Bug#394697: oops in sysfs file open on boot, root mount impossible

[Jurij Smakov <jurij@wooyd.org>]

Hi,

So far I have tracked the oops to the check_perm() function in 
fs/sysfs/file.c. The oops occurs in try_module_get(), when called from 
check_perm() in the following snippet.

/* Grab the module reference for this attribute if we have one */
if (!try_module_get(attr->owner)) {
	error = -ENODEV;
	goto Done;
}

On failing call attr->owner is set to 0x30300000 (obviously a bogus 
address). Previous calls to try_module_get() from here are all done 
with attr->owner = 0. The complete debugging output just before the 
oops looks like that:

 on entry inode=f79b018c file=f32d8c20
 file->f_dentry=f79e33a0
 filename=uevent
 file->f_dentry->d_parent=f32941b0
 file->f_dentry->d_fsdata=f3245a30
 attr=f32b10c0
 attr->name=f01ad5c0
 attr->name=uevent
 attr->owner=30300000

Best regards,
-- 
Jurij Smakov                                           jurij@wooyd.org
Key: http://www.wooyd.org/pgpkey/                      KeyID: C99E03CC