From: David Wilder Placing a kprobe on "bc" instruction (s390/s390x) can cause an oops. The instruction length is encoded into the first two bits of the s390 instruction. Kprobe is incorrectly computing the instruction length. The instruction length is used for determining what type of "fix-up" is needed for conditional branch instruction. The problem can bee seen by placing a kprobe on a "bc" instruction that will not branch. The results is that Kprobe incorrectly computes the new instruction pointer (psw.addr) after single stepping the instruction. The problem is corrected with this patch. Signed-off-by: David Wilder Signed-off-by: Martin Schwidefsky Signed-off-by: Heiko Carstens --- arch/s390/kernel/kprobes.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) Index: quilt-2.6/arch/s390/kernel/kprobes.c =================================================================== --- quilt-2.6.orig/arch/s390/kernel/kprobes.c +++ quilt-2.6/arch/s390/kernel/kprobes.c @@ -85,7 +85,7 @@ void __kprobes get_instruction_type(stru ainsn->reg = (*ainsn->insn & 0xf0) >> 4; /* save the instruction length (pop 5-5) in bytes */ - switch (*(__u8 *) (ainsn->insn) >> 4) { + switch (*(__u8 *) (ainsn->insn) >> 6) { case 0: ainsn->ilen = 2; break; -- blue skies, Martin. "Reality continues to ruin my life." - Calvin. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/