linux-kernel - [PATCH 4/8] Add mutex for adding/removing memory blocks

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: <4C9A1360.6030800@austin.ibm.com>
Date:	Wed, 22 Sep 2010 09:32:00 -0500
From:	Nathan Fontenot <nfont@...tin.ibm.com>
To:	linux-kernel@...r.kernel.org, linux-mm@...ck.org,
	linuxppc-dev@...abs.org
CC:	Greg KH <greg@...ah.com>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>,
	Dave Hansen <dave@...ux.vnet.ibm.com>
Subject: [PATCH 4/8] Add mutex for adding/removing memory blocks

Add a new mutex for use in adding and removing of memory blocks.  This
is needed to avoid any race conditions in which the same memory block could
be added and removed at the same time.

Signed-off-by: Nathan Fontenot <nfont@...tin.ibm.com>

---
 drivers/base/memory.c |    7 +++++++
 1 file changed, 7 insertions(+)

Index: linux-next/drivers/base/memory.c
===================================================================
--- linux-next.orig/drivers/base/memory.c	2010-09-21 12:36:45.000000000 -0500
+++ linux-next/drivers/base/memory.c	2010-09-21 12:37:03.000000000 -0500
@@ -27,6 +27,8 @@
 #include <asm/atomic.h>
 #include <asm/uaccess.h>
 
+static DEFINE_MUTEX(mem_sysfs_mutex);
+
 #define MEMORY_CLASS_NAME	"memory"
 
 static struct sysdev_class memory_sysdev_class = {
@@ -485,6 +487,8 @@ static int add_memory_block(int nid, str
 	if (!mem)
 		return -ENOMEM;
 
+	mutex_lock(&mem_sysfs_mutex);
+
 	mem->start_phys_index = __section_nr(section);
 	mem->state = state;
 	atomic_inc(&mem->section_count);
@@ -508,6 +512,7 @@ static int add_memory_block(int nid, str
 			ret = register_mem_sect_under_node(mem, nid);
 	}
 
+	mutex_unlock(&mem_sysfs_mutex);
 	return ret;
 }
 
@@ -516,6 +521,7 @@ int remove_memory_block(unsigned long no
 {
 	struct memory_block *mem;
 
+	mutex_lock(&mem_sysfs_mutex);
 	mem = find_memory_block(section);
 
 	if (atomic_dec_and_test(&mem->section_count)) {
@@ -528,6 +534,7 @@ int remove_memory_block(unsigned long no
 		unregister_memory(mem, section);
 	}
 
+	mutex_unlock(&mem_sysfs_mutex);
 	return 0;
 }


--
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/