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Diffstat (limited to 'arch/x86/kernel/kprobes.c')
-rw-r--r--arch/x86/kernel/kprobes.c43
1 files changed, 25 insertions, 18 deletions
diff --git a/arch/x86/kernel/kprobes.c b/arch/x86/kernel/kprobes.c
index b43bbaebe2c..345a4b1fe14 100644
--- a/arch/x86/kernel/kprobes.c
+++ b/arch/x86/kernel/kprobes.c
@@ -422,14 +422,22 @@ static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs,
static void __kprobes clear_btf(void)
{
- if (test_thread_flag(TIF_DEBUGCTLMSR))
- update_debugctlmsr(0);
+ if (test_thread_flag(TIF_BLOCKSTEP)) {
+ unsigned long debugctl = get_debugctlmsr();
+
+ debugctl &= ~DEBUGCTLMSR_BTF;
+ update_debugctlmsr(debugctl);
+ }
}
static void __kprobes restore_btf(void)
{
- if (test_thread_flag(TIF_DEBUGCTLMSR))
- update_debugctlmsr(current->thread.debugctlmsr);
+ if (test_thread_flag(TIF_BLOCKSTEP)) {
+ unsigned long debugctl = get_debugctlmsr();
+
+ debugctl |= DEBUGCTLMSR_BTF;
+ update_debugctlmsr(debugctl);
+ }
}
void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
@@ -534,20 +542,6 @@ static int __kprobes kprobe_handler(struct pt_regs *regs)
struct kprobe_ctlblk *kcb;
addr = (kprobe_opcode_t *)(regs->ip - sizeof(kprobe_opcode_t));
- if (*addr != BREAKPOINT_INSTRUCTION) {
- /*
- * The breakpoint instruction was removed right
- * after we hit it. Another cpu has removed
- * either a probepoint or a debugger breakpoint
- * at this address. In either case, no further
- * handling of this interrupt is appropriate.
- * Back up over the (now missing) int3 and run
- * the original instruction.
- */
- regs->ip = (unsigned long)addr;
- return 1;
- }
-
/*
* We don't want to be preempted for the entire
* duration of kprobe processing. We conditionally
@@ -579,6 +573,19 @@ static int __kprobes kprobe_handler(struct pt_regs *regs)
setup_singlestep(p, regs, kcb, 0);
return 1;
}
+ } else if (*addr != BREAKPOINT_INSTRUCTION) {
+ /*
+ * The breakpoint instruction was removed right
+ * after we hit it. Another cpu has removed
+ * either a probepoint or a debugger breakpoint
+ * at this address. In either case, no further
+ * handling of this interrupt is appropriate.
+ * Back up over the (now missing) int3 and run
+ * the original instruction.
+ */
+ regs->ip = (unsigned long)addr;
+ preempt_enable_no_resched();
+ return 1;
} else if (kprobe_running()) {
p = __get_cpu_var(current_kprobe);
if (p->break_handler && p->break_handler(p, regs)) {