From 0b9e2cac8a56e197d0a9e06268db4c8652d23dd5 Mon Sep 17 00:00:00 2001 From: Prasanna S Panchamukhi Date: Thu, 5 May 2005 16:15:40 -0700 Subject: [PATCH] Kprobes: Incorrect handling of probes on ret/lret instruction Kprobes could not handle the insertion of a probe on the ret/lret instruction and used to oops after single stepping since kprobes was modifying eip/rip incorrectly. Adjustment of eip/rip is not required after single stepping in case of ret/lret instruction, because eip/rip points to the correct location after execution of the ret/lret instruction. This patch fixes the above problem. Signed-off-by: Prasanna S Panchamukhi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/i386/kernel/kprobes.c | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'arch/i386/kernel') diff --git a/arch/i386/kernel/kprobes.c b/arch/i386/kernel/kprobes.c index 67168165924..59ff9b45506 100644 --- a/arch/i386/kernel/kprobes.c +++ b/arch/i386/kernel/kprobes.c @@ -217,6 +217,13 @@ static void resume_execution(struct kprobe *p, struct pt_regs *regs) *tos &= ~(TF_MASK | IF_MASK); *tos |= kprobe_old_eflags; break; + case 0xc3: /* ret/lret */ + case 0xcb: + case 0xc2: + case 0xca: + regs->eflags &= ~TF_MASK; + /* eip is already adjusted, no more changes required*/ + return; case 0xe8: /* call relative - Fix return addr */ *tos = orig_eip + (*tos - copy_eip); break; -- cgit v1.2.3-70-g09d2