1#!/bin/bash 2# SPDX-License-Identifier: GPL-2.0 3# 4# Translate stack dump function offsets. 5# 6# addr2line doesn't work with KASLR addresses. This works similarly to 7# addr2line, but instead takes the 'func+0x123' format as input: 8# 9# $ ./scripts/faddr2line ~/k/vmlinux meminfo_proc_show+0x5/0x568 10# meminfo_proc_show+0x5/0x568: 11# meminfo_proc_show at fs/proc/meminfo.c:27 12# 13# If the address is part of an inlined function, the full inline call chain is 14# printed: 15# 16# $ ./scripts/faddr2line ~/k/vmlinux native_write_msr+0x6/0x27 17# native_write_msr+0x6/0x27: 18# arch_static_branch at arch/x86/include/asm/msr.h:121 19# (inlined by) static_key_false at include/linux/jump_label.h:125 20# (inlined by) native_write_msr at arch/x86/include/asm/msr.h:125 21# 22# The function size after the '/' in the input is optional, but recommended. 23# It's used to help disambiguate any duplicate symbol names, which can occur 24# rarely. If the size is omitted for a duplicate symbol then it's possible for 25# multiple code sites to be printed: 26# 27# $ ./scripts/faddr2line ~/k/vmlinux raw_ioctl+0x5 28# raw_ioctl+0x5/0x20: 29# raw_ioctl at drivers/char/raw.c:122 30# 31# raw_ioctl+0x5/0xb1: 32# raw_ioctl at net/ipv4/raw.c:876 33# 34# Multiple addresses can be specified on a single command line: 35# 36# $ ./scripts/faddr2line ~/k/vmlinux type_show+0x10/45 free_reserved_area+0x90 37# type_show+0x10/0x2d: 38# type_show at drivers/video/backlight/backlight.c:213 39# 40# free_reserved_area+0x90/0x123: 41# free_reserved_area at mm/page_alloc.c:6429 (discriminator 2) 42 43 44set -o errexit 45set -o nounset 46 47usage() { 48 echo "usage: faddr2line [--list] <object file> <func+offset> <func+offset>..." >&2 49 exit 1 50} 51 52warn() { 53 echo "$1" >&2 54} 55 56die() { 57 echo "ERROR: $1" >&2 58 exit 1 59} 60 61READELF="${CROSS_COMPILE:-}readelf" 62ADDR2LINE="${CROSS_COMPILE:-}addr2line" 63AWK="awk" 64 65command -v ${AWK} >/dev/null 2>&1 || die "${AWK} isn't installed" 66command -v ${READELF} >/dev/null 2>&1 || die "${READELF} isn't installed" 67command -v ${ADDR2LINE} >/dev/null 2>&1 || die "${ADDR2LINE} isn't installed" 68 69# Try to figure out the source directory prefix so we can remove it from the 70# addr2line output. HACK ALERT: This assumes that start_kernel() is in 71# init/main.c! This only works for vmlinux. Otherwise it falls back to 72# printing the absolute path. 73find_dir_prefix() { 74 local objfile=$1 75 76 local start_kernel_addr=$(${READELF} --symbols --wide $objfile | ${AWK} '$8 == "start_kernel" {printf "0x%s", $2}') 77 [[ -z $start_kernel_addr ]] && return 78 79 local file_line=$(${ADDR2LINE} -e $objfile $start_kernel_addr) 80 [[ -z $file_line ]] && return 81 82 local prefix=${file_line%init/main.c:*} 83 if [[ -z $prefix ]] || [[ $prefix = $file_line ]]; then 84 return 85 fi 86 87 DIR_PREFIX=$prefix 88 return 0 89} 90 91__faddr2line() { 92 local objfile=$1 93 local func_addr=$2 94 local dir_prefix=$3 95 local print_warnings=$4 96 97 local sym_name=${func_addr%+*} 98 local offset=${func_addr#*+} 99 offset=${offset%/*} 100 local user_size= 101 [[ $func_addr =~ "/" ]] && user_size=${func_addr#*/} 102 103 if [[ -z $sym_name ]] || [[ -z $offset ]] || [[ $sym_name = $func_addr ]]; then 104 warn "bad func+offset $func_addr" 105 DONE=1 106 return 107 fi 108 109 # Go through each of the object's symbols which match the func name. 110 # In rare cases there might be duplicates, in which case we print all 111 # matches. 112 while read line; do 113 local fields=($line) 114 local sym_addr=0x${fields[1]} 115 local sym_elf_size=${fields[2]} 116 local sym_sec=${fields[6]} 117 118 # Get the section size: 119 local sec_size=$(${READELF} --section-headers --wide $objfile | 120 sed 's/\[ /\[/' | 121 ${AWK} -v sec=$sym_sec '$1 == "[" sec "]" { print "0x" $6; exit }') 122 123 if [[ -z $sec_size ]]; then 124 warn "bad section size: section: $sym_sec" 125 DONE=1 126 return 127 fi 128 129 # Calculate the symbol size. 130 # 131 # Unfortunately we can't use the ELF size, because kallsyms 132 # also includes the padding bytes in its size calculation. For 133 # kallsyms, the size calculation is the distance between the 134 # symbol and the next symbol in a sorted list. 135 local sym_size 136 local cur_sym_addr 137 local found=0 138 while read line; do 139 local fields=($line) 140 cur_sym_addr=0x${fields[1]} 141 local cur_sym_elf_size=${fields[2]} 142 local cur_sym_name=${fields[7]:-} 143 144 if [[ $cur_sym_addr = $sym_addr ]] && 145 [[ $cur_sym_elf_size = $sym_elf_size ]] && 146 [[ $cur_sym_name = $sym_name ]]; then 147 found=1 148 continue 149 fi 150 151 if [[ $found = 1 ]]; then 152 sym_size=$(($cur_sym_addr - $sym_addr)) 153 [[ $sym_size -lt $sym_elf_size ]] && continue; 154 found=2 155 break 156 fi 157 done < <(${READELF} --symbols --wide $objfile | ${AWK} -v sec=$sym_sec '$7 == sec' | sort --key=2) 158 159 if [[ $found = 0 ]]; then 160 warn "can't find symbol: sym_name: $sym_name sym_sec: $sym_sec sym_addr: $sym_addr sym_elf_size: $sym_elf_size" 161 DONE=1 162 return 163 fi 164 165 # If nothing was found after the symbol, assume it's the last 166 # symbol in the section. 167 [[ $found = 1 ]] && sym_size=$(($sec_size - $sym_addr)) 168 169 if [[ -z $sym_size ]] || [[ $sym_size -le 0 ]]; then 170 warn "bad symbol size: sym_addr: $sym_addr cur_sym_addr: $cur_sym_addr" 171 DONE=1 172 return 173 fi 174 175 sym_size=0x$(printf %x $sym_size) 176 177 # Calculate the section address from user-supplied offset: 178 local addr=$(($sym_addr + $offset)) 179 if [[ -z $addr ]] || [[ $addr = 0 ]]; then 180 warn "bad address: $sym_addr + $offset" 181 DONE=1 182 return 183 fi 184 addr=0x$(printf %x $addr) 185 186 # If the user provided a size, make sure it matches the symbol's size: 187 if [[ -n $user_size ]] && [[ $user_size -ne $sym_size ]]; then 188 [[ $print_warnings = 1 ]] && 189 echo "skipping $sym_name address at $addr due to size mismatch ($user_size != $sym_size)" 190 continue; 191 fi 192 193 # Make sure the provided offset is within the symbol's range: 194 if [[ $offset -gt $sym_size ]]; then 195 [[ $print_warnings = 1 ]] && 196 echo "skipping $sym_name address at $addr due to size mismatch ($offset > $sym_size)" 197 continue 198 fi 199 200 # In case of duplicates or multiple addresses specified on the 201 # cmdline, separate multiple entries with a blank line: 202 [[ $FIRST = 0 ]] && echo 203 FIRST=0 204 205 echo "$sym_name+$offset/$sym_size:" 206 207 # Pass section address to addr2line and strip absolute paths 208 # from the output: 209 local output=$(${ADDR2LINE} -fpie $objfile $addr | sed "s; $dir_prefix\(\./\)*; ;") 210 [[ -z $output ]] && continue 211 212 # Default output (non --list): 213 if [[ $LIST = 0 ]]; then 214 echo "$output" | while read -r line 215 do 216 echo $line 217 done 218 DONE=1; 219 continue 220 fi 221 222 # For --list, show each line with its corresponding source code: 223 echo "$output" | while read -r line 224 do 225 echo 226 echo $line 227 n=$(echo $line | sed 's/.*:\([0-9]\+\).*/\1/g') 228 n1=$[$n-5] 229 n2=$[$n+5] 230 f=$(echo $line | sed 's/.*at \(.\+\):.*/\1/g') 231 ${AWK} 'NR>=strtonum("'$n1'") && NR<=strtonum("'$n2'") { if (NR=='$n') printf(">%d<", NR); else printf(" %d ", NR); printf("\t%s\n", $0)}' $f 232 done 233 234 DONE=1 235 236 done < <(${READELF} --symbols --wide $objfile | ${AWK} -v fn=$sym_name '$4 == "FUNC" && $8 == fn') 237} 238 239[[ $# -lt 2 ]] && usage 240 241objfile=$1 242 243LIST=0 244[[ "$objfile" == "--list" ]] && LIST=1 && shift && objfile=$1 245 246[[ ! -f $objfile ]] && die "can't find objfile $objfile" 247shift 248 249DIR_PREFIX=supercalifragilisticexpialidocious 250find_dir_prefix $objfile 251 252FIRST=1 253while [[ $# -gt 0 ]]; do 254 func_addr=$1 255 shift 256 257 # print any matches found 258 DONE=0 259 __faddr2line $objfile $func_addr $DIR_PREFIX 0 260 261 # if no match was found, print warnings 262 if [[ $DONE = 0 ]]; then 263 __faddr2line $objfile $func_addr $DIR_PREFIX 1 264 warn "no match for $func_addr" 265 fi 266done 267