Commit 9a09f261 authored Sep 19, 2017 by Masami Hiramatsu Committed by Ingo Molnar Sep 28, 2017

kprobes/x86: Disable preemption in optprobe

Disable preemption in optprobe handler as described
in Documentation/kprobes.txt, which says:

  "Probe handlers are run with preemption 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/150581525942.32348.6359217983269060829.stgit@devbox

Signed-off-by: Ingo Molnar <mingo@kernel.org>

parent e863d539

arch/x86/kernel/kprobes/opt.c

+2 −0

Original line number	Original line	Diff line number	Diff line
	@@ -161,6 +161,7 @@ optimized_callback(struct optimized_kprobe op, struct pt_regs regs)
	return;		return;

	local_irq_save(flags);		local_irq_save(flags);
			preempt_disable();
	if (kprobe_running()) {		if (kprobe_running()) {
	kprobes_inc_nmissed_count(&op->kp);		kprobes_inc_nmissed_count(&op->kp);
	} else {		} else {
	@@ -180,6 +181,7 @@ optimized_callback(struct optimized_kprobe op, struct pt_regs regs)
	opt_pre_handler(&op->kp, regs);		opt_pre_handler(&op->kp, regs);
	__this_cpu_write(current_kprobe, NULL);		__this_cpu_write(current_kprobe, NULL);
	}		}
			preempt_enable_no_resched();
	local_irq_restore(flags);		local_irq_restore(flags);
	}		}
	NOKPROBE_SYMBOL(optimized_callback);		NOKPROBE_SYMBOL(optimized_callback);