driver core: debug for bad dev_attr_show() return value.

Try to find the culprit who caused
http://bugzilla.kernel.org/show_bug.cgi?id=10150

Cc: <balajirrao@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Andrew Morton 2008-03-04 15:09:07 -08:00 committed by Greg Kroah-Hartman
parent c9698d6b1a
commit 815d2d50da
2 changed files with 12 additions and 1 deletions

View File

@ -19,6 +19,7 @@
#include <linux/kdev_t.h>
#include <linux/notifier.h>
#include <linux/genhd.h>
#include <linux/kallsyms.h>
#include <asm/semaphore.h>
#include "base.h"
@ -68,6 +69,10 @@ static ssize_t dev_attr_show(struct kobject *kobj, struct attribute *attr,
if (dev_attr->show)
ret = dev_attr->show(dev, dev_attr, buf);
if (ret >= (ssize_t)PAGE_SIZE) {
print_symbol("dev_attr_show: %s returned bad count\n",
(unsigned long)dev_attr->show);
}
return ret;
}

View File

@ -12,6 +12,7 @@
#include <linux/module.h>
#include <linux/kobject.h>
#include <linux/kallsyms.h>
#include <linux/namei.h>
#include <linux/poll.h>
#include <linux/list.h>
@ -86,7 +87,12 @@ static int fill_read_buffer(struct dentry * dentry, struct sysfs_buffer * buffer
* The code works fine with PAGE_SIZE return but it's likely to
* indicate truncated result or overflow in normal use cases.
*/
BUG_ON(count >= (ssize_t)PAGE_SIZE);
if (count >= (ssize_t)PAGE_SIZE) {
print_symbol("fill_read_buffer: %s returned bad count\n",
(unsigned long)ops->show);
/* Try to struggle along */
count = PAGE_SIZE - 1;
}
if (count >= 0) {
buffer->needs_read_fill = 0;
buffer->count = count;