[glommer-memcg:slab-common/kmalloc 27/30] fs/proc/stat.c:191:3: warning: large integer implicitly tr

[glommer-memcg:slab-common/kmalloc 27/30] fs/proc/stat.c:191:3: warning: large integer implicitly tr

[Fengguang Wu]

Hi Christoph,

FYI, there are new compile warnings show up in

tree:   git://git.kernel.org/pub/scm/linux/kernel/git/glommer/memcg.git slab-common/kmalloc
head:   f957c1ead131972db578b945e25982f4607da6ba
commit: 1265e4cd1545c612bd0397d3d83fff5301a4beb4 [27/30] CK1 [11/13] Common constants for kmalloc boundaries
config: ia64-defconfig

All warnings:

fs/proc/stat.c: In function 'stat_open':
fs/proc/stat.c:191:3: warning: large integer implicitly truncated to unsigned type [-Woverflow]

vim +191 fs/proc/stat.c

df8106db (Alexey Dobriyan 2008-10-05  179) static int stat_open(struct inode *inode, struct file *file)
df8106db (Alexey Dobriyan 2008-10-05  180) {
59a32e2c (Eric Dumazet    2012-03-23  181) 	unsigned size = 1024 + 128 * num_possible_cpus();
df8106db (Alexey Dobriyan 2008-10-05  182) 	char *buf;
df8106db (Alexey Dobriyan 2008-10-05  183) 	struct seq_file *m;
df8106db (Alexey Dobriyan 2008-10-05  184) 	int res;
df8106db (Alexey Dobriyan 2008-10-05  185) 
59a32e2c (Eric Dumazet    2012-03-23  186) 	/* minimum size to display an interrupt count : 2 bytes */
59a32e2c (Eric Dumazet    2012-03-23  187) 	size += 2 * nr_irqs;
59a32e2c (Eric Dumazet    2012-03-23  188) 
a4dbf0ec (Yuanhan Liu     2011-05-26  189) 	/* don't ask for more than the kmalloc() max size */
a4dbf0ec (Yuanhan Liu     2011-05-26  190) 	if (size > KMALLOC_MAX_SIZE)
a4dbf0ec (Yuanhan Liu     2011-05-26 @191) 		size = KMALLOC_MAX_SIZE;
df8106db (Alexey Dobriyan 2008-10-05  192) 	buf = kmalloc(size, GFP_KERNEL);
df8106db (Alexey Dobriyan 2008-10-05  193) 	if (!buf)
df8106db (Alexey Dobriyan 2008-10-05  194) 		return -ENOMEM;
df8106db (Alexey Dobriyan 2008-10-05  195) 
df8106db (Alexey Dobriyan 2008-10-05  196) 	res = single_open(file, show_stat, NULL);
df8106db (Alexey Dobriyan 2008-10-05  197) 	if (!res) {
df8106db (Alexey Dobriyan 2008-10-05  198) 		m = file->private_data;
df8106db (Alexey Dobriyan 2008-10-05  199) 		m->buf = buf;

---
0-DAY kernel build testing backend         Open Source Technology Centre
Fengguang Wu, Yuanhan Liu                              Intel Corporation

Re: [glommer-memcg:slab-common/kmalloc 27/30] fs/proc/stat.c:191:3: warning: large integer implicitl

[Christoph Lameter]

On Fri, 28 Sep 2012, Fengguang Wu wrote:

> fs/proc/stat.c: In function 'stat_open':
> fs/proc/stat.c:191:3: warning: large integer implicitly truncated to unsigned type [-Woverflow]

I guess we need this patch:

Subject: stat: Use size_t for sizes instead of unsigned

On some platforms (such as IA64) the large page size may results in
slab allocations to be allowed of numbers that do not fit in 32 bit.

Signed-off-by: Christoph Lameter <cl@linux.com>

Index: linux/fs/proc/stat.c
=================================--- linux.orig/fs/proc/stat.c	2012-09-18 12:21:56.301459334 -0500
+++ linux/fs/proc/stat.c	2012-09-28 12:33:29.428759019 -0500
@@ -178,7 +178,7 @@ static int show_stat(struct seq_file *p,

 static int stat_open(struct inode *inode, struct file *file)
 {
-	unsigned size = 1024 + 128 * num_possible_cpus();
+	size_t size = 1024 + 128 * num_possible_cpus();
 	char *buf;
 	struct seq_file *m;
 	int res;