From: Shang XiaoJing shangxiaojing@huawei.com
[ Upstream commit 4634c973096a64662a24d9914c47cebc2a8b72f4 ]
Some init function of cdev(like comedi) will call kobject_set_name() before cdev_add(), but won't free the cdev.kobj.name or put the ref cnt of cdev.kobj when cdev_add() failed. As the result, cdev.kobj.name will be leaked.
Free the name of kobject in cdev_add() fail path to prevent memleak. With this fix, the callers don't need to care about freeing the name of kobject if cdev_add() fails.
unreferenced object 0xffff8881000fa8c0 (size 8): comm "modprobe", pid 239, jiffies 4294905173 (age 51.308s) hex dump (first 8 bytes): 63 6f 6d 65 64 69 00 ff comedi.. backtrace: [<000000005f9878f7>] __kmalloc_node_track_caller+0x4c/0x1c0 [<000000000fd70302>] kstrdup+0x3f/0x70 [<000000009428bc33>] kstrdup_const+0x46/0x60 [<00000000ed50d9de>] kvasprintf_const+0xdb/0xf0 [<00000000b2766964>] kobject_set_name_vargs+0x3c/0xe0 [<00000000f2424ef7>] kobject_set_name+0x62/0x90 [<000000005d5a125b>] 0xffffffffa0013098 [<00000000f331e663>] do_one_initcall+0x7a/0x380 [<00000000aa7bac96>] do_init_module+0x5c/0x230 [<000000005fd72335>] load_module+0x227d/0x2420 [<00000000ad550cf1>] __do_sys_finit_module+0xd5/0x140 [<00000000069a60c5>] do_syscall_64+0x3f/0x90 [<00000000c5e0d521>] entry_SYSCALL_64_after_hwframe+0x63/0xcd
Suggested-by: Greg KH gregkh@linuxfoundation.org Signed-off-by: Shang XiaoJing shangxiaojing@huawei.com Link: https://lore.kernel.org/r/20221102072659.23671-1-shangxiaojing@huawei.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- fs/char_dev.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-)
diff --git a/fs/char_dev.c b/fs/char_dev.c index ba0ded7842a7..340e4543b24a 100644 --- a/fs/char_dev.c +++ b/fs/char_dev.c @@ -483,17 +483,24 @@ int cdev_add(struct cdev *p, dev_t dev, unsigned count) p->dev = dev; p->count = count;
- if (WARN_ON(dev == WHITEOUT_DEV)) - return -EBUSY; + if (WARN_ON(dev == WHITEOUT_DEV)) { + error = -EBUSY; + goto err; + }
error = kobj_map(cdev_map, dev, count, NULL, exact_match, exact_lock, p); if (error) - return error; + goto err;
kobject_get(p->kobj.parent);
return 0; + +err: + kfree_const(p->kobj.name); + p->kobj.name = NULL; + return error; }
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