In the Linux kernel, the following vulnerability has been resolved:
driver core: fix resource leak in device_add()
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: 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 kobject_add_internal failed for mac80211_hwsim with -EEXIST, dont try to register things with the same name in the same directory.