mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-11-01 17:08:10 +00:00
f334b60b43
With WARN_ON addition to kobject_init() [ http://kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.19/2.6.19-mm1/dont-use/broken-out/gregkh-driver-kobject-warn.patch ] I started seeing following WARNING on CPU offline followed by online on my x86_64 system. WARNING at lib/kobject.c:172 kobject_init() Call Trace: [<ffffffff8020ab45>] dump_trace+0xaa/0x3ef [<ffffffff8020aec4>] show_trace+0x3a/0x50 [<ffffffff8020b0f6>] dump_stack+0x15/0x17 [<ffffffff80350abc>] kobject_init+0x3f/0x8a [<ffffffff80350be1>] kobject_register+0x1a/0x3e [<ffffffff803bbd89>] sysdev_register+0x5b/0xf9 [<ffffffff80211d0b>] mce_create_device+0x77/0xf4 [<ffffffff80211dc2>] mce_cpu_callback+0x3a/0xe5 [<ffffffff805632fd>] notifier_call_chain+0x26/0x3b [<ffffffff8023f6f3>] raw_notifier_call_chain+0x9/0xb [<ffffffff802519bf>] _cpu_up+0xb4/0xdc [<ffffffff80251a12>] cpu_up+0x2b/0x42 [<ffffffff803bef00>] store_online+0x4a/0x72 [<ffffffff803bb6ce>] sysdev_store+0x24/0x26 [<ffffffff802baaa2>] sysfs_write_file+0xcf/0xfc [<ffffffff8027fc6f>] vfs_write+0xae/0x154 [<ffffffff80280418>] sys_write+0x47/0x6f [<ffffffff8020963e>] system_call+0x7e/0x83 DWARF2 unwinder stuck at system_call+0x7e/0x83 Leftover inexact backtrace: This is a false positive as mce.c is unregistering/registering sysfs interfaces cleanly on hotplug. kref_put() and conditional decrement of refcnt seems to be the root cause for this and the patch below resolves the issue for me. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
64 lines
1.6 KiB
C
64 lines
1.6 KiB
C
/*
|
|
* kref.c - library routines for handling generic reference counted objects
|
|
*
|
|
* Copyright (C) 2004 Greg Kroah-Hartman <greg@kroah.com>
|
|
* Copyright (C) 2004 IBM Corp.
|
|
*
|
|
* based on lib/kobject.c which was:
|
|
* Copyright (C) 2002-2003 Patrick Mochel <mochel@osdl.org>
|
|
*
|
|
* This file is released under the GPLv2.
|
|
*
|
|
*/
|
|
|
|
#include <linux/kref.h>
|
|
#include <linux/module.h>
|
|
|
|
/**
|
|
* kref_init - initialize object.
|
|
* @kref: object in question.
|
|
*/
|
|
void kref_init(struct kref *kref)
|
|
{
|
|
atomic_set(&kref->refcount,1);
|
|
}
|
|
|
|
/**
|
|
* kref_get - increment refcount for object.
|
|
* @kref: object.
|
|
*/
|
|
void kref_get(struct kref *kref)
|
|
{
|
|
WARN_ON(!atomic_read(&kref->refcount));
|
|
atomic_inc(&kref->refcount);
|
|
}
|
|
|
|
/**
|
|
* kref_put - decrement refcount for object.
|
|
* @kref: object.
|
|
* @release: pointer to the function that will clean up the object when the
|
|
* last reference to the object is released.
|
|
* This pointer is required, and it is not acceptable to pass kfree
|
|
* in as this function.
|
|
*
|
|
* Decrement the refcount, and if 0, call release().
|
|
* Return 1 if the object was removed, otherwise return 0. Beware, if this
|
|
* function returns 0, you still can not count on the kref from remaining in
|
|
* memory. Only use the return value if you want to see if the kref is now
|
|
* gone, not present.
|
|
*/
|
|
int kref_put(struct kref *kref, void (*release)(struct kref *kref))
|
|
{
|
|
WARN_ON(release == NULL);
|
|
WARN_ON(release == (void (*)(struct kref *))kfree);
|
|
|
|
if (atomic_dec_and_test(&kref->refcount)) {
|
|
release(kref);
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
EXPORT_SYMBOL(kref_init);
|
|
EXPORT_SYMBOL(kref_get);
|
|
EXPORT_SYMBOL(kref_put);
|