mirror of
https://github.com/torvalds/linux.git
synced 2024-12-05 10:32:35 +00:00
1d1a0e7c51
There have been some recent reports of faddr2line failures:
$ scripts/faddr2line sound/soundcore.ko sound_devnode+0x5/0x35
bad symbol size: base: 0x0000000000000000 end: 0x0000000000000000
$ ./scripts/faddr2line vmlinux.o enter_from_user_mode+0x24
bad symbol size: base: 0x0000000000005fe0 end: 0x0000000000005fe0
The problem is that faddr2line is based on 'nm', which has a major
limitation: it doesn't know how to distinguish between different text
sections. So if an offset exists in multiple text sections in the
object, it may fail.
Rewrite faddr2line to be section-aware, by basing it on readelf.
Fixes: 67326666e2
("scripts: add script for translating stack dump function offsets")
Reported-by: Kaiwan N Billimoria <kaiwan.billimoria@gmail.com>
Reported-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Link: https://lore.kernel.org/r/29ff99f86e3da965b6e46c1cc2d72ce6528c17c3.1652382321.git.jpoimboe@kernel.org
267 lines
7.4 KiB
Bash
Executable File
267 lines
7.4 KiB
Bash
Executable File
#!/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
|
|
|
|
usage() {
|
|
echo "usage: faddr2line [--list] <object file> <func+offset> <func+offset>..." >&2
|
|
exit 1
|
|
}
|
|
|
|
warn() {
|
|
echo "$1" >&2
|
|
}
|
|
|
|
die() {
|
|
echo "ERROR: $1" >&2
|
|
exit 1
|
|
}
|
|
|
|
READELF="${CROSS_COMPILE:-}readelf"
|
|
ADDR2LINE="${CROSS_COMPILE:-}addr2line"
|
|
AWK="awk"
|
|
|
|
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"
|
|
|
|
# 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
|
|
# init/main.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} --symbols --wide $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=$4
|
|
|
|
local sym_name=${func_addr%+*}
|
|
local offset=${func_addr#*+}
|
|
offset=${offset%/*}
|
|
local user_size=
|
|
[[ $func_addr =~ "/" ]] && user_size=${func_addr#*/}
|
|
|
|
if [[ -z $sym_name ]] || [[ -z $offset ]] || [[ $sym_name = $func_addr ]]; then
|
|
warn "bad func+offset $func_addr"
|
|
DONE=1
|
|
return
|
|
fi
|
|
|
|
# Go through each of the object's symbols which match the func name.
|
|
# In rare cases there might be duplicates, in which case we print all
|
|
# matches.
|
|
while read line; do
|
|
local fields=($line)
|
|
local sym_addr=0x${fields[1]}
|
|
local sym_elf_size=${fields[2]}
|
|
local sym_sec=${fields[6]}
|
|
|
|
# Get the section size:
|
|
local sec_size=$(${READELF} --section-headers --wide $objfile |
|
|
sed 's/\[ /\[/' |
|
|
${AWK} -v sec=$sym_sec '$1 == "[" sec "]" { print "0x" $6; exit }')
|
|
|
|
if [[ -z $sec_size ]]; then
|
|
warn "bad section size: section: $sym_sec"
|
|
DONE=1
|
|
return
|
|
fi
|
|
|
|
# Calculate the symbol size.
|
|
#
|
|
# Unfortunately we can't use the ELF size, because kallsyms
|
|
# also includes the padding bytes in its size calculation. For
|
|
# kallsyms, the size calculation is the distance between the
|
|
# symbol and the next symbol in a sorted list.
|
|
local sym_size
|
|
local cur_sym_addr
|
|
local found=0
|
|
while read line; do
|
|
local fields=($line)
|
|
cur_sym_addr=0x${fields[1]}
|
|
local cur_sym_elf_size=${fields[2]}
|
|
local cur_sym_name=${fields[7]:-}
|
|
|
|
if [[ $cur_sym_addr = $sym_addr ]] &&
|
|
[[ $cur_sym_elf_size = $sym_elf_size ]] &&
|
|
[[ $cur_sym_name = $sym_name ]]; then
|
|
found=1
|
|
continue
|
|
fi
|
|
|
|
if [[ $found = 1 ]]; then
|
|
sym_size=$(($cur_sym_addr - $sym_addr))
|
|
[[ $sym_size -lt $sym_elf_size ]] && continue;
|
|
found=2
|
|
break
|
|
fi
|
|
done < <(${READELF} --symbols --wide $objfile | ${AWK} -v sec=$sym_sec '$7 == sec' | sort --key=2)
|
|
|
|
if [[ $found = 0 ]]; then
|
|
warn "can't find symbol: sym_name: $sym_name sym_sec: $sym_sec sym_addr: $sym_addr sym_elf_size: $sym_elf_size"
|
|
DONE=1
|
|
return
|
|
fi
|
|
|
|
# If nothing was found after the symbol, assume it's the last
|
|
# symbol in the section.
|
|
[[ $found = 1 ]] && sym_size=$(($sec_size - $sym_addr))
|
|
|
|
if [[ -z $sym_size ]] || [[ $sym_size -le 0 ]]; then
|
|
warn "bad symbol size: sym_addr: $sym_addr cur_sym_addr: $cur_sym_addr"
|
|
DONE=1
|
|
return
|
|
fi
|
|
|
|
sym_size=0x$(printf %x $sym_size)
|
|
|
|
# Calculate the section address from user-supplied offset:
|
|
local addr=$(($sym_addr + $offset))
|
|
if [[ -z $addr ]] || [[ $addr = 0 ]]; then
|
|
warn "bad address: $sym_addr + $offset"
|
|
DONE=1
|
|
return
|
|
fi
|
|
addr=0x$(printf %x $addr)
|
|
|
|
# If the user provided a size, make sure it matches the symbol's size:
|
|
if [[ -n $user_size ]] && [[ $user_size -ne $sym_size ]]; then
|
|
[[ $print_warnings = 1 ]] &&
|
|
echo "skipping $sym_name address at $addr due to size mismatch ($user_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 $sym_name address at $addr due to size mismatch ($offset > $sym_size)"
|
|
continue
|
|
fi
|
|
|
|
# In case of duplicates or multiple addresses specified on the
|
|
# cmdline, separate multiple entries with a blank line:
|
|
[[ $FIRST = 0 ]] && echo
|
|
FIRST=0
|
|
|
|
echo "$sym_name+$offset/$sym_size:"
|
|
|
|
# Pass section address to addr2line and strip absolute paths
|
|
# from the output:
|
|
local output=$(${ADDR2LINE} -fpie $objfile $addr | sed "s; $dir_prefix\(\./\)*; ;")
|
|
[[ -z $output ]] && continue
|
|
|
|
# Default output (non --list):
|
|
if [[ $LIST = 0 ]]; then
|
|
echo "$output" | while read -r line
|
|
do
|
|
echo $line
|
|
done
|
|
DONE=1;
|
|
continue
|
|
fi
|
|
|
|
# For --list, show each line with its corresponding source code:
|
|
echo "$output" | while read -r line
|
|
do
|
|
echo
|
|
echo $line
|
|
n=$(echo $line | sed 's/.*:\([0-9]\+\).*/\1/g')
|
|
n1=$[$n-5]
|
|
n2=$[$n+5]
|
|
f=$(echo $line | sed 's/.*at \(.\+\):.*/\1/g')
|
|
${AWK} 'NR>=strtonum("'$n1'") && NR<=strtonum("'$n2'") { if (NR=='$n') printf(">%d<", NR); else printf(" %d ", NR); printf("\t%s\n", $0)}' $f
|
|
done
|
|
|
|
DONE=1
|
|
|
|
done < <(${READELF} --symbols --wide $objfile | ${AWK} -v fn=$sym_name '$4 == "FUNC" && $8 == fn')
|
|
}
|
|
|
|
[[ $# -lt 2 ]] && usage
|
|
|
|
objfile=$1
|
|
|
|
LIST=0
|
|
[[ "$objfile" == "--list" ]] && LIST=1 && shift && 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
|