From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        "Fabio M. De Francesco" <fmdefrancesco@gmail.com>
Subject: [PATCH 5.15 031/179] staging: r8188eu: Use kzalloc() with GFP_ATOMIC in atomic context
Date:   Mon, 29 Nov 2021 19:17:05 +0100
Message-Id: <20211129181719.975204668@linuxfoundation.org>
In-Reply-To: <20211129181718.913038547@linuxfoundation.org>
References: <20211129181718.913038547@linuxfoundation.org>
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From: Fabio M. De Francesco <fmdefrancesco@gmail.com>

commit c15a059f85de49c542e6ec2464967dd2b2aa18f6 upstream.

Use the GFP_ATOMIC 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().

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>
Link: https://lore.kernel.org/r/20211101191847.6749-1-fmdefrancesco@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: stable <stable@vger.kernel.org>
---
 drivers/staging/r8188eu/core/rtw_mlme_ext.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/staging/r8188eu/core/rtw_mlme_ext.c
+++ b/drivers/staging/r8188eu/core/rtw_mlme_ext.c
@@ -7080,12 +7080,12 @@ void report_del_sta_event(struct adapter
 	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(sizeof(*pcmd_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;