From db023ea595015058270be6a62fe60a7b6b5c50d7 Mon Sep 17 00:00:00 2001
From: Oleg Nesterov <oleg@redhat.com>
Date: Fri, 14 Sep 2012 19:05:46 +0200
Subject: uprobes: Move clear_thread_flag(TIF_UPROBE) to uprobe_notify_resume()

Move clear_thread_flag(TIF_UPROBE) from do_notify_resume() to
uprobe_notify_resume() for !CONFIG_UPROBES case.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
---
 arch/x86/kernel/signal.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

(limited to 'arch/x86')

diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c
index b280908a376..0041e5a5293 100644
--- a/arch/x86/kernel/signal.c
+++ b/arch/x86/kernel/signal.c
@@ -785,10 +785,8 @@ do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags)
 		mce_notify_process();
 #endif /* CONFIG_X86_64 && CONFIG_X86_MCE */
 
-	if (thread_info_flags & _TIF_UPROBE) {
-		clear_thread_flag(TIF_UPROBE);
+	if (thread_info_flags & _TIF_UPROBE)
 		uprobe_notify_resume(regs);
-	}
 
 	/* deal with pending signal delivery */
 	if (thread_info_flags & _TIF_SIGPENDING)
-- 
cgit v1.2.3-70-g09d2


From b64b9c937a533f0bfbfc9f6ac93d3c3e2f97ab02 Mon Sep 17 00:00:00 2001
From: Oleg Nesterov <oleg@redhat.com>
Date: Sat, 29 Sep 2012 21:31:08 +0200
Subject: uprobes/x86: Only rep+nop can be emulated correctly

__skip_sstep() correctly detects the "nontrivial" nop insns,
but since it doesn't update regs->ip we can not really skip
"0x0f 0x1f | 0x0f 0x19 | 0x87 0xc0", the probed application
is killed by SIGILL'ed handle_swbp().

Remove these additional checks. If we want to implement this
correctly we need to know the full insn length to update ->ip.

rep* + nop is fine even without updating ->ip.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
---
 arch/x86/kernel/uprobes.c | 16 ++--------------
 1 file changed, 2 insertions(+), 14 deletions(-)

(limited to 'arch/x86')

diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c
index 9538f00827a..aafa5557b39 100644
--- a/arch/x86/kernel/uprobes.c
+++ b/arch/x86/kernel/uprobes.c
@@ -651,31 +651,19 @@ void arch_uprobe_abort_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
 
 /*
  * Skip these instructions as per the currently known x86 ISA.
- * 0x66* { 0x90 | 0x0f 0x1f | 0x0f 0x19 | 0x87 0xc0 }
+ * rep=0x66*; nop=0x90
  */
 static bool __skip_sstep(struct arch_uprobe *auprobe, struct pt_regs *regs)
 {
 	int i;
 
 	for (i = 0; i < MAX_UINSN_BYTES; i++) {
-		if ((auprobe->insn[i] == 0x66))
+		if (auprobe->insn[i] == 0x66)
 			continue;
 
 		if (auprobe->insn[i] == 0x90)
 			return true;
 
-		if (i == (MAX_UINSN_BYTES - 1))
-			break;
-
-		if ((auprobe->insn[i] == 0x0f) && (auprobe->insn[i+1] == 0x1f))
-			return true;
-
-		if ((auprobe->insn[i] == 0x0f) && (auprobe->insn[i+1] == 0x19))
-			return true;
-
-		if ((auprobe->insn[i] == 0x87) && (auprobe->insn[i+1] == 0xc0))
-			return true;
-
 		break;
 	}
 	return false;
-- 
cgit v1.2.3-70-g09d2