Re: [PATCH v2 2/2] staging: r8188eu: Use kzalloc() with GFP_ATOMIC in atomic context

Greg Kroah-Hartman
2022-02-15T16:10:25Z

On Tue, Feb 08, 2022 at 07:04:26PM +0100, Fabio M. De Francesco wrote:
> Use the GFP_ATOMIC flag of kzalloc() with two memory allocation in rtw_set_key()
> because it is not allowed to sleep while it executes in atomic context.
>
> With the GFP_ATOMIC type flag, the allocation is high priority and thus it
> cannot sleep.
>
> This issue is detected by Smatch which emits the following warning:
>
> "drivers/staging/r8188eu/core/rtw_mlme.c:1603 rtw_set_key() warn: sleeping in atomic context".
>
> 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 f5b2df72e0f4..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(*pcmd), GFP_KERNEL);
> + pcmd = kzalloc(sizeof(*pcmd), GFP_ATOMIC);
> if (!pcmd) {
> res = _FAIL; /* try again */
> goto exit;
> }
> - psetkeyparm = kzalloc(sizeof(*psetkeyparm), GFP_KERNEL);
> + psetkeyparm = kzalloc(sizeof(*psetkeyparm), GFP_ATOMIC);
> if (!psetkeyparm) {
> kfree(pcmd);
> res = _FAIL;
> --
> 2.34.1

What code path is calling this in atomic context?

thanks,

greg k-h