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From: "Fabio M. De Francesco" <fmdefrancesco@gmail.com>
To: Larry Finger <Larry.Finger@lwfinger.net>,
	Phillip Potter <phil@philpotter.co.uk>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org
Cc: "Fabio M. De Francesco" <fmdefrancesco@gmail.com>
Subject: [PATCH] staging: r8188eu: Use kzalloc() with GFP_ATOMIC in atomic context
Date: Mon,  1 Nov 2021 12:41:21 +0100	[thread overview]
Message-ID: <20211101114121.23865-1-fmdefrancesco@gmail.com> (raw)

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


             reply	other threads:[~2021-11-01 11:41 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-01 11:41 Fabio M. De Francesco [this message]
2022-02-06 22:59 [PATCH] staging: r8188eu: Use kzalloc() with GFP_ATOMIC in atomic context Fabio M. De Francesco
2022-02-08  9:33 ` Greg Kroah-Hartman
2022-02-08 10:22   ` Fabio M. De Francesco

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