From 66707836062db62756b395d1fb16ab02ff162862 Mon Sep 17 00:00:00 2001 From: Oliver O'Halloran Date: Tue, 16 Feb 2016 17:31:53 +1100 Subject: [PATCH] powerpc/sstep: Fix emulation fall-through There is a switch fallthough in instr_analyze() which can cause an invalid instruction to be emulated as a different, valid, instruction. The rld* (opcode 30) case extracts a sub-opcode from bits 3:1 of the instruction word. However, the only valid values of this field are 001 and 000. These cases are correctly handled, but the others are not which causes execution to fall through into case 31. Breaking out of the switch causes the instruction to be marked as unknown and allows the caller to deal with the invalid instruction in a manner consistent with other invalid instructions. Signed-off-by: Oliver O'Halloran Signed-off-by: Michael Ellerman --- arch/powerpc/lib/sstep.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c index 6d34310f1141..3362299b1859 100644 --- a/arch/powerpc/lib/sstep.c +++ b/arch/powerpc/lib/sstep.c @@ -925,6 +925,7 @@ int __kprobes analyse_instr(struct instruction_op *op, struct pt_regs *regs, } } #endif + break; /* illegal instruction */ case 31: switch ((instr >> 1) & 0x3ff) { -- 2.20.1