From: Zhen Lei thunder.leizhen@huawei.com
[ Upstream commit 4d0fe8c52bb3029d83e323c961221156ab98680b ]
When I register a kset in the following way: static struct kset my_kset; kobject_set_name(&my_kset.kobj, "my_kset"); ret = kset_register(&my_kset);
A null pointer dereference exception is occurred: [ 4453.568337] Unable to handle kernel NULL pointer dereference at \ virtual address 0000000000000028 ... ... [ 4453.810361] Call trace: [ 4453.813062] kobject_get_ownership+0xc/0x34 [ 4453.817493] kobject_add_internal+0x98/0x274 [ 4453.822005] kset_register+0x5c/0xb4 [ 4453.825820] my_kobj_init+0x44/0x1000 [my_kset] ... ...
Because I didn't initialize my_kset.kobj.ktype.
According to the description in Documentation/core-api/kobject.rst: - A ktype is the type of object that embeds a kobject. Every structure that embeds a kobject needs a corresponding ktype.
So add sanity check to make sure kset->kobj.ktype is not NULL.
Signed-off-by: Zhen Lei thunder.leizhen@huawei.com Link: https://lore.kernel.org/r/20230805084114.1298-2-thunder.leizhen@huaweicloud.... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- lib/kobject.c | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/lib/kobject.c b/lib/kobject.c index bbbb067de8ecd..b908655c58123 100644 --- a/lib/kobject.c +++ b/lib/kobject.c @@ -814,6 +814,11 @@ int kset_register(struct kset *k) if (!k) return -EINVAL;
+ if (!k->kobj.ktype) { + pr_err("must have a ktype to be initialized properly!\n"); + return -EINVAL; + } + kset_init(k); err = kobject_add_internal(&k->kobj); if (err)