diff options
author | Borislav Petkov <bp@suse.de> | 2020-10-14 01:48:14 +0200 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-10-14 03:38:26 +0200 |
commit | d72e720a19393eb611a112e4c5c377785dbd645d (patch) | |
tree | 31ad47809ba5c596890c043b8332bd9f5a59122e /scripts/decodecode | |
parent | scripts/spelling.txt: add "arbitrary" typo (diff) | |
download | linux-d72e720a19393eb611a112e4c5c377785dbd645d.tar.xz linux-d72e720a19393eb611a112e4c5c377785dbd645d.zip |
scripts/decodecode: add the capability to supply the program counter
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>
Diffstat (limited to 'scripts/decodecode')
-rwxr-xr-x | scripts/decodecode | 29 |
1 files changed, 22 insertions, 7 deletions
diff --git a/scripts/decodecode b/scripts/decodecode index fbdb325cdf4f..31d884e35f2f 100755 --- a/scripts/decodecode +++ b/scripts/decodecode @@ -6,6 +6,7 @@ # options: set env. variable AFLAGS=options to pass options to "as"; # e.g., to decode an i386 oops on an x86_64 system, use: # AFLAGS=--32 decodecode < 386.oops +# PC=hex - the PC (program counter) the oops points to cleanup() { rm -f $T $T.s $T.o $T.oo $T.aa $T.dis @@ -67,15 +68,19 @@ if [ -z "$ARCH" ]; then esac fi +# Params: (tmp_file, pc_sub) disas() { - ${CROSS_COMPILE}as $AFLAGS -o $1.o $1.s > /dev/null 2>&1 + t=$1 + pc_sub=$2 + + ${CROSS_COMPILE}as $AFLAGS -o $t.o $t.s > /dev/null 2>&1 if [ "$ARCH" = "arm" ]; then if [ $width -eq 2 ]; then OBJDUMPFLAGS="-M force-thumb" fi - ${CROSS_COMPILE}strip $1.o + ${CROSS_COMPILE}strip $t.o fi if [ "$ARCH" = "arm64" ]; then @@ -83,11 +88,18 @@ disas() { type=inst fi - ${CROSS_COMPILE}strip $1.o + ${CROSS_COMPILE}strip $t.o fi - ${CROSS_COMPILE}objdump $OBJDUMPFLAGS -S $1.o | \ - grep -v "/tmp\|Disassembly\|\.text\|^$" > $1.dis 2>&1 + if [ $pc_sub -ne 0 ]; then + if [ $PC ]; then + adj_vma=$(( $PC - $pc_sub )) + OBJDUMPFLAGS="$OBJDUMPFLAGS --adjust-vma=$adj_vma" + fi + fi + + ${CROSS_COMPILE}objdump $OBJDUMPFLAGS -S $t.o | \ + grep -v "/tmp\|Disassembly\|\.text\|^$" > $t.dis 2>&1 } marker=`expr index "$code" "\<"` @@ -95,14 +107,17 @@ if [ $marker -eq 0 ]; then marker=`expr index "$code" "\("` fi + touch $T.oo if [ $marker -ne 0 ]; then + # 2 opcode bytes and a single space + pc_sub=$(( $marker / 3 )) echo All code >> $T.oo echo ======== >> $T.oo beforemark=`echo "$code"` echo -n " .$type 0x" > $T.s echo $beforemark | sed -e 's/ /,0x/g; s/[<>()]//g' >> $T.s - disas $T + disas $T $pc_sub cat $T.dis >> $T.oo rm -f $T.o $T.s $T.dis @@ -114,7 +129,7 @@ echo =========================================== >> $T.aa code=`echo $code | sed -e 's/ [<(]/ /;s/[>)] / /;s/ /,0x/g; s/[>)]$//'` echo -n " .$type 0x" > $T.s echo $code >> $T.s -disas $T +disas $T 0 cat $T.dis >> $T.aa # (lines of whole $T.oo) - (lines of $T.aa, i.e. "Code starting") + 3, |