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d72e720a19
So that comparing with objdump output from vmlinux can ease pinpointing where the trapping instruction actually is. An example is better than a thousand words: $ PC=0xffffffff8329a927 ./scripts/decodecode < ~/tmp/syz/gfs2.splat [ 477.379104][T23917] Code: 48 83 ec 28 48 89 3c 24 48 89 54 24 08 e8 c1 b4 4a fe 48 8d bb 00 01 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 97 05 00 00 48 8b 9b 00 01 00 00 48 85 db 0f 84 All code ======== ffffffff8329a8fd: 48 83 ec 28 sub $0x28,%rsp ffffffff8329a901: 48 89 3c 24 mov %rdi,(%rsp) ffffffff8329a905: 48 89 54 24 08 mov %rdx,0x8(%rsp) ffffffff8329a90a: e8 c1 b4 4a fe callq 0xffffffff81745dd0 ffffffff8329a90f: 48 8d bb 00 01 00 00 lea 0x100(%rbx),%rdi ffffffff8329a916: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax ffffffff8329a91d: fc ff df ffffffff8329a920: 48 89 fa mov %rdi,%rdx ffffffff8329a923: 48 c1 ea 03 shr $0x3,%rdx ffffffff8329a927:* 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) <-- trapping instruction ffffffff8329a92b: 0f 85 97 05 00 00 jne 0xffffffff8329aec8 ffffffff8329a931: 48 8b 9b 00 01 00 00 mov 0x100(%rbx),%rbx ffffffff8329a938: 48 85 db test %rbx,%rbx ffffffff8329a93b: 0f .byte 0xf ffffffff8329a93c: 84 .byte 0x84 Signed-off-by: Borislav Petkov <bp@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Marc Zyngier <maz@misterjones.org> Cc: Will Deacon <will@kernel.org> Cc: Rabin Vincent <rabin@rab.in> Link: https://lkml.kernel.org/r/20200930111416.GF6810@zn.tnic Link: https://lkml.kernel.org/r/20200929113238.GC21110@zn.tnic Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
147 lines
2.9 KiB
Bash
Executable file
147 lines
2.9 KiB
Bash
Executable file
#!/bin/sh
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# SPDX-License-Identifier: GPL-2.0
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# Disassemble the Code: line in Linux oopses
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# usage: decodecode < oops.file
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#
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# options: set env. variable AFLAGS=options to pass options to "as";
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# e.g., to decode an i386 oops on an x86_64 system, use:
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# AFLAGS=--32 decodecode < 386.oops
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# PC=hex - the PC (program counter) the oops points to
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cleanup() {
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rm -f $T $T.s $T.o $T.oo $T.aa $T.dis
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exit 1
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}
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die() {
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echo "$@"
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exit 1
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}
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trap cleanup EXIT
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T=`mktemp` || die "cannot create temp file"
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code=
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cont=
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while read i ; do
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case "$i" in
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*Code:*)
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code=$i
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cont=yes
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;;
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*)
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[ -n "$cont" ] && {
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xdump="$(echo $i | grep '^[[:xdigit:]<>[:space:]]\+$')"
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if [ -n "$xdump" ]; then
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code="$code $xdump"
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else
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cont=
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fi
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}
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;;
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esac
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done
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if [ -z "$code" ]; then
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rm $T
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exit
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fi
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echo $code
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code=`echo $code | sed -e 's/.*Code: //'`
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width=`expr index "$code" ' '`
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width=$((($width-1)/2))
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case $width in
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1) type=byte ;;
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2) type=2byte ;;
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4) type=4byte ;;
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esac
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if [ -z "$ARCH" ]; then
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case `uname -m` in
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aarch64*) ARCH=arm64 ;;
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arm*) ARCH=arm ;;
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esac
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fi
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# Params: (tmp_file, pc_sub)
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disas() {
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t=$1
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pc_sub=$2
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${CROSS_COMPILE}as $AFLAGS -o $t.o $t.s > /dev/null 2>&1
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if [ "$ARCH" = "arm" ]; then
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if [ $width -eq 2 ]; then
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OBJDUMPFLAGS="-M force-thumb"
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fi
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${CROSS_COMPILE}strip $t.o
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fi
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if [ "$ARCH" = "arm64" ]; then
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if [ $width -eq 4 ]; then
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type=inst
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fi
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${CROSS_COMPILE}strip $t.o
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fi
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if [ $pc_sub -ne 0 ]; then
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if [ $PC ]; then
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adj_vma=$(( $PC - $pc_sub ))
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OBJDUMPFLAGS="$OBJDUMPFLAGS --adjust-vma=$adj_vma"
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fi
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fi
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${CROSS_COMPILE}objdump $OBJDUMPFLAGS -S $t.o | \
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grep -v "/tmp\|Disassembly\|\.text\|^$" > $t.dis 2>&1
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}
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marker=`expr index "$code" "\<"`
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if [ $marker -eq 0 ]; then
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marker=`expr index "$code" "\("`
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fi
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touch $T.oo
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if [ $marker -ne 0 ]; then
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# 2 opcode bytes and a single space
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pc_sub=$(( $marker / 3 ))
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echo All code >> $T.oo
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echo ======== >> $T.oo
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beforemark=`echo "$code"`
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echo -n " .$type 0x" > $T.s
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echo $beforemark | sed -e 's/ /,0x/g; s/[<>()]//g' >> $T.s
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disas $T $pc_sub
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cat $T.dis >> $T.oo
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rm -f $T.o $T.s $T.dis
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# and fix code at-and-after marker
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code=`echo "$code" | cut -c$((${marker} + 1))-`
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fi
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echo Code starting with the faulting instruction > $T.aa
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echo =========================================== >> $T.aa
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code=`echo $code | sed -e 's/ [<(]/ /;s/[>)] / /;s/ /,0x/g; s/[>)]$//'`
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echo -n " .$type 0x" > $T.s
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echo $code >> $T.s
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disas $T 0
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cat $T.dis >> $T.aa
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# (lines of whole $T.oo) - (lines of $T.aa, i.e. "Code starting") + 3,
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# i.e. the title + the "===..=" line (sed is counting from 1, 0 address is
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# special)
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faultlinenum=$(( $(wc -l $T.oo | cut -d" " -f1) - \
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$(wc -l $T.aa | cut -d" " -f1) + 3))
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faultline=`cat $T.dis | head -1 | cut -d":" -f2-`
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faultline=`echo "$faultline" | sed -e 's/\[/\\\[/g; s/\]/\\\]/g'`
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cat $T.oo | sed -e "${faultlinenum}s/^\([^:]*:\)\(.*\)/\1\*\2\t\t<-- trapping instruction/"
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echo
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cat $T.aa
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cleanup
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