[PATCH 2.6.19 07/10] Remove some of the kmemleak false positives

From: Catalin Marinas
Date: Thu Nov 30 2006 - 18:02:19 EST

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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@xxxxxxxxx>
---

arch/i386/kernel/setup.c | 2 ++
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 +++++
14 files changed, 59 insertions(+), 1 deletions(-)

diff --git a/arch/i386/kernel/setup.c b/arch/i386/kernel/setup.c
index 141041d..610a725 100644
--- a/arch/i386/kernel/setup.c
+++ b/arch/i386/kernel/setup.c
@@ -1487,6 +1487,8 @@ static __init int add_pcspkr(void)
int ret;

pd = platform_device_alloc("pcspkr", -1);
+ /* mark it as not a leak since this device doesn't need to be freed */
+ memleak_not_leak(pd);
if (!pd)
return -ENOMEM;

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 302174b..b482cac 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 600e3d3..899776c 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 cd8bb14..6ac2b7e 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 81c426a..8ee5c01 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 b8b1063..247bbe6 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 8b848aa..6013147 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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Next message: Catalin Marinas: "[PATCH 2.6.19 09/10] Simple testing for kmemleak"
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