Messages in this thread | | | Subject | Re: [PATCH 2/2 v2] mtd: ubi: use put_device() if device_register fail | From | arvindY <> | Date | Thu, 15 Mar 2018 23:11:58 +0530 |
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On Thursday 15 March 2018 02:17 PM, Arvind Yadav wrote: > > > On Thursday 15 March 2018 01:25 PM, Richard Weinberger wrote: >> Am Donnerstag, 15. März 2018, 08:20:31 CET schrieb Arvind Yadav: >>> if device_register() returned an error! Always use put_device() >>> to give up the reference initialized. >> Like DaveM said, there is no need to shout and use "!". > > I will fix this and send you update patch. >>> Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com> >>> --- >>> change in v2: >>> Fix use-after-free bug. move put_device() after cdev_del(). >>> >>> drivers/mtd/ubi/vmt.c | 1 + >>> 1 file changed, 1 insertion(+) >>> >>> diff --git a/drivers/mtd/ubi/vmt.c b/drivers/mtd/ubi/vmt.c >>> index 3fd8d7f..93c6163 100644 >>> --- a/drivers/mtd/ubi/vmt.c >>> +++ b/drivers/mtd/ubi/vmt.c >>> @@ -610,6 +610,7 @@ int ubi_add_volume(struct ubi_device *ubi, struct >>> ubi_volume *vol) >>> >>> out_cdev: >>> cdev_del(&vol->cdev); >>> + put_device(&vol->dev); >>> return err; >> The more I dig into device code, the more questions I have. >> Why is cdev_del() not part of the release function? >> >> Thanks, >> //richard > > Yes, It's should be a part release function. > > ~arvind
I was wrong, We can not add cdev_del() in release(vol_release) function. Function's ubi_create_volume and ubi_add_volume both are using same release function to release a volume devices. ubi_add_volume is registering character device for the volume. So we will have to release character device here.
~arvind
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