mm: bdi: fix race in bdi_class device creation
There is a race from when a device is created with device_create() and
then the drvdata is set with a call to dev_set_drvdata() in which a
sysfs file could be open, yet the drvdata will be NULL, causing all
sorts of bad things to happen.
This patch fixes the problem by using the new function,
device_create_vargs().
Many thanks to Arthur Jones <ajones@riverbed.com> for reporting the bug,
and testing patches out.
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Arthur Jones <ajones@riverbed.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 7c4f9e0..f2e574d 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -172,30 +172,22 @@
int bdi_register(struct backing_dev_info *bdi, struct device *parent,
const char *fmt, ...)
{
- char *name;
va_list args;
int ret = 0;
struct device *dev;
va_start(args, fmt);
- name = kvasprintf(GFP_KERNEL, fmt, args);
+ dev = device_create_vargs(bdi_class, parent, MKDEV(0, 0), bdi, fmt, args);
va_end(args);
-
- if (!name)
- return -ENOMEM;
-
- dev = device_create(bdi_class, parent, MKDEV(0, 0), name);
if (IS_ERR(dev)) {
ret = PTR_ERR(dev);
goto exit;
}
bdi->dev = dev;
- dev_set_drvdata(bdi->dev, bdi);
- bdi_debug_register(bdi, name);
+ bdi_debug_register(bdi, dev_name(dev));
exit:
- kfree(name);
return ret;
}
EXPORT_SYMBOL(bdi_register);