From: Yang Yingliang yangyingliang@huawei.com
[ Upstream commit 8c3e8a6bdb5253b97ad532570f8b5db5f7a06407 ]
If class_add_groups() returns error, the 'cp->subsys' need be unregister, and the 'cp' need be freed.
We can not call kset_unregister() here, because the 'cls' will be freed in callback function class_release() and it's also freed in caller's error path, it will cause double free.
So fix this by calling kobject_del() and kfree_const(name) to cleanup kobject. Besides, call kfree() to free the 'cp'.
Fault injection test can trigger this:
unreferenced object 0xffff888102fa8190 (size 8): comm "modprobe", pid 502, jiffies 4294906074 (age 49.296s) hex dump (first 8 bytes): 70 6b 74 63 64 76 64 00 pktcdvd. backtrace: [<00000000e7c7703d>] __kmalloc_track_caller+0x1ae/0x320 [<000000005e4d70bc>] kstrdup+0x3a/0x70 [<00000000c2e5e85a>] kstrdup_const+0x68/0x80 [<000000000049a8c7>] kvasprintf_const+0x10b/0x190 [<0000000029123163>] kobject_set_name_vargs+0x56/0x150 [<00000000747219c9>] kobject_set_name+0xab/0xe0 [<0000000005f1ea4e>] __class_register+0x15c/0x49a
unreferenced object 0xffff888037274000 (size 1024): comm "modprobe", pid 502, jiffies 4294906074 (age 49.296s) hex dump (first 32 bytes): 00 40 27 37 80 88 ff ff 00 40 27 37 80 88 ff ff .@'7.....@'7.... 00 00 00 00 ad 4e ad de ff ff ff ff 00 00 00 00 .....N.......... backtrace: [<00000000151f9600>] kmem_cache_alloc_trace+0x17c/0x2f0 [<00000000ecf3dd95>] __class_register+0x86/0x49a
Fixes: ced6473e7486 ("driver core: class: add class_groups support") Signed-off-by: Yang Yingliang yangyingliang@huawei.com Link: https://lore.kernel.org/r/20221026082803.3458760-1-yangyingliang@huawei.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/base/class.c | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/drivers/base/class.c b/drivers/base/class.c index 54def4e02f00..d36cdbeaa2c8 100644 --- a/drivers/base/class.c +++ b/drivers/base/class.c @@ -185,6 +185,11 @@ int __class_register(struct class *cls, struct lock_class_key *key) } error = class_add_groups(class_get(cls), cls->class_groups); class_put(cls); + if (error) { + kobject_del(&cp->subsys.kobj); + kfree_const(cp->subsys.kobj.name); + kfree(cp); + } return error; } EXPORT_SYMBOL_GPL(__class_register);