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@xxxxxxxxx>
> ---
> 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
