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 47command -v awk >/dev/null 2>&1 || die "awk isn't installed" 48command -v readelf >/dev/null 2>&1 || die "readelf isn't installed" 49command -v addr2line >/dev/null 2>&1 || die "addr2line isn't installed" 50 51usage() { 52 echo "usage: faddr2line <object file> <func+offset> <func+offset>..." >&2 53 exit 1 54} 55 56warn() { 57 echo "$1" >&2 58} 59 60die() { 61 echo "ERROR: $1" >&2 62 exit 1 63} 64 65# Try to figure out the source directory prefix so we can remove it from the 66# addr2line output. HACK ALERT: This assumes that start_kernel() is in 67# kernel/init.c! This only works for vmlinux. Otherwise it falls back to 68# printing the absolute path. 69find_dir_prefix() { 70 local objfile=$1 71 72 local start_kernel_addr=$(readelf -sW $objfile | awk '$8 == "start_kernel" {printf "0x%s", $2}') 73 [[ -z $start_kernel_addr ]] && return 74 75 local file_line=$(addr2line -e $objfile $start_kernel_addr) 76 [[ -z $file_line ]] && return 77 78 local prefix=${file_line%init/main.c:*} 79 if [[ -z $prefix ]] || [[ $prefix = $file_line ]]; then 80 return 81 fi 82 83 DIR_PREFIX=$prefix 84 return 0 85} 86 87__faddr2line() { 88 local objfile=$1 89 local func_addr=$2 90 local dir_prefix=$3 91 local print_warnings=$4 92 93 local func=${func_addr%+*} 94 local offset=${func_addr#*+} 95 offset=${offset%/*} 96 local size= 97 [[ $func_addr =~ "/" ]] && size=${func_addr#*/} 98 99 if [[ -z $func ]] || [[ -z $offset ]] || [[ $func = $func_addr ]]; then 100 warn "bad func+offset $func_addr" 101 DONE=1 102 return 103 fi 104 105 # Go through each of the object's symbols which match the func name. 106 # In rare cases there might be duplicates. 107 file_end=$(size -Ax $objfile | awk '$1 == ".text" {print $2}') 108 while read symbol; do 109 local fields=($symbol) 110 local sym_base=0x${fields[0]} 111 local sym_type=${fields[1]} 112 local sym_end=${fields[3]} 113 114 # calculate the size 115 local sym_size=$(($sym_end - $sym_base)) 116 if [[ -z $sym_size ]] || [[ $sym_size -le 0 ]]; then 117 warn "bad symbol size: base: $sym_base end: $sym_end" 118 DONE=1 119 return 120 fi 121 sym_size=0x$(printf %x $sym_size) 122 123 # calculate the address 124 local addr=$(($sym_base + $offset)) 125 if [[ -z $addr ]] || [[ $addr = 0 ]]; then 126 warn "bad address: $sym_base + $offset" 127 DONE=1 128 return 129 fi 130 addr=0x$(printf %x $addr) 131 132 # weed out non-function symbols 133 if [[ $sym_type != t ]] && [[ $sym_type != T ]]; then 134 [[ $print_warnings = 1 ]] && 135 echo "skipping $func address at $addr due to non-function symbol of type '$sym_type'" 136 continue 137 fi 138 139 # if the user provided a size, make sure it matches the symbol's size 140 if [[ -n $size ]] && [[ $size -ne $sym_size ]]; then 141 [[ $print_warnings = 1 ]] && 142 echo "skipping $func address at $addr due to size mismatch ($size != $sym_size)" 143 continue; 144 fi 145 146 # make sure the provided offset is within the symbol's range 147 if [[ $offset -gt $sym_size ]]; then 148 [[ $print_warnings = 1 ]] && 149 echo "skipping $func address at $addr due to size mismatch ($offset > $sym_size)" 150 continue 151 fi 152 153 # separate multiple entries with a blank line 154 [[ $FIRST = 0 ]] && echo 155 FIRST=0 156 157 # pass real address to addr2line 158 echo "$func+$offset/$sym_size:" 159 addr2line -fpie $objfile $addr | sed "s; $dir_prefix\(\./\)*; ;" 160 DONE=1 161 162 done < <(nm -n $objfile | awk -v fn=$func -v end=$file_end '$3 == fn { found=1; line=$0; start=$1; next } found == 1 { found=0; print line, "0x"$1 } END {if (found == 1) print line, end; }') 163} 164 165[[ $# -lt 2 ]] && usage 166 167objfile=$1 168[[ ! -f $objfile ]] && die "can't find objfile $objfile" 169shift 170 171DIR_PREFIX=supercalifragilisticexpialidocious 172find_dir_prefix $objfile 173 174FIRST=1 175while [[ $# -gt 0 ]]; do 176 func_addr=$1 177 shift 178 179 # print any matches found 180 DONE=0 181 __faddr2line $objfile $func_addr $DIR_PREFIX 0 182 183 # if no match was found, print warnings 184 if [[ $DONE = 0 ]]; then 185 __faddr2line $objfile $func_addr $DIR_PREFIX 1 186 warn "no match for $func_addr" 187 fi 188done 189