linux-kernel - [PATCH] rtl8188eu: Fix a possible sleep-in-atomic bug in set_tx_beacon

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Date:   Tue, 12 Dec 2017 21:08:06 +0800
From:   Jia-Ju Bai <baijiaju1990@...il.com>
To:     gregkh@...uxfoundation.org, aishpant@...il.com,
        insafonov@...il.com, luca@...aceresoli.net, goudapatilk@...il.com,
        armetallica@...il.com, keescook@...omium.org,
        mihaela.muraru21@...il.com
Cc:     devel@...verdev.osuosl.org, linux-kernel@...r.kernel.org,
        Jia-Ju Bai <baijiaju1990@...il.com>
Subject: [PATCH] rtl8188eu: Fix a possible sleep-in-atomic bug in set_tx_beacon_cmd

The driver may sleep under a spinlock.
The function call path is:
update_beacon (acquire the spinlock)
  update_BCNTIM
    set_tx_beacon_cmd
      kzalloc(GFP_KERNEL) --> may sleep
      kmemdup(GFP_KERNEL) --> may sleep

To fix it, GFP_KERNEL is replaced with GFP_ATOMIC.

This bug is found by my static analysis tool(DSAC) and checked by my code review.

Signed-off-by: Jia-Ju Bai <baijiaju1990@...il.com>
---
 drivers/staging/rtl8188eu/core/rtw_mlme_ext.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/rtl8188eu/core/rtw_mlme_ext.c b/drivers/staging/rtl8188eu/core/rtw_mlme_ext.c
index d73e9bd..bcb6919 100644
--- a/drivers/staging/rtl8188eu/core/rtw_mlme_ext.c
+++ b/drivers/staging/rtl8188eu/core/rtw_mlme_ext.c
@@ -5395,14 +5395,14 @@ u8 set_tx_beacon_cmd(struct adapter *padapter)
 	int len_diff = 0;
 
 
-	ph2c = kzalloc(sizeof(struct cmd_obj), GFP_KERNEL);
+	ph2c = kzalloc(sizeof(struct cmd_obj), GFP_ATOMIC);
 	if (!ph2c) {
 		res = _FAIL;
 		goto exit;
 	}
 
 	ptxBeacon_parm = kmemdup(&(pmlmeinfo->network),
-				sizeof(struct wlan_bssid_ex), GFP_KERNEL);
+				sizeof(struct wlan_bssid_ex), GFP_ATOMIC);
 	if (ptxBeacon_parm == NULL) {
 		kfree(ph2c);
 		res = _FAIL;
-- 
1.7.9.5