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kprobes: set kprobes_all_disarmed earlier to enable re-optimization.

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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>
This commit is contained in:
Wang Nan 2015-02-13 14:40:24 -08:00 committed by Linus Torvalds
parent 5125991c9a
commit 977ad481b6
1 changed files with 6 additions and 1 deletions
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7
kernel/kprobes.c
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@ -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: