[PATCH 4.19 47/48] scripts/decodecode: fix trapping instruction formatting

Greg Kroah-Hartman
2020-05-13T10:04:14Z

From: Ivan Delalande <colona@arista.com>

commit e08df079b23e2e982df15aa340bfbaf50f297504 upstream.

If the trapping instruction contains a ':', for a memory access through
segment registers for example, the sed substitution will insert the '*'
marker in the middle of the instruction instead of the line address:

2b: 65 48 0f c7 0f cmpxchg16b %gs:*(%rdi) <-- trapping instruction

I started to think I had forgotten some quirk of the assembly syntax
before noticing that it was actually coming from the script. Fix it to
add the address marker at the right place for these instructions:

28: 49 8b 06 mov (%r14),%rax
2b:* 65 48 0f c7 0f cmpxchg16b %gs:(%rdi) <-- trapping instruction
30: 0f 94 c0 sete %al

Fixes: 18ff44b189e2 ("scripts/decodecode: make faulting insn ptr more robust")
Signed-off-by: Ivan Delalande <colona@arista.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Borislav Petkov <bp@suse.de>
Link: http://lkml.kernel.org/r/20200419223653.GA31248@visor
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
scripts/decodecode | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/scripts/decodecode
+++ b/scripts/decodecode
@@ -119,7 +119,7 @@ faultlinenum=$(( $(wc -l $T.oo | cut -d
faultline=`cat $T.dis | head -1 | cut -d":" -f2-`
faultline=`echo "$faultline" | sed -e 's/\[/\\\[/g; s/\]/\\\]/g'`

-cat $T.oo | sed -e "${faultlinenum}s/^\(.*:\)\(.*\)/\1\*\2\t\t<-- trapping instruction/"
+cat $T.oo | sed -e "${faultlinenum}s/^\([^:]*:\)\(.*\)/\1\*\2\t\t<-- trapping instruction/"
echo
cat $T.aa
cleanup