#!/bin/bash # SPDX-License-Identifier: GPL-2.0 # # Translate stack dump function offsets. # # addr2line doesn't work with KASLR addresses. This works similarly to # addr2line, but instead takes the 'func+0x123' format as input: # # $ ./scripts/faddr2line ~/k/vmlinux meminfo_proc_show+0x5/0x568 # meminfo_proc_show+0x5/0x568: # meminfo_proc_show at fs/proc/meminfo.c:27 # # If the address is part of an inlined function, the full inline call chain is # printed: # # $ ./scripts/faddr2line ~/k/vmlinux native_write_msr+0x6/0x27 # native_write_msr+0x6/0x27: # arch_static_branch at arch/x86/include/asm/msr.h:121 # (inlined by) static_key_false at include/linux/jump_label.h:125 # (inlined by) native_write_msr at arch/x86/include/asm/msr.h:125 # # The function size after the '/' in the input is optional, but recommended. # It's used to help disambiguate any duplicate symbol names, which can occur # rarely. If the size is omitted for a duplicate symbol then it's possible for # multiple code sites to be printed: # # $ ./scripts/faddr2line ~/k/vmlinux raw_ioctl+0x5 # raw_ioctl+0x5/0x20: # raw_ioctl at drivers/char/raw.c:122 # # raw_ioctl+0x5/0xb1: # raw_ioctl at net/ipv4/raw.c:876 # # Multiple addresses can be specified on a single command line: # # $ ./scripts/faddr2line ~/k/vmlinux type_show+0x10/45 free_reserved_area+0x90 # type_show+0x10/0x2d: # type_show at drivers/video/backlight/backlight.c:213 # # free_reserved_area+0x90/0x123: # free_reserved_area at mm/page_alloc.c:6429 (discriminator 2) set -o errexit set -o nounset command -v awk >/dev/null 2>&1 || die "awk isn't installed" command -v readelf >/dev/null 2>&1 || die "readelf isn't installed" command -v addr2line >/dev/null 2>&1 || die "addr2line isn't installed" usage() { echo "usage: faddr2line <object file> <func+offset> <func+offset>..." >&2 exit 1 } warn() { echo "$1" >&2 } die() { echo "ERROR: $1" >&2 exit 1 } # Try to figure out the source directory prefix so we can remove it from the # addr2line output. HACK ALERT: This assumes that start_kernel() is in # kernel/init.c! This only works for vmlinux. Otherwise it falls back to # printing the absolute path. find_dir_prefix() { local objfile=$1 local start_kernel_addr=$(readelf -sW $objfile | awk '$8 == "start_kernel" {printf "0x%s", $2}') [[ -z $start_kernel_addr ]] && return local file_line=$(addr2line -e $objfile $start_kernel_addr) [[ -z $file_line ]] && return local prefix=${file_line%init/main.c:*} if [[ -z $prefix ]] || [[ $prefix = $file_line ]]; then return fi DIR_PREFIX=$prefix return 0 } __faddr2line() { local objfile=$1 local func_addr=$2 local dir_prefix=$3 local print_warnings=$4 local func=${func_addr%+*} local offset=${func_addr#*+} offset=${offset%/*} local size= [[ $func_addr =~ "/" ]] && size=${func_addr#*/} if [[ -z $func ]] || [[ -z $offset ]] || [[ $func = $func_addr ]]; then warn "bad func+offset $func_addr" DONE=1 return fi # Go through each of the object's symbols which match the func name. # In rare cases there might be duplicates. file_end=$(size -Ax $objfile | awk '$1 == ".text" {print $2}') while read symbol; do local fields=($symbol) local sym_base=0x${fields[0]} local sym_type=${fields[1]} local sym_end=${fields[3]} # calculate the size local sym_size=$(($sym_end - $sym_base)) if [[ -z $sym_size ]] || [[ $sym_size -le 0 ]]; then warn "bad symbol size: base: $sym_base end: $sym_end" DONE=1 return fi sym_size=0x$(printf %x $sym_size) # calculate the address local addr=$(($sym_base + $offset)) if [[ -z $addr ]] || [[ $addr = 0 ]]; then warn "bad address: $sym_base + $offset" DONE=1 return fi addr=0x$(printf %x $addr) # weed out non-function symbols if [[ $sym_type != t ]] && [[ $sym_type != T ]]; then [[ $print_warnings = 1 ]] && echo "skipping $func address at $addr due to non-function symbol of type '$sym_type'" continue fi # if the user provided a size, make sure it matches the symbol's size if [[ -n $size ]] && [[ $size -ne $sym_size ]]; then [[ $print_warnings = 1 ]] && echo "skipping $func address at $addr due to size mismatch ($size != $sym_size)" continue; fi # make sure the provided offset is within the symbol's range if [[ $offset -gt $sym_size ]]; then [[ $print_warnings = 1 ]] && echo "skipping $func address at $addr due to size mismatch ($offset > $sym_size)" continue fi # separate multiple entries with a blank line [[ $FIRST = 0 ]] && echo FIRST=0 # pass real address to addr2line echo "$func+$offset/$sym_size:" addr2line -fpie $objfile $addr | sed "s; $dir_prefix\(\./\)*; ;" DONE=1 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; }') } [[ $# -lt 2 ]] && usage objfile=$1 [[ ! -f $objfile ]] && die "can't find objfile $objfile" shift DIR_PREFIX=supercalifragilisticexpialidocious find_dir_prefix $objfile FIRST=1 while [[ $# -gt 0 ]]; do func_addr=$1 shift # print any matches found DONE=0 __faddr2line $objfile $func_addr $DIR_PREFIX 0 # if no match was found, print warnings if [[ $DONE = 0 ]]; then __faddr2line $objfile $func_addr $DIR_PREFIX 1 warn "no match for $func_addr" fi done