rtlwifi: Fix scheduling while atomic bug

lwfinger · linvjw · commit a5ffbe0a1993 · 2013-02-04T16:41:56.000-05:00
Kernel commits 41affd5 and 6539306 changed the locking in rtl_lps_leave() from a spinlock to a mutex by doing the calls indirectly from a work queue to reduce the time that interrupts were disabled. This change was fine for most systems; however a scheduling while atomic bug was reported in https://bugzilla.redhat.com/show_bug.cgi?id=903881. The backtrace indicates that routine rtl_is_special(), which calls rtl_lps_leave() in three places was entered in atomic context. These direct calls are replaced by putting a request on the appropriate work queue. Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net> Reported-and-tested-by: Nathaniel Doherty <ntdoherty@gmail.com> Cc: Nathaniel Doherty <ntdoherty@gmail.com> Cc: Stanislaw Gruszka <sgruszka@redhat.com> Cc: Stable <stable@vger.kernel.org> Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/rtlwifi/base.c b/drivers/net/wireless/rtlwifi/base.c
@@ -1004,7 +1004,8 @@ u8 rtl_is_special_data(struct ieee80211_hw *hw, struct sk_buff *skb, u8 is_tx)
 					 is_tx ? "Tx" : "Rx");
 
 				if (is_tx) {
-					rtl_lps_leave(hw);
+					schedule_work(&rtlpriv->
+						      works.lps_leave_work);
 					ppsc->last_delaylps_stamp_jiffies =
 					    jiffies;
 				}
@@ -1014,7 +1015,7 @@ u8 rtl_is_special_data(struct ieee80211_hw *hw, struct sk_buff *skb, u8 is_tx)
 		}
 	} else if (ETH_P_ARP == ether_type) {
 		if (is_tx) {
-			rtl_lps_leave(hw);
+			schedule_work(&rtlpriv->works.lps_leave_work);
 			ppsc->last_delaylps_stamp_jiffies = jiffies;
 		}
 
@@ -1024,7 +1025,7 @@ u8 rtl_is_special_data(struct ieee80211_hw *hw, struct sk_buff *skb, u8 is_tx)
 			 "802.1X %s EAPOL pkt!!\n", is_tx ? "Tx" : "Rx");
 
 		if (is_tx) {
-			rtl_lps_leave(hw);
+			schedule_work(&rtlpriv->works.lps_leave_work);
 			ppsc->last_delaylps_stamp_jiffies = jiffies;
 		}
 

Original file line number	Diff line number	Diff line change
`@@ -1004,7 +1004,8 @@ u8 rtl_is_special_data(struct ieee80211_hw hw, struct sk_buff skb, u8 is_tx)`
`1004`	`1004`	`is_tx ? "Tx" : "Rx");`
`1005`	`1005`
`1006`	`1006`	`if (is_tx) {`
`1007`		`- rtl_lps_leave(hw);`
	`1007`	`+ schedule_work(&rtlpriv->`
	`1008`	`+ works.lps_leave_work);`
`1008`	`1009`	`ppsc->last_delaylps_stamp_jiffies =`
`1009`	`1010`	`jiffies;`
`1010`	`1011`	`}`
`@@ -1014,7 +1015,7 @@ u8 rtl_is_special_data(struct ieee80211_hw hw, struct sk_buff skb, u8 is_tx)`
`1014`	`1015`	`}`
`1015`	`1016`	`} else if (ETH_P_ARP == ether_type) {`
`1016`	`1017`	`if (is_tx) {`
`1017`		`- rtl_lps_leave(hw);`
	`1018`	`+ schedule_work(&rtlpriv->works.lps_leave_work);`
`1018`	`1019`	`ppsc->last_delaylps_stamp_jiffies = jiffies;`
`1019`	`1020`	`}`
`1020`	`1021`
`@@ -1024,7 +1025,7 @@ u8 rtl_is_special_data(struct ieee80211_hw hw, struct sk_buff skb, u8 is_tx)`
`1024`	`1025`	`"802.1X %s EAPOL pkt!!\n", is_tx ? "Tx" : "Rx");`
`1025`	`1026`
`1026`	`1027`	`if (is_tx) {`
`1027`		`- rtl_lps_leave(hw);`
	`1028`	`+ schedule_work(&rtlpriv->works.lps_leave_work);`
`1028`	`1029`	`ppsc->last_delaylps_stamp_jiffies = jiffies;`
`1029`	`1030`	`}`
`1030`	`1031`