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: $1" >&2 58 exit 1 59} 60 61UTIL_SUFFIX="" 62if [[ "${LLVM:-}" == "" ]]; then 63 UTIL_PREFIX=${CROSS_COMPILE:-} 64else 65 UTIL_PREFIX=llvm- 66 67 if [[ "${LLVM}" == *"/" ]]; then 68 UTIL_PREFIX=${LLVM}${UTIL_PREFIX} 69 elif [[ "${LLVM}" == "-"* ]]; then 70 UTIL_SUFFIX=${LLVM} 71 fi 72fi 73 74READELF="${UTIL_PREFIX}readelf${UTIL_SUFFIX}" 75ADDR2LINE="${UTIL_PREFIX}addr2line${UTIL_SUFFIX}" 76AWK="awk" 77GREP="grep" 78 79command -v ${AWK} >/dev/null 2>&1 || die "${AWK} isn't installed" 80command -v ${READELF} >/dev/null 2>&1 || die "${READELF} isn't installed" 81command -v ${ADDR2LINE} >/dev/null 2>&1 || die "${ADDR2LINE} isn't installed" 82 83# Try to figure out the source directory prefix so we can remove it from the 84# addr2line output. HACK ALERT: This assumes that start_kernel() is in 85# init/main.c! This only works for vmlinux. Otherwise it falls back to 86# printing the absolute path. 87find_dir_prefix() { 88 local objfile=$1 89 90 local start_kernel_addr=$(echo "${ELF_SYMS}" | sed 's/\[.*\]//' | 91 ${AWK} '$8 == "start_kernel" {printf "0x%s", $2}') 92 [[ -z $start_kernel_addr ]] && return 93 94 local file_line=$(${ADDR2LINE} -e $objfile $start_kernel_addr) 95 [[ -z $file_line ]] && return 96 97 local prefix=${file_line%init/main.c:*} 98 if [[ -z $prefix ]] || [[ $prefix = $file_line ]]; then 99 return 100 fi 101 102 DIR_PREFIX=$prefix 103 return 0 104} 105 106run_readelf() { 107 local objfile=$1 108 local out=$(${READELF} --file-header --section-headers --symbols --wide $objfile) 109 110 # This assumes that readelf first prints the file header, then the section headers, then the symbols. 111 # Note: It seems that GNU readelf does not prefix section headers with the "There are X section headers" 112 # line when multiple options are given, so let's also match with the "Section Headers:" line. 113 ELF_FILEHEADER=$(echo "${out}" | sed -n '/There are [0-9]* section headers, starting at offset\|Section Headers:/q;p') 114 ELF_SECHEADERS=$(echo "${out}" | sed -n '/There are [0-9]* section headers, starting at offset\|Section Headers:/,$p' | sed -n '/Symbol table .* contains [0-9]* entries:/q;p') 115 ELF_SYMS=$(echo "${out}" | sed -n '/Symbol table .* contains [0-9]* entries:/,$p') 116} 117 118check_vmlinux() { 119 # vmlinux uses absolute addresses in the section table rather than 120 # section offsets. 121 IS_VMLINUX=0 122 local file_type=$(echo "${ELF_FILEHEADER}" | 123 ${AWK} '$1 == "Type:" { print $2; exit }') 124 if [[ $file_type = "EXEC" ]] || [[ $file_type == "DYN" ]]; then 125 IS_VMLINUX=1 126 fi 127} 128 129init_addr2line() { 130 local objfile=$1 131 132 check_vmlinux 133 134 ADDR2LINE_ARGS="--functions --pretty-print --inlines --addresses --exe=$objfile" 135 if [[ $IS_VMLINUX = 1 ]]; then 136 # If the executable file is vmlinux, we don't pass section names to 137 # addr2line, so we can launch it now as a single long-running process. 138 coproc ADDR2LINE_PROC (${ADDR2LINE} ${ADDR2LINE_ARGS}) 139 fi 140} 141 142run_addr2line() { 143 local addr=$1 144 local sec_name=$2 145 146 if [[ $IS_VMLINUX = 1 ]]; then 147 # We send to the addr2line process: (1) the address, then (2) a sentinel 148 # value, i.e., something that can't be interpreted as a valid address 149 # (i.e., ","). This causes addr2line to write out: (1) the answer for 150 # our address, then (2) either "?? ??:0" or "0x0...0: ..." (if 151 # using binutils' addr2line), or "," (if using LLVM's addr2line). 152 echo ${addr} >& "${ADDR2LINE_PROC[1]}" 153 echo "," >& "${ADDR2LINE_PROC[1]}" 154 local first_line 155 read -r first_line <& "${ADDR2LINE_PROC[0]}" 156 ADDR2LINE_OUT=$(echo "${first_line}" | sed 's/^0x[0-9a-fA-F]*: //') 157 while read -r line <& "${ADDR2LINE_PROC[0]}"; do 158 if [[ "$line" == "?? ??:0" ]] || [[ "$line" == "," ]] || [[ $(echo "$line" | ${GREP} "^0x00*: ") ]]; then 159 break 160 fi 161 ADDR2LINE_OUT+=$'\n'$(echo "$line" | sed 's/^0x[0-9a-fA-F]*: //') 162 done 163 else 164 # Run addr2line as a single invocation. 165 local sec_arg 166 [[ -z $sec_name ]] && sec_arg="" || sec_arg="--section=${sec_name}" 167 ADDR2LINE_OUT=$(${ADDR2LINE} ${ADDR2LINE_ARGS} ${sec_arg} ${addr} | sed 's/^0x[0-9a-fA-F]*: //') 168 fi 169} 170 171__faddr2line() { 172 local objfile=$1 173 local func_addr=$2 174 local dir_prefix=$3 175 local print_warnings=$4 176 177 local sym_name=${func_addr%+*} 178 local func_offset=${func_addr#*+} 179 func_offset=${func_offset%/*} 180 local user_size= 181 [[ $func_addr =~ "/" ]] && user_size=${func_addr#*/} 182 183 if [[ -z $sym_name ]] || [[ -z $func_offset ]] || [[ $sym_name = $func_addr ]]; then 184 warn "bad func+offset $func_addr" 185 DONE=1 186 return 187 fi 188 189 # Go through each of the object's symbols which match the func name. 190 # In rare cases there might be duplicates, in which case we print all 191 # matches. 192 while read line; do 193 local fields=($line) 194 local sym_addr=0x${fields[1]} 195 local sym_elf_size=${fields[2]} 196 local sym_sec=${fields[6]} 197 local sec_size 198 local sec_name 199 200 # Get the section size: 201 sec_size=$(echo "${ELF_SECHEADERS}" | sed 's/\[ /\[/' | 202 ${AWK} -v sec=$sym_sec '$1 == "[" sec "]" { print "0x" $6; exit }') 203 204 if [[ -z $sec_size ]]; then 205 warn "bad section size: section: $sym_sec" 206 DONE=1 207 return 208 fi 209 210 # Get the section name: 211 sec_name=$(echo "${ELF_SECHEADERS}" | sed 's/\[ /\[/' | 212 ${AWK} -v sec=$sym_sec '$1 == "[" sec "]" { print $2; exit }') 213 214 if [[ -z $sec_name ]]; then 215 warn "bad section name: section: $sym_sec" 216 DONE=1 217 return 218 fi 219 220 # Calculate the symbol size. 221 # 222 # Unfortunately we can't use the ELF size, because kallsyms 223 # also includes the padding bytes in its size calculation. For 224 # kallsyms, the size calculation is the distance between the 225 # symbol and the next symbol in a sorted list. 226 local sym_size 227 local cur_sym_addr 228 local found=0 229 while read line; do 230 local fields=($line) 231 cur_sym_addr=0x${fields[1]} 232 local cur_sym_elf_size=${fields[2]} 233 local cur_sym_name=${fields[7]:-} 234 235 # is_mapping_symbol(cur_sym_name) 236 if [[ ${cur_sym_name} =~ ^(\.L|L0|\$) ]]; then 237 continue 238 fi 239 240 if [[ $cur_sym_addr = $sym_addr ]] && 241 [[ $cur_sym_elf_size = $sym_elf_size ]] && 242 [[ $cur_sym_name = $sym_name ]]; then 243 found=1 244 continue 245 fi 246 247 if [[ $found = 1 ]]; then 248 sym_size=$(($cur_sym_addr - $sym_addr)) 249 [[ $sym_size -lt $sym_elf_size ]] && continue; 250 found=2 251 break 252 fi 253 done < <(echo "${ELF_SYMS}" | sed 's/\[.*\]//' | ${AWK} -v sec=$sym_sec '$7 == sec' | sort --key=2) 254 255 if [[ $found = 0 ]]; then 256 warn "can't find symbol: sym_name: $sym_name sym_sec: $sym_sec sym_addr: $sym_addr sym_elf_size: $sym_elf_size" 257 DONE=1 258 return 259 fi 260 261 # If nothing was found after the symbol, assume it's the last 262 # symbol in the section. 263 [[ $found = 1 ]] && sym_size=$(($sec_size - $sym_addr)) 264 265 if [[ -z $sym_size ]] || [[ $sym_size -le 0 ]]; then 266 warn "bad symbol size: sym_addr: $sym_addr cur_sym_addr: $cur_sym_addr" 267 DONE=1 268 return 269 fi 270 271 sym_size=0x$(printf %x $sym_size) 272 273 # Calculate the address from user-supplied offset: 274 local addr=$(($sym_addr + $func_offset)) 275 if [[ -z $addr ]] || [[ $addr = 0 ]]; then 276 warn "bad address: $sym_addr + $func_offset" 277 DONE=1 278 return 279 fi 280 addr=0x$(printf %x $addr) 281 282 # If the user provided a size, make sure it matches the symbol's size: 283 if [[ -n $user_size ]] && [[ $user_size -ne $sym_size ]]; then 284 [[ $print_warnings = 1 ]] && 285 echo "skipping $sym_name address at $addr due to size mismatch ($user_size != $sym_size)" 286 continue; 287 fi 288 289 # Make sure the provided offset is within the symbol's range: 290 if [[ $func_offset -gt $sym_size ]]; then 291 [[ $print_warnings = 1 ]] && 292 echo "skipping $sym_name address at $addr due to size mismatch ($func_offset > $sym_size)" 293 continue 294 fi 295 296 # In case of duplicates or multiple addresses specified on the 297 # cmdline, separate multiple entries with a blank line: 298 [[ $FIRST = 0 ]] && echo 299 FIRST=0 300 301 echo "$sym_name+$func_offset/$sym_size:" 302 303 # Pass section address to addr2line and strip absolute paths 304 # from the output: 305 run_addr2line $addr $sec_name 306 local output=$(echo "${ADDR2LINE_OUT}" | sed "s; $dir_prefix\(\./\)*; ;") 307 [[ -z $output ]] && continue 308 309 # Default output (non --list): 310 if [[ $LIST = 0 ]]; then 311 echo "$output" | while read -r line 312 do 313 echo $line 314 done 315 DONE=1; 316 continue 317 fi 318 319 # For --list, show each line with its corresponding source code: 320 echo "$output" | while read -r line 321 do 322 echo 323 echo $line 324 n=$(echo $line | sed 's/.*:\([0-9]\+\).*/\1/g') 325 n1=$[$n-5] 326 n2=$[$n+5] 327 f=$(echo $line | sed 's/.*at \(.\+\):.*/\1/g') 328 ${AWK} 'NR>=strtonum("'$n1'") && NR<=strtonum("'$n2'") { if (NR=='$n') printf(">%d<", NR); else printf(" %d ", NR); printf("\t%s\n", $0)}' $f 329 done 330 331 DONE=1 332 333 done < <(echo "${ELF_SYMS}" | sed 's/\[.*\]//' | ${AWK} -v fn=$sym_name '$8 == fn') 334} 335 336[[ $# -lt 2 ]] && usage 337 338objfile=$1 339 340LIST=0 341[[ "$objfile" == "--list" ]] && LIST=1 && shift && objfile=$1 342 343[[ ! -f $objfile ]] && die "can't find objfile $objfile" 344shift 345 346run_readelf $objfile 347 348echo "${ELF_SECHEADERS}" | ${GREP} -q '\.debug_info' || die "CONFIG_DEBUG_INFO not enabled" 349 350init_addr2line $objfile 351 352DIR_PREFIX=supercalifragilisticexpialidocious 353find_dir_prefix $objfile 354 355FIRST=1 356while [[ $# -gt 0 ]]; do 357 func_addr=$1 358 shift 359 360 # print any matches found 361 DONE=0 362 __faddr2line $objfile $func_addr $DIR_PREFIX 0 363 364 # if no match was found, print warnings 365 if [[ $DONE = 0 ]]; then 366 __faddr2line $objfile $func_addr $DIR_PREFIX 1 367 warn "no match for $func_addr" 368 fi 369done 370