linux-kernel - [RFC PATCH v2 01/26] kprobes: set kprobes_all_disarmed earlier to enable re-optimization.

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Thu, 12 Feb 2015 20:19:12 +0800
From:	Wang Nan <wangnan0@...wei.com>
To:	<linux@....linux.org.uk>, <tglx@...utronix.de>, <mingo@...hat.com>,
	<hpa@...or.com>, <rostedt@...dmis.org>, <ananth@...ibm.com>,
	<anil.s.keshavamurthy@...el.com>, <davem@...emloft.net>,
	<masami.hiramatsu.pt@...achi.com>, <luto@...capital.net>,
	<keescook@...omium.org>, <oleg@...hat.com>, <wangnan0@...wei.com>,
	<dave.long@...aro.org>, <tixy@...aro.org>, <nico@...aro.org>,
	<yalin.wang2010@...il.com>, <catalin.marinas@....com>,
	<Yalin.Wang@...ymobile.com>, <mark.rutland@....com>,
	<dave.hansen@...ux.intel.com>, <jkenisto@...ibm.com>,
	<anton@...ba.org>, <stefani@...bold.net>, <JBeulich@...e.com>,
	<akpm@...ux-foundation.org>, <rusty@...tcorp.com.au>,
	<peterz@...radead.org>, <prarit@...hat.com>, <fabf@...net.be>,
	<hannes@...xchg.org>
CC:	<x86@...nel.org>, <linux-kernel@...r.kernel.org>,
	<linux-arm-kernel@...ts.infradead.org>, <lizefan@...wei.com>
Subject: [RFC PATCH v2 01/26] 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@...wei.com>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>
Cc: Ingo Molnar <mingo@...nel.org>
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
---
 kernel/kprobes.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 2ca272f..c397900 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -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:
-- 
1.8.4

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/