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6977b1a5d6
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: cebf8fd169 ("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>
Linux kernel
============
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In order to build the documentation, use ``make htmldocs`` or
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https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.