Hi greg,
>How did you ever trigger this error case?
When try to register the same class twice.
>I don't like mucking about in the root of the kobject name structure, as who
>knows what is really happening there. Isn't there some other "better" way to
>resolve this?
I try to use below patch to fix issue, but it'll cause double free issue and
change code a lot if fix double free issue, I think there is no better
function which can be used to
free the kobject name.
diff --git a/lib/kobject.c b/lib/kobject.c
index cb14aea..a2711d1 100644
--- a/lib/kobject.c
+++ b/lib/kobject.c
@@ -794,8 +794,10 @@ int kset_register(struct kset *k)
kset_init(k);
err = kobject_add_internal(&k->kobj);
- if (err)
+ if (err) {
+ kobject_put(&k->kobj);
return err;
+ }
Thanks,
Lin
-----Original Message-----
From: Greg KH [mailto:[email protected]]
Sent: Tuesday, June 9, 2015 4:56 AM
To: Chen, Lin Z
Cc: [email protected]; He, Bo; [email protected]
Subject: Re: [PATCH] class: Free the kobject.name if kset_register fails
On Mon, Jun 08, 2015 at 03:49:37PM +0800, Chen Lin Z wrote:
> Fix a memory leak by freeing the memory allocated in kobject_set_name
> for the kobjet name.
>
> unreferenced object 0xe2167700 (size 64):
> comm "swapper/0", pid 1, jiffies 4294938161 (age 90.540s)
> hex dump (first 32 bytes):
> 6d 61 67 6e 65 74 69 63 00 11 c2 c0 1f e9 23 c1 magnetic......#.
> 18 00 00 00 04 66 9b e4 e0 66 9b e4 94 76 16 e2 .....f...f...v..
> backtrace:
> [<c0fb49dc>] kmemleak_alloc+0x3c/0xa0
> [<c0936cb5>] __kmalloc_track_caller+0x115/0x1d0
> [<c0b6b753>] kvasprintf+0x33/0x60
> [<c0b5fae2>] kobject_set_name_vargs+0x22/0x60
> [<c0b5fb31>] kobject_set_name+0x11/0x20
> [<c0c1f93e>] __class_register+0x8e/0x1e0
> [<c0c1fadb>] __class_create+0x4b/0x70
> [<c1417d61>] mmc3524x_init+0x18/0x97
> [<c080046c>] do_one_initcall+0xbc/0x190
> [<c13e0b47>] kernel_init_freeable+0xea/0x18c
> [<c0fb2fd0>] kernel_init+0x10/0xe0
> [<c0fc3337>] ret_from_kernel_thread+0x1b/0x28
> [<ffffffff>] 0xffffffff
>
> Signed-off-by: Chen Lin Z <[email protected]>
> ---
> drivers/base/class.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/base/class.c b/drivers/base/class.c index
> 6e81088..f6e7f53 100644
> --- a/drivers/base/class.c
> +++ b/drivers/base/class.c
> @@ -200,6 +200,7 @@ int __class_register(struct class *cls, struct
> lock_class_key *key)
>
> error = kset_register(&cp->subsys);
> if (error) {
> + kfree(cp->subsys.kobj.name);
How did you ever trigger this error case?
I don't like mucking about in the root of the kobject name structure, as who
knows what is really happening there. Isn't there some other "better" way to
resolve this?
thanks,
greg k-h
--
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