[PATCH] fsi: Aspeed: Fix a potential double free
christophe.jaillet at wanadoo.fr
Mon Dec 27 18:48:38 AEDT 2021
Le 27/12/2021 à 07:29, Greg KH a écrit :
> On Sun, Dec 26, 2021 at 05:56:02PM +0100, Christophe JAILLET wrote:
>> 'aspeed' is a devm_alloc'ed, so there is no need to free it explicitly or
>> there will be a double free().
> A struct device can never be devm_alloced for obvious reasons. Perhaps
> that is the real problem here?
Thanks for the feed-back.
This goes beyond my knowledge of how this should work.
As I can not test myself, I won't be of any help.
I'll let you or anyone else check if something needs to be fixed, and
how to fix it properly.
Just take my patch as a "Hey! Looks strange to have a kfree() in a
driver that only call devm_kzalloc() to allocate memory. S.o. should
give a deeper look at it". :)
>> Remove the 'release' function that is wrong and unneeded.
>> Fixes: 606397d67f41 ("fsi: Add ast2600 master driver")
>> Signed-off-by: Christophe JAILLET <christophe.jaillet at wanadoo.fr>
>> This patch is completely theoretical. It looks good to me, but there is a
>> little too much indirections for me. I'm also not that familiar with
>> fixing issue related to 'release' function...
>> ... So review with care :)
>> drivers/fsi/fsi-master-aspeed.c | 9 ---------
>> 1 file changed, 9 deletions(-)
>> diff --git a/drivers/fsi/fsi-master-aspeed.c b/drivers/fsi/fsi-master-aspeed.c
>> index 8606e55c1721..4a745ccb60cf 100644
>> --- a/drivers/fsi/fsi-master-aspeed.c
>> +++ b/drivers/fsi/fsi-master-aspeed.c
>> @@ -373,14 +373,6 @@ static int aspeed_master_break(struct fsi_master *master, int link)
>> return aspeed_master_write(master, link, 0, addr, &cmd, 4);
>> -static void aspeed_master_release(struct device *dev)
>> - struct fsi_master_aspeed *aspeed =
>> - to_fsi_master_aspeed(dev_to_fsi_master(dev));
>> - kfree(aspeed);
>> /* mmode encoders */
>> static inline u32 fsi_mmode_crs0(u32 x)
>> @@ -603,7 +595,6 @@ static int fsi_master_aspeed_probe(struct platform_device *pdev)
>> dev_info(&pdev->dev, "hub version %08x (%d links)\n", reg, links);
>> aspeed->master.dev.parent = &pdev->dev;
>> - aspeed->master.dev.release = aspeed_master_release;
> Odd, then what deletes this device structure when the release function
> wants to be called? You should have gotten a big warning from the
> kernel when removing the device from the system at runtime, did you test
> this somehow?
> This does not look correct at all.
> greg k-h
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