linux-kernel - [PATCH 02/10] x86, mce: mce_read can check args without mutex

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]

Message-ID: <4AC99361.6060906@jp.fujitsu.com>
Date:	Mon, 05 Oct 2009 15:34:09 +0900
From:	Hidetoshi Seto <seto.hidetoshi@...fujitsu.com>
To:	Huang Ying <ying.huang@...el.com>
CC:	Ingo Molnar <mingo@...e.hu>, "H. Peter Anvin" <hpa@...or.com>,
	Andi Kleen <ak@...ux.intel.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: [PATCH 02/10] x86, mce: mce_read can check args without mutex

Move it before mutex_lock().

Signed-off-by: Hidetoshi Seto <seto.hidetoshi@...fujitsu.com>
---
 arch/x86/kernel/cpu/mcheck/mce.c |   11 ++++-------
 1 files changed, 4 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
index 28e1e14..2d0f9d8 100644
--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -1458,15 +1458,12 @@ static ssize_t mce_read(struct file *filp, char __user *ubuf, size_t usize,
 	unsigned prev, next;
 	int i, err;
 
-	mutex_lock(&mce_read_mutex);
-	next = rcu_dereference(mcelog.next);
-
 	/* Only supports full reads right now */
-	if (*off != 0 || usize < MCE_LOG_LEN*sizeof(struct mce)) {
-		mutex_unlock(&mce_read_mutex);
-
+	if (*off != 0 || usize < sizeof(struct mce) * MCE_LOG_LEN)
 		return -EINVAL;
-	}
+
+	mutex_lock(&mce_read_mutex);
+	next = rcu_dereference(mcelog.next);
 
 	err = 0;
 	prev = 0;
-- 
1.6.4.3


--
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/