linux-kernel - [PATCH v3 2/2] kprobes: initialize probed

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Date:   Fri, 27 Oct 2017 17:23:15 +0800
From:   Zhou Chengming <zhouchengming1@...wei.com>
To:     <mhiramat@...nel.org>, <ananth@...ux.vnet.ibm.com>,
        <anil.s.keshavamurthy@...el.com>, <davem@...emloft.net>
CC:     <linux-kernel@...r.kernel.org>, <zhouchengming1@...wei.com>
Subject: [PATCH v3 2/2] kprobes: initialize probed_mod to NULL

When check_kprobe_address_safe() return fail, the probed_mod
should be set to NULL, because no module refcount held. And we
initialize probed_mod to NULL in register_kprobe() for the same reason.

Signed-off-by: Zhou Chengming <zhouchengming1@...wei.com>
---
 kernel/kprobes.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 1eeedac..a04588c 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -1488,6 +1488,7 @@ static int check_kprobe_address_safe(struct kprobe *p,
 		 * its code to prohibit unexpected unloading.
 		 */
 		if (unlikely(!try_module_get(*probed_mod))) {
+			*probed_mod = NULL;
 			ret = -ENOENT;
 			goto out;
 		}
@@ -1514,7 +1515,7 @@ int register_kprobe(struct kprobe *p)
 {
 	int ret;
 	struct kprobe *old_p;
-	struct module *probed_mod;
+	struct module *probed_mod = NULL;
 	kprobe_opcode_t *addr;
 
 	/* Adjust probe address from symbol */
-- 
1.8.3.1