blob: 29df825d375c6eb4b5f2ac4d15b5f3df90ae38c4 [file] [log] [blame]
Josh Poimboeuf67326662016-09-19 10:52:14 -05001#!/bin/bash
2#
3# Translate stack dump function offsets.
4#
5# addr2line doesn't work with KASLR addresses. This works similarly to
6# addr2line, but instead takes the 'func+0x123' format as input:
7#
8# $ ./scripts/faddr2line ~/k/vmlinux meminfo_proc_show+0x5/0x568
9# meminfo_proc_show+0x5/0x568:
10# meminfo_proc_show at fs/proc/meminfo.c:27
11#
12# If the address is part of an inlined function, the full inline call chain is
13# printed:
14#
15# $ ./scripts/faddr2line ~/k/vmlinux native_write_msr+0x6/0x27
16# native_write_msr+0x6/0x27:
17# arch_static_branch at arch/x86/include/asm/msr.h:121
18# (inlined by) static_key_false at include/linux/jump_label.h:125
19# (inlined by) native_write_msr at arch/x86/include/asm/msr.h:125
20#
21# The function size after the '/' in the input is optional, but recommended.
22# It's used to help disambiguate any duplicate symbol names, which can occur
23# rarely. If the size is omitted for a duplicate symbol then it's possible for
24# multiple code sites to be printed:
25#
26# $ ./scripts/faddr2line ~/k/vmlinux raw_ioctl+0x5
27# raw_ioctl+0x5/0x20:
28# raw_ioctl at drivers/char/raw.c:122
29#
30# raw_ioctl+0x5/0xb1:
31# raw_ioctl at net/ipv4/raw.c:876
32#
33# Multiple addresses can be specified on a single command line:
34#
35# $ ./scripts/faddr2line ~/k/vmlinux type_show+0x10/45 free_reserved_area+0x90
36# type_show+0x10/0x2d:
37# type_show at drivers/video/backlight/backlight.c:213
38#
39# free_reserved_area+0x90/0x123:
40# free_reserved_area at mm/page_alloc.c:6429 (discriminator 2)
41
42
43set -o errexit
44set -o nounset
45
46command -v awk >/dev/null 2>&1 || die "awk isn't installed"
47command -v readelf >/dev/null 2>&1 || die "readelf isn't installed"
48command -v addr2line >/dev/null 2>&1 || die "addr2line isn't installed"
49
50usage() {
51 echo "usage: faddr2line <object file> <func+offset> <func+offset>..." >&2
52 exit 1
53}
54
55warn() {
56 echo "$1" >&2
57}
58
59die() {
60 echo "ERROR: $1" >&2
61 exit 1
62}
63
64# Try to figure out the source directory prefix so we can remove it from the
65# addr2line output. HACK ALERT: This assumes that start_kernel() is in
66# kernel/init.c! This only works for vmlinux. Otherwise it falls back to
67# printing the absolute path.
68find_dir_prefix() {
69 local objfile=$1
70
71 local start_kernel_addr=$(readelf -sW $objfile | awk '$8 == "start_kernel" {printf "0x%s", $2}')
72 [[ -z $start_kernel_addr ]] && return
73
74 local file_line=$(addr2line -e $objfile $start_kernel_addr)
75 [[ -z $file_line ]] && return
76
77 local prefix=${file_line%init/main.c:*}
78 if [[ -z $prefix ]] || [[ $prefix = $file_line ]]; then
79 return
80 fi
81
82 DIR_PREFIX=$prefix
83 return 0
84}
85
86__faddr2line() {
87 local objfile=$1
88 local func_addr=$2
89 local dir_prefix=$3
90 local print_warnings=$4
91
92 local func=${func_addr%+*}
93 local offset=${func_addr#*+}
94 offset=${offset%/*}
95 local size=
96 [[ $func_addr =~ "/" ]] && size=${func_addr#*/}
97
98 if [[ -z $func ]] || [[ -z $offset ]] || [[ $func = $func_addr ]]; then
99 warn "bad func+offset $func_addr"
100 DONE=1
101 return
102 fi
103
104 # Go through each of the object's symbols which match the func name.
105 # In rare cases there might be duplicates.
106 while read symbol; do
107 local fields=($symbol)
Josh Poimboeufefdb4162016-10-25 09:51:11 -0500108 local sym_base=0x${fields[0]}
109 local sym_type=${fields[1]}
110 local sym_end=0x${fields[3]}
111
112 # calculate the size
113 local sym_size=$(($sym_end - $sym_base))
114 if [[ -z $sym_size ]] || [[ $sym_size -le 0 ]]; then
115 warn "bad symbol size: base: $sym_base end: $sym_end"
116 DONE=1
117 return
118 fi
119 sym_size=0x$(printf %x $sym_size)
Josh Poimboeuf67326662016-09-19 10:52:14 -0500120
121 # calculate the address
122 local addr=$(($sym_base + $offset))
123 if [[ -z $addr ]] || [[ $addr = 0 ]]; then
124 warn "bad address: $sym_base + $offset"
125 DONE=1
126 return
127 fi
Josh Poimboeufefdb4162016-10-25 09:51:11 -0500128 addr=0x$(printf %x $addr)
Josh Poimboeuf67326662016-09-19 10:52:14 -0500129
130 # weed out non-function symbols
Josh Poimboeufefdb4162016-10-25 09:51:11 -0500131 if [[ $sym_type != t ]] && [[ $sym_type != T ]]; then
Josh Poimboeuf67326662016-09-19 10:52:14 -0500132 [[ $print_warnings = 1 ]] &&
Josh Poimboeufefdb4162016-10-25 09:51:11 -0500133 echo "skipping $func address at $addr due to non-function symbol of type '$sym_type'"
Josh Poimboeuf67326662016-09-19 10:52:14 -0500134 continue
135 fi
136
137 # if the user provided a size, make sure it matches the symbol's size
138 if [[ -n $size ]] && [[ $size -ne $sym_size ]]; then
139 [[ $print_warnings = 1 ]] &&
Josh Poimboeufefdb4162016-10-25 09:51:11 -0500140 echo "skipping $func address at $addr due to size mismatch ($size != $sym_size)"
Josh Poimboeuf67326662016-09-19 10:52:14 -0500141 continue;
142 fi
143
144 # make sure the provided offset is within the symbol's range
145 if [[ $offset -gt $sym_size ]]; then
146 [[ $print_warnings = 1 ]] &&
Josh Poimboeufefdb4162016-10-25 09:51:11 -0500147 echo "skipping $func address at $addr due to size mismatch ($offset > $sym_size)"
Josh Poimboeuf67326662016-09-19 10:52:14 -0500148 continue
149 fi
150
151 # separate multiple entries with a blank line
152 [[ $FIRST = 0 ]] && echo
153 FIRST=0
154
Josh Poimboeufefdb4162016-10-25 09:51:11 -0500155 # pass real address to addr2line
156 echo "$func+$offset/$sym_size:"
157 addr2line -fpie $objfile $addr | sed "s; $dir_prefix\(\./\)*; ;"
Josh Poimboeuf67326662016-09-19 10:52:14 -0500158 DONE=1
159
Josh Poimboeufefdb4162016-10-25 09:51:11 -0500160 done < <(nm -n $objfile | awk -v fn=$func '$3 == fn { found=1; line=$0; start=$1; next } found == 1 { found=0; print line, $1 }')
Josh Poimboeuf67326662016-09-19 10:52:14 -0500161}
162
163[[ $# -lt 2 ]] && usage
164
165objfile=$1
166[[ ! -f $objfile ]] && die "can't find objfile $objfile"
167shift
168
169DIR_PREFIX=supercalifragilisticexpialidocious
170find_dir_prefix $objfile
171
172FIRST=1
173while [[ $# -gt 0 ]]; do
174 func_addr=$1
175 shift
176
177 # print any matches found
178 DONE=0
179 __faddr2line $objfile $func_addr $DIR_PREFIX 0
180
181 # if no match was found, print warnings
182 if [[ $DONE = 0 ]]; then
183 __faddr2line $objfile $func_addr $DIR_PREFIX 1
184 warn "no match for $func_addr"
185 fi
186done