From: Zhengchao Shao shaozhengchao@huawei.com
[ Upstream commit 6977b1a5d67097eaa4d02b0c126c04cc6e8917c0 ]
When calling kobject_add() failed in device_add(), it will call cleanup_glue_dir() to free resource. But in kobject_add(), dev->kobj.parent has been set to NULL. This will cause resource leak.
The process is as follows: device_add() get_device_parent() class_dir_create_and_add() kobject_add() //kobject_get() ... dev->kobj.parent = kobj; ... kobject_add() //failed, but set dev->kobj.parent = NULL ... glue_dir = get_glue_dir(dev) //glue_dir = NULL, and goto //"Error" label ... cleanup_glue_dir() //becaues glue_dir is NULL, not call //kobject_put()
The preceding problem may cause insmod mac80211_hwsim.ko to failed. sysfs: cannot create duplicate filename '/devices/virtual/mac80211_hwsim' Call Trace: <TASK> dump_stack_lvl+0x8e/0xd1 sysfs_warn_dup.cold+0x1c/0x29 sysfs_create_dir_ns+0x224/0x280 kobject_add_internal+0x2aa/0x880 kobject_add+0x135/0x1a0 get_device_parent+0x3d7/0x590 device_add+0x2aa/0x1cb0 device_create_groups_vargs+0x1eb/0x260 device_create+0xdc/0x110 mac80211_hwsim_new_radio+0x31e/0x4790 [mac80211_hwsim] init_mac80211_hwsim+0x48d/0x1000 [mac80211_hwsim] do_one_initcall+0x10f/0x630 do_init_module+0x19f/0x5e0 load_module+0x64b7/0x6eb0 __do_sys_finit_module+0x140/0x200 do_syscall_64+0x35/0x80 entry_SYSCALL_64_after_hwframe+0x46/0xb0 </TASK> kobject_add_internal failed for mac80211_hwsim with -EEXIST, don't try to register things with the same name in the same directory.
Fixes: cebf8fd16900 ("driver core: fix race between creating/querying glue dir and its cleanup") Signed-off-by: Zhengchao Shao shaozhengchao@huawei.com Link: https://lore.kernel.org/r/20221123012042.335252-1-shaozhengchao@huawei.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/base/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/base/core.c b/drivers/base/core.c index e5c15061070b7..9019b81405bf2 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -3451,7 +3451,7 @@ int device_add(struct device *dev) /* we require the name to be set before, and pass NULL */ error = kobject_add(&dev->kobj, dev->kobj.parent, NULL); if (error) { - glue_dir = get_glue_dir(dev); + glue_dir = kobj; goto Error; }