[PATCH] staging: r8188eu: Use kzalloc() with GFP_ATOMIC in atomic context

[PATCH] staging: r8188eu: Use kzalloc() with GFP_ATOMIC in atomic context

[Fabio M. De Francesco]

Use the GFP_ATOMIC flag of kzalloc() with two memory allocation in
rtw_set_key(). This function is called while holding spinlocks and with
disabled bottom halves, therefore it is not allowed to sleep. With the
GFP_ATOMIC type flag, the allocation is high priority and cannot sleep.

This issue is detected by Smatch which emits the following warning:
drivers/staging/r8188eu/core/rtw_pwrctrl.c:79 ips_leave() warn: sleeping in atomic context
drivers/staging/r8188eu/core/rtw_pwrctrl.c:81 ips_leave() warn: sleeping in atomic context

The calls chain (in reverse order) is the following:

rtw_set_key()
-> ips_leave()
-> -> rtw_pwr_wakeup()
-> -> -> rtw_set_802_11_disassociate()

The disabilitation of bottom halves and the acquisition of a spinlock is in
rtw_set_802_11_disassociate().

After the changes, the post-commit hook output the following messages:

CHECK: Prefer kzalloc(sizeof(*pcmd)...) over kzalloc(sizeof(struct cmd_obj)...)
+       pcmd = kzalloc(sizeof(struct cmd_obj), GFP_ATOMIC);

CHECK: Prefer kzalloc(sizeof(*psetkeyparm)...) over kzalloc(sizeof(struct setkey_parm)...)
+       psetkeyparm = kzalloc(sizeof(struct setkey_parm), GFP_ATOMIC).

According to the above "CHECK[S]", use the preferred style in the first
kzalloc().

Fixes: 79f712ea994d ("staging: r8188eu: Remove wrappers for kalloc() and kzalloc()")
Fixes: 15865124feed ("staging: r8188eu: introduce new core dir for RTL8188eu driver")
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
---
 drivers/staging/r8188eu/core/rtw_mlme.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/r8188eu/core/rtw_mlme.c b/drivers/staging/r8188eu/core/rtw_mlme.c
index 038bddc361c3..860835e29b79 100644
--- a/drivers/staging/r8188eu/core/rtw_mlme.c
+++ b/drivers/staging/r8188eu/core/rtw_mlme.c
@@ -1600,12 +1600,12 @@ int rtw_set_key(struct adapter *adapter, struct security_priv *psecuritypriv, in
 	struct mlme_priv		*pmlmepriv = &adapter->mlmepriv;
 	int	res = _SUCCESS;
 
-	pcmd = kzalloc(sizeof(struct cmd_obj), GFP_KERNEL);
+	pcmd = kzalloc(sizeof(*pcmd), GFP_ATOMIC);
 	if (!pcmd) {
 		res = _FAIL;  /* try again */
 		goto exit;
 	}
-	psetkeyparm = kzalloc(sizeof(struct setkey_parm), GFP_KERNEL);
+	psetkeyparm = kzalloc(sizeof(*psetkeyparm), GFP_ATOMIC);
 	if (!psetkeyparm) {
 		kfree(pcmd);
 		res = _FAIL;
-- 
2.34.1

Re: [PATCH] staging: r8188eu: Use kzalloc() with GFP_ATOMIC in atomic context

[Greg Kroah-Hartman]

On Sun, Feb 06, 2022 at 11:59:43PM +0100, Fabio M. De Francesco wrote:
> Use the GFP_ATOMIC flag of kzalloc() with two memory allocation in
> rtw_set_key(). This function is called while holding spinlocks and with
> disabled bottom halves, therefore it is not allowed to sleep. With the
> GFP_ATOMIC type flag, the allocation is high priority and cannot sleep.
> 
> This issue is detected by Smatch which emits the following warning:
> drivers/staging/r8188eu/core/rtw_pwrctrl.c:79 ips_leave() warn: sleeping in atomic context
> drivers/staging/r8188eu/core/rtw_pwrctrl.c:81 ips_leave() warn: sleeping in atomic context
> 
> The calls chain (in reverse order) is the following:
> 
> rtw_set_key()
> -> ips_leave()
> -> -> rtw_pwr_wakeup()
> -> -> -> rtw_set_802_11_disassociate()
> 
> The disabilitation of bottom halves and the acquisition of a spinlock is in
> rtw_set_802_11_disassociate().
> 
> After the changes, the post-commit hook output the following messages:
> 
> CHECK: Prefer kzalloc(sizeof(*pcmd)...) over kzalloc(sizeof(struct cmd_obj)...)
> +       pcmd = kzalloc(sizeof(struct cmd_obj), GFP_ATOMIC);
> 
> CHECK: Prefer kzalloc(sizeof(*psetkeyparm)...) over kzalloc(sizeof(struct setkey_parm)...)
> +       psetkeyparm = kzalloc(sizeof(struct setkey_parm), GFP_ATOMIC).
> 
> According to the above "CHECK[S]", use the preferred style in the first
> kzalloc().
> 
> Fixes: 79f712ea994d ("staging: r8188eu: Remove wrappers for kalloc() and kzalloc()")
> Fixes: 15865124feed ("staging: r8188eu: introduce new core dir for RTL8188eu driver")
> Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
> ---
>  drivers/staging/r8188eu/core/rtw_mlme.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/staging/r8188eu/core/rtw_mlme.c b/drivers/staging/r8188eu/core/rtw_mlme.c
> index 038bddc361c3..860835e29b79 100644
> --- a/drivers/staging/r8188eu/core/rtw_mlme.c
> +++ b/drivers/staging/r8188eu/core/rtw_mlme.c
> @@ -1600,12 +1600,12 @@ int rtw_set_key(struct adapter *adapter, struct security_priv *psecuritypriv, in
>  	struct mlme_priv		*pmlmepriv = &adapter->mlmepriv;
>  	int	res = _SUCCESS;
>  
> -	pcmd = kzalloc(sizeof(struct cmd_obj), GFP_KERNEL);
> +	pcmd = kzalloc(sizeof(*pcmd), GFP_ATOMIC);
>  	if (!pcmd) {
>  		res = _FAIL;  /* try again */
>  		goto exit;
>  	}
> -	psetkeyparm = kzalloc(sizeof(struct setkey_parm), GFP_KERNEL);
> +	psetkeyparm = kzalloc(sizeof(*psetkeyparm), GFP_ATOMIC);

You are making two different changes here.  Please do the first patch to
change the sizeof() change to fix up checkpatch, and then the second one
for the GFP_ATOMIC change so that if there is a problem with either of
them we can only revert the offending change.

thanks,

greg k-h

Re: [PATCH] staging: r8188eu: Use kzalloc() with GFP_ATOMIC in atomic context

[Fabio M. De Francesco]

On marted? 8 febbraio 2022 10:33:04 CET Greg Kroah-Hartman wrote:
> On Sun, Feb 06, 2022 at 11:59:43PM +0100, Fabio M. De Francesco wrote:
> > Use the GFP_ATOMIC flag of kzalloc() with two memory allocation in
> > rtw_set_key(). This function is called while holding spinlocks and with
> > disabled bottom halves, therefore it is not allowed to sleep. With the
> > GFP_ATOMIC type flag, the allocation is high priority and cannot sleep.
> > 
> > This issue is detected by Smatch which emits the following warning:
> > drivers/staging/r8188eu/core/rtw_pwrctrl.c:79 ips_leave() warn: sleeping in atomic context
> > drivers/staging/r8188eu/core/rtw_pwrctrl.c:81 ips_leave() warn: sleeping in atomic context
> > 
> > The calls chain (in reverse order) is the following:
> > 
> > rtw_set_key()
> > -> ips_leave()
> > -> -> rtw_pwr_wakeup()
> > -> -> -> rtw_set_802_11_disassociate()
> > 
> > The disable of bottom halves and the acquisition of a spinlock is in
> > rtw_set_802_11_disassociate().
> > 
> > After the changes, the post-commit hook output the following messages:
> > 
> > CHECK: Prefer kzalloc(sizeof(*pcmd)...) over kzalloc(sizeof(struct cmd_obj)...)
> > +       pcmd = kzalloc(sizeof(struct cmd_obj), GFP_ATOMIC);
> > 
> > CHECK: Prefer kzalloc(sizeof(*psetkeyparm)...) over kzalloc(sizeof(struct setkey_parm)...)
> > +       psetkeyparm = kzalloc(sizeof(struct setkey_parm), GFP_ATOMIC).
> > 
> > According to the above "CHECK[S]", use the preferred style in the first
> > kzalloc().
> > 
> > Fixes: 79f712ea994d ("staging: r8188eu: Remove wrappers for kalloc() and kzalloc()")
> > Fixes: 15865124feed ("staging: r8188eu: introduce new core dir for RTL8188eu driver")
> > Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
> > ---
> >  drivers/staging/r8188eu/core/rtw_mlme.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> > 
> > [...]
> 
> You are making two different changes here.  Please do the first patch to
> change the sizeof() change to fix up checkpatch, and then the second one
> for the GFP_ATOMIC change so that if there is a problem with either of
> them we can only revert the offending change.
>
OK, thanks for your reply. I'm about to split this patch in two steps as 
you require.

In the while I've noticed that, after git-reset HARD^, Smatch now points directly 
to the kzalloc() calls and emits a different output:

"drivers/staging/r8188eu/core/rtw_mlme.c:1603 rtw_set_key() warn: sleeping in 
atomic context
  CHECK   drivers/staging/r8188eu/core/rtw_mlme_ext.c".

So now it complains specifically about the first of the two kzalloc[s]() in 
rtw_set_key(). Before sending v2, I'd like to check why when I made v1 it pointed 
to the lines that call rtw_set_key(). You'll see that change in the commit message
of v2.

Thanks,

Fabio
>
> thanks,
> 
> greg k-h
> 
> 

[PATCH] staging: r8188eu: Use kzalloc() with GFP_ATOMIC in atomic context

[Fabio M. De Francesco]

Use the GFP_ATOMIC type flag of kzalloc() with two memory allocation in
report_del_sta_event(). This function is called while holding spinlocks,
therefore it is not allowed to sleep. With the GFP_ATOMIC type flag, the
allocation is high priority and must not sleep.

This issue is detected by Smatch which emits the following warning:
"drivers/staging/r8188eu/core/rtw_mlme_ext.c:6848 report_del_sta_event()
warn: sleeping in atomic context".

After the change, the post-commit hook output the following message:
"CHECK: Prefer kzalloc(sizeof(*pcmd_obj)...) over
kzalloc(sizeof(struct cmd_obj)...)".

According to the above "CHECK", use the preferred style in the first
kzalloc().

Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
---
 drivers/staging/r8188eu/core/rtw_mlme_ext.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/r8188eu/core/rtw_mlme_ext.c b/drivers/staging/r8188eu/core/rtw_mlme_ext.c
index 55c3d4a6faeb..3367ec40679d 100644
--- a/drivers/staging/r8188eu/core/rtw_mlme_ext.c
+++ b/drivers/staging/r8188eu/core/rtw_mlme_ext.c
@@ -6845,12 +6845,12 @@ void report_del_sta_event(struct adapter *padapter, unsigned char *MacAddr, unsi
 	struct mlme_ext_priv		*pmlmeext = &padapter->mlmeextpriv;
 	struct cmd_priv *pcmdpriv = &padapter->cmdpriv;
 
-	pcmd_obj = kzalloc(sizeof(struct cmd_obj), GFP_KERNEL);
+	pcmd_obj = kzalloc(*cmd_obj, GFP_ATOMIC);
 	if (!pcmd_obj)
 		return;
 
 	cmdsz = (sizeof(struct stadel_event) + sizeof(struct C2HEvent_Header));
-	pevtcmd = kzalloc(cmdsz, GFP_KERNEL);
+	pevtcmd = kzalloc(cmdsz, GFP_ATOMIC);
 	if (!pevtcmd) {
 		kfree(pcmd_obj);
 		return;
-- 
2.33.1