Re: [PATCH 05/10] wifi: ath12k: fix SLUB BUG - Object already free in ath12k_reg_free()

[Aditya Kumar Singh]

On 1/14/25 00:51, Jeff Johnson wrote:
> > diff --git a/drivers/net/wireless/ath/ath12k/reg.c b/drivers/net/wireless/ath/ath12k/reg.c
> > index 439d61f284d89222e79c05d6cff8e85d0d315aad..b4d7fa1a04ca0e72728e8989c29b82d089171fc2 100644
> > --- a/drivers/net/wireless/ath/ath12k/reg.c
> > +++ b/drivers/net/wireless/ath/ath12k/reg.c
> > @@ -1,7 +1,7 @@
> >   // SPDX-License-Identifier: BSD-3-Clause-Clear
> >   /*
> >    * Copyright (c) 2018-2021 The Linux Foundation. All rights reserved.
> > - * Copyright (c) 2021-2024 Qualcomm Innovation Center, Inc. All rights reserved.
> > + * Copyright (c) 2021-2025 Qualcomm Innovation Center, Inc. All rights reserved.
> >    */
> >   #include <linux/rtnetlink.h>
> >   #include "core.h"
> > @@ -777,8 +777,14 @@ void ath12k_reg_free(struct ath12k_base *ab)
> >   {
> >   	int i;
> >   
> > +	if (ab->regd_freed)
> > +		return;
> > +
> >   	for (i = 0; i < ab->hw_params->max_radios; i++) {
> >   		kfree(ab->default_regd[i]);
> >   		kfree(ab->new_regd[i]);
> > +		ab->default_regd[i] = NULL;
> > +		ab->new_regd[i] = NULL;
> > +		ab->regd_freed = true;
> since it is loop invariant, should this last assignment be outside the loop,
> either before or after the loop?
>
> but then again, why is a flag needed since setting the pointers to NULL should
> already show they are freed, and any race conditions with those pointers would
> also exist with the new flag (which you have addressed with the locking change).

Well, looks like, this flag is not needed. I will remove this in next 
version. Thanks for pointing it out!

--
Aditya