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Date:	Mon, 09 Oct 2006 13:49:38 +0100
From:	Catalin Marinas <catalin.marinas@...il.com>
To:	linux-kernel@...r.kernel.org
Subject: [PATCH 2.6.19-rc1 07/10] Remove some of the kmemleak false positives

From: Catalin Marinas <catalin.marinas@....com>

There are allocations for which the main pointer cannot be found but they
are not memory leaks. This patch fixes some of them.

Signed-off-by: Catalin Marinas <catalin.marinas@....com>
---

 drivers/base/platform.c                |    3 +++
 drivers/char/vt.c                      |    4 ++++
 drivers/hwmon/w83627hf.c               |    4 ++++
 drivers/scsi/hosts.c                   |    3 +++
 drivers/video/console/fbcon.c          |    3 +++
 fs/ext3/dir.c                          |    3 +++
 include/linux/percpu.h                 |    5 +++++
 ipc/util.c                             |    6 ++++++
 kernel/params.c                        |    8 +++++++-
 net/core/dev.c                         |    6 ++++++
 net/core/skbuff.c                      |    3 +++
 net/ipv4/netfilter/ip_conntrack_core.c |    5 +++++
 net/sched/sch_generic.c                |    5 +++++
 13 files changed, 57 insertions(+), 1 deletions(-)

diff --git a/drivers/base/platform.c b/drivers/base/platform.c
index 940ce41..d331b54 100644
--- a/drivers/base/platform.c
+++ b/drivers/base/platform.c
@@ -166,6 +166,9 @@ struct platform_device *platform_device_
 	struct platform_object *pa;
 
 	pa = kzalloc(sizeof(struct platform_object) + strlen(name), GFP_KERNEL);
+	/* kmemleak cannot guess the object type because the block
+	 * size is different from the object size */
+	memleak_typeid(pa, struct platform_object);
 	if (pa) {
 		strcpy(pa->name, name);
 		pa->pdev.name = pa->name;
diff --git a/drivers/char/vt.c b/drivers/char/vt.c
index 8e4413f..614d7e9 100644
--- a/drivers/char/vt.c
+++ b/drivers/char/vt.c
@@ -2640,6 +2640,10 @@ static int __init con_init(void)
 	 */
 	for (currcons = 0; currcons < MIN_NR_CONSOLES; currcons++) {
 		vc_cons[currcons].d = vc = alloc_bootmem(sizeof(struct vc_data));
+		/* kmemleak does not track the memory allocated via
+		 * alloc_bootmem() but this block contains pointers to
+		 * other blocks allocated via kmalloc */
+		memleak_alloc(vc, sizeof(struct vc_data), 1);
 		visual_init(vc, currcons, 1);
 		vc->vc_screenbuf = (unsigned short *)alloc_bootmem(vc->vc_screenbuf_size);
 		vc->vc_kmalloced = 0;
diff --git a/drivers/hwmon/w83627hf.c b/drivers/hwmon/w83627hf.c
index dfdc29c..6f5c70f 100644
--- a/drivers/hwmon/w83627hf.c
+++ b/drivers/hwmon/w83627hf.c
@@ -1097,6 +1097,10 @@ static int w83627hf_detect(struct i2c_ad
 		err = -ENOMEM;
 		goto ERROR1;
 	}
+	/* the pointer to member is stored but the code doesn't use
+	 * container_of for access and the alias need to be
+	 * explicitely declared here */
+	memleak_container(struct w83627hf_data, client);
 
 	new_client = &data->client;
 	i2c_set_clientdata(new_client, data);
diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c
index 68ef163..34b9d41 100644
--- a/drivers/scsi/hosts.c
+++ b/drivers/scsi/hosts.c
@@ -300,6 +300,9 @@ struct Scsi_Host *scsi_host_alloc(struct
 	shost = kzalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
 	if (!shost)
 		return NULL;
+	/* kmemleak cannot guess the object type because the block
+	 * size is different from the object size */
+	memleak_typeid(shost, struct Scsi_Host);
 
 	spin_lock_init(&shost->default_lock);
 	scsi_assign_lock(shost, &shost->default_lock);
diff --git a/drivers/video/console/fbcon.c b/drivers/video/console/fbcon.c
index 8c041da..0f3f513 100644
--- a/drivers/video/console/fbcon.c
+++ b/drivers/video/console/fbcon.c
@@ -2485,6 +2485,9 @@ static int fbcon_set_font(struct vc_data
 	size = h * pitch * charcount;
 
 	new_data = kmalloc(FONT_EXTRA_WORDS * sizeof(int) + size, GFP_USER);
+	/* the stored pointer is different from the address of the
+	 * allocated block because of padding */
+	memleak_padding(new_data, FONT_EXTRA_WORDS * sizeof(int), size);
 
 	if (!new_data)
 		return -ENOMEM;
diff --git a/fs/ext3/dir.c b/fs/ext3/dir.c
index d0b54f3..5a102ce 100644
--- a/fs/ext3/dir.c
+++ b/fs/ext3/dir.c
@@ -349,6 +349,9 @@ int ext3_htree_store_dirent(struct file 
 	new_fn = kzalloc(len, GFP_KERNEL);
 	if (!new_fn)
 		return -ENOMEM;
+	/* kmemleak cannot guess the object type because the block
+	 * size is different from the object size */
+	memleak_typeid(new_fn, struct fname);
 	new_fn->hash = hash;
 	new_fn->minor_hash = minor_hash;
 	new_fn->inode = le32_to_cpu(dirent->inode);
diff --git a/include/linux/percpu.h b/include/linux/percpu.h
index 46ec72f..bcefd93 100644
--- a/include/linux/percpu.h
+++ b/include/linux/percpu.h
@@ -30,7 +30,12 @@ struct percpu_data {
 	void *ptrs[NR_CPUS];
 };
 
+/* pointer disguising messes up the kmemleak objects tracking */
+#ifndef CONFIG_DEBUG_MEMLEAK
 #define __percpu_disguise(pdata) (struct percpu_data *)~(unsigned long)(pdata)
+#else
+#define __percpu_disguise(pdata) (struct percpu_data *)(pdata)
+#endif
 /* 
  * Use this to get to a cpu's version of the per-cpu object dynamically
  * allocated. Non-atomic access to the current CPU's version should
diff --git a/ipc/util.c b/ipc/util.c
index 42479e4..bf58be2 100644
--- a/ipc/util.c
+++ b/ipc/util.c
@@ -492,6 +492,9 @@ void* ipc_rcu_alloc(int size)
 	 */
 	if (rcu_use_vmalloc(size)) {
 		out = vmalloc(HDRLEN_VMALLOC + size);
+		/* the stored pointer is different from the address of
+		 * the allocated block because of padding */
+		memleak_padding(out, HDRLEN_VMALLOC, size);
 		if (out) {
 			out += HDRLEN_VMALLOC;
 			container_of(out, struct ipc_rcu_hdr, data)->is_vmalloc = 1;
@@ -499,6 +502,9 @@ void* ipc_rcu_alloc(int size)
 		}
 	} else {
 		out = kmalloc(HDRLEN_KMALLOC + size, GFP_KERNEL);
+		/* the stored pointer is different from the address of
+		 * the allocated block because of padding */
+		memleak_padding(out, HDRLEN_KMALLOC, size);
 		if (out) {
 			out += HDRLEN_KMALLOC;
 			container_of(out, struct ipc_rcu_hdr, data)->is_vmalloc = 0;
diff --git a/kernel/params.c b/kernel/params.c
index f406655..1510d89 100644
--- a/kernel/params.c
+++ b/kernel/params.c
@@ -548,6 +548,7 @@ static void __init kernel_param_sysfs_se
 {
 	struct module_kobject *mk;
 	int ret;
+	struct module_param_attrs *mp;
 
 	mk = kzalloc(sizeof(struct module_kobject), GFP_KERNEL);
 	BUG_ON(!mk);
@@ -558,8 +559,13 @@ static void __init kernel_param_sysfs_se
 	ret = kobject_register(&mk->kobj);
 	BUG_ON(ret < 0);
 
+	mp = param_sysfs_setup(mk, kparam, num_params, name_skip);
+	/* this structure is not freed but the pointer is
+	 * lost. However, there are other pointers to its members and
+	 * the object has to be kept */
+	memleak_not_leak(mp);
 	/* no need to keep the kobject if no parameter is exported */
-	if (!param_sysfs_setup(mk, kparam, num_params, name_skip)) {
+	if (!mp) {
 		kobject_unregister(&mk->kobj);
 		kfree(mk);
 	}
diff --git a/net/core/dev.c b/net/core/dev.c
index 4d891be..09741ca 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3210,6 +3210,12 @@ struct net_device *alloc_netdev(int size
 	dev = (struct net_device *)
 		(((long)p + NETDEV_ALIGN_CONST) & ~NETDEV_ALIGN_CONST);
 	dev->padded = (char *)dev - (char *)p;
+	/* kmemleak cannot guess the object type because the block
+	 * size is different from the object size. The stored pointer
+	 * is also different from the address of the allocated block
+	 * because of padding */
+	memleak_padding(p, dev->padded, alloc_size - dev->padded);
+	memleak_typeid(p, struct net_device);
 
 	if (sizeof_priv)
 		dev->priv = netdev_priv(dev);
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 3c23760..d657701 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -151,6 +151,9 @@ struct sk_buff *__alloc_skb(unsigned int
 
 	/* Get the HEAD */
 	skb = kmem_cache_alloc(cache, gfp_mask & ~__GFP_DMA);
+	/* the skbuff_fclone_cache contains objects larger than
+	 * "struct sk_buff" and kmemleak cannot guess the type */
+	memleak_typeid(skb, struct sk_buff);
 	if (!skb)
 		goto out;
 
diff --git a/net/ipv4/netfilter/ip_conntrack_core.c b/net/ipv4/netfilter/ip_conntrack_core.c
index 143c466..742c290 100644
--- a/net/ipv4/netfilter/ip_conntrack_core.c
+++ b/net/ipv4/netfilter/ip_conntrack_core.c
@@ -645,6 +645,11 @@ struct ip_conntrack *ip_conntrack_alloc(
 	}
 
 	conntrack = kmem_cache_alloc(ip_conntrack_cachep, GFP_ATOMIC);
+	/* tuplehash_to_ctrack doesn't pass a constant argument to
+	 * container_of and therefore the conntrack->tuplehash[].list
+	 * aliases are ignored */
+	memleak_container(struct ip_conntrack, tuplehash[IP_CT_DIR_ORIGINAL]);
+	memleak_container(struct ip_conntrack, tuplehash[IP_CT_DIR_REPLY]);
 	if (!conntrack) {
 		DEBUGP("Can't allocate conntrack.\n");
 		atomic_dec(&ip_conntrack_count);
diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index 88c6a99..307c3fb 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -434,6 +434,11 @@ struct Qdisc *qdisc_alloc(struct net_dev
 		goto errout;
 	sch = (struct Qdisc *) QDISC_ALIGN((unsigned long) p);
 	sch->padded = (char *) sch - (char *) p;
+	/* kmemleak cannot guess the object type because the block
+	 * size is different from the object size. The stored pointer
+	 * is also different from the address of the allocated block
+	 * because of padding */
+	memleak_padding(p, sch->padded, sizeof(struct Qdisc));
 
 	INIT_LIST_HEAD(&sch->list);
 	skb_queue_head_init(&sch->q);
-
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