uprobes/x86: Change __skip_sstep() to actually skip the whole insn

__skip_sstep() doesn't update regs->ip. Currently this is correct
but only "by accident" and it doesn't skip the whole insn. Change
it to advance ->ip by the length of the detected 0x66*0x90 sequence.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>

1 files changed, 4 insertions, 1 deletions

diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c
index c71025b67462..4e33a35d659e 100644
--- a/arch/x86/kernel/uprobes.c
+++ b/arch/x86/kernel/uprobes.c
@@ -680,8 +680,11 @@ static bool __skip_sstep(struct arch_uprobe *auprobe, struct pt_regs *regs)
                 if (auprobe->insn[i] == 0x66)
                         continue;
 
-                if (auprobe->insn[i] == 0x90)
+                if (auprobe->insn[i] == 0x90) {
+                        regs->ip = uprobe_get_swbp_addr(regs);
+                        regs->ip += i + 1;
                         return true;
+                }
 
                 break;
         }