linux-kernel - [PATCH] block: fix block

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-next>] [day] [month] [year] [list]

Date:	Mon, 14 Jul 2008 15:06:08 +0900
From:	Tejun Heo <tj@...nel.org>
To:	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Jens Axboe <jens.axboe@...cle.com>
Subject: [PATCH] block: fix block_class iteration locking

genhd.c used block_class_lock when it wants to iterate over
block_class.devices list.  This is incorrect as block_class_lock has
nothing to do with synchronization around block_class.devices list, so
there's a window, albeit small, where the list can change while it's
being iterated over.  Fix it by using block_class.sem instead.

Signed-off-by: Tejun Heo <tj@...nel.org>
---
 block/genhd.c |   16 ++++++++--------
 1 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/block/genhd.c b/block/genhd.c
index b922d48..b646e7e 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -234,7 +234,7 @@ void __init printk_all_partitions(void)
 	char buf[BDEVNAME_SIZE];
 	int n;
 
-	mutex_lock(&block_class_lock);
+	down(&block_class.sem);
 	/* For each block device... */
 	list_for_each_entry(dev, &block_class.devices, node) {
 		if (dev->type != &disk_type)
@@ -275,7 +275,7 @@ void __init printk_all_partitions(void)
 		}
 	}
 
-	mutex_unlock(&block_class_lock);
+	up(&block_class.sem);
 }
 
 #ifdef CONFIG_PROC_FS
@@ -285,7 +285,7 @@ static void *part_start(struct seq_file *part, loff_t *pos)
 	loff_t k = *pos;
 	struct device *dev;
 
-	mutex_lock(&block_class_lock);
+	down(&block_class.sem);
 	list_for_each_entry(dev, &block_class.devices, node) {
 		if (dev->type != &disk_type)
 			continue;
@@ -311,7 +311,7 @@ static void *part_next(struct seq_file *part, void *v, loff_t *pos)
 
 static void part_stop(struct seq_file *part, void *v)
 {
-	mutex_unlock(&block_class_lock);
+	up(&block_class.sem);
 }
 
 static int show_partition(struct seq_file *part, void *v)
@@ -533,7 +533,7 @@ static void *diskstats_start(struct seq_file *part, loff_t *pos)
 	loff_t k = *pos;
 	struct device *dev;
 
-	mutex_lock(&block_class_lock);
+	down(&block_class.sem);
 	list_for_each_entry(dev, &block_class.devices, node) {
 		if (dev->type != &disk_type)
 			continue;
@@ -560,7 +560,7 @@ static void *diskstats_next(struct seq_file *part, void *v, loff_t *pos)
 
 static void diskstats_stop(struct seq_file *part, void *v)
 {
-	mutex_unlock(&block_class_lock);
+	up(&block_class.sem);
 }
 
 static int diskstats_show(struct seq_file *s, void *v)
@@ -658,7 +658,7 @@ dev_t blk_lookup_devt(const char *name, int part)
 	struct device *dev;
 	dev_t devt = MKDEV(0, 0);
 
-	mutex_lock(&block_class_lock);
+	down(&block_class.sem);
 	list_for_each_entry(dev, &block_class.devices, node) {
 		if (dev->type != &disk_type)
 			continue;
@@ -671,7 +671,7 @@ dev_t blk_lookup_devt(const char *name, int part)
 			break;
 		}
 	}
-	mutex_unlock(&block_class_lock);
+	up(&block_class.sem);
 
 	return devt;
 }
-- 
1.5.4.5

--
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/