[FIX] handling handler_mm_fault retprobe() kernel fail

	- add saving and restoring irq flag

diff --git a/uprobe/arch/asm-x86/swap_uprobes.c b/uprobe/arch/asm-x86/swap_uprobes.c
index 467c6fa..0b03cdb 100644 (file)
--- a/uprobe/arch/asm-x86/swap_uprobes.c
+++ b/uprobe/arch/asm-x86/swap_uprobes.c
@@ -37,6 +37,17 @@ struct uprobe_ctlblk {
 
 static DEFINE_PER_CPU(struct uprobe_ctlblk, ucb) = { 0, NULL };
 
+static void save_current_flags(struct pt_regs *regs)
+{
+       __get_cpu_var(ucb).flags = regs->EREG(flags);
+}
+
+static void restore_current_flags(struct pt_regs *regs)
+{
+       regs->EREG(flags) &= ~IF_MASK;
+       regs->EREG(flags) |= __get_cpu_var(ucb).flags & IF_MASK;
+}
+
 int arch_prepare_uprobe(struct uprobe *up, struct hlist_head *page_list)
 {
        int ret = 0;
@@ -163,7 +174,7 @@ static void resume_execution(struct kprobe *p, struct pt_regs *regs, unsigned lo
        switch (insns[0]) {
                case 0x9c:              /* pushfl */
                        *tos &= ~(TF_MASK | IF_MASK);
-                       *tos |= flags;
+                       *tos |= flags & (TF_MASK | IF_MASK);
                        break;
                case 0xc2:              /* iret/ret/lret */
                case 0xc3:
@@ -237,6 +248,8 @@ static int uprobe_handler(struct pt_regs *regs)
        struct task_struct *task = current;
        pid_t tgid = task->tgid;
 
+       save_current_flags(regs);
+
        addr = (kprobe_opcode_t *)(regs->EREG(ip) - sizeof(kprobe_opcode_t));
        p = get_ukprobe(addr, tgid);
 
@@ -255,7 +268,6 @@ static int uprobe_handler(struct pt_regs *regs)
        }
 
        __get_cpu_var(ucb).p = p;
-       __get_cpu_var(ucb).flags = (regs->EREG(flags) & (TF_MASK | IF_MASK));
 
        return 1;
 }
@@ -266,6 +278,7 @@ static int post_uprobe_handler(struct pt_regs *regs)
        unsigned long flags = __get_cpu_var(ucb).flags;
 
        resume_execution(p, regs, flags);
+       restore_current_flags(regs);
 
        return 1;
 }