if [[ ${words[$i]} =~ \[\<([^]]+)\>\] ]]; then
98			unset words[$i]
99		fi
100
101		# Format timestamps with tabs
102		if [[ ${words[$i]} == \[ && ${words[$i+1]} == *\] ]]; then
103			unset words[$i]
104			words[$i+1]=$(printf "[%13s\n" "${words[$i+1]}")
105		fi
106	done
107
108	# The symbol is the last element, process it
109	symbol=${words[$last]}
110	unset words[$last]
111	parse_symbol # modifies $symbol
112
113	# Add up the line number to the symbol
114	echo "${words[@]}" "$symbol"
115}
116
117while read line; do
118	# Let's see if we have an address in the line
119	if [[ $line =~ \[\<([^]]+)\>\]  ]]; then
120		# Translate address to line numbers
121		handle_line "$line"
122	# Is it a code line?
123	elif [[ $line == *Code:* ]]; then
124                decode_code "$line"
125        else
126		# Nothing special in this line, show it as is
127		echo "$line"
128	fi
129done
130