From: Masami Hiramatsu <mhiramat@kernel.org>
Date: Tue, 19 Sep 2017 09:59:39 +0000 (+0900)
Subject: kprobes/x86: Move the get_kprobe_ctlblk() into irq-disabled block
X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=cd52edad55fbcd8064877a77d31445b2fb4b85c3;p=openwrt%2Fstaging%2Fblogic.git

kprobes/x86: Move the get_kprobe_ctlblk() into irq-disabled block

Since get_kprobe_ctlblk() accesses per-cpu variables
which calls smp_processor_id(), it must be called under
preempt-disabled or irq-disabled.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E . McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/150581517952.32348.2655896843219158446.stgit@devbox
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---

diff --git a/arch/x86/kernel/kprobes/opt.c b/arch/x86/kernel/kprobes/opt.c
index 0cae7c0f32ec..f55810305f9a 100644
--- a/arch/x86/kernel/kprobes/opt.c
+++ b/arch/x86/kernel/kprobes/opt.c
@@ -154,7 +154,6 @@ STACK_FRAME_NON_STANDARD(optprobe_template_func);
 static void
 optimized_callback(struct optimized_kprobe *op, struct pt_regs *regs)
 {
-	struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
 	unsigned long flags;
 
 	/* This is possible if op is under delayed unoptimizing */
@@ -165,6 +164,7 @@ optimized_callback(struct optimized_kprobe *op, struct pt_regs *regs)
 	if (kprobe_running()) {
 		kprobes_inc_nmissed_count(&op->kp);
 	} else {
+		struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
 		/* Save skipped registers */
 #ifdef CONFIG_X86_64
 		regs->cs = __KERNEL_CS;