Commit 977ad481 authored Feb 13, 2015 by Wang Nan Committed by Linus Torvalds Feb 13, 2015

kprobes: set kprobes_all_disarmed earlier to enable re-optimization.



In original code, the probed instruction doesn't get optimized after

echo 0 > /sys/kernel/debug/kprobes/enabled
echo 1 > /sys/kernel/debug/kprobes/enabled

This is because original code checks kprobes_all_disarmed in
optimize_kprobe(), but this flag is turned off after calling that
function.  Therefore, optimize_kprobe() will see kprobes_all_disarmed ==
true and doesn't do the optimization.

This patch simply turns off kprobes_all_disarmed earlier to enable
optimization.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 5125991c

kernel/kprobes.c

+6 −1

Original line number	Diff line number	Diff line
		@@ -2320,6 +2320,12 @@ static void arm_all_kprobes(void)
		if (!kprobes_all_disarmed)
		goto already_enabled;

		/*
		* optimize_kprobe() called by arm_kprobe() checks
		* kprobes_all_disarmed, so set kprobes_all_disarmed before
		* arm_kprobe.
		*/
		kprobes_all_disarmed = false;
		/* Arming kprobes doesn't optimize kprobe itself */
		for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
		head = &kprobe_table[i];
		@@ -2328,7 +2334,6 @@ static void arm_all_kprobes(void)
		arm_kprobe(p);
		}

		kprobes_all_disarmed = false;
		printk(KERN_INFO "Kprobes globally enabled\n");

		already_enabled: