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[4/5] brcmfmac: Fix race condition in msgbuf ioctl processing.

Message ID 1425663642-19725-5-git-send-email-arend@broadcom.com (mailing list archive)
State Accepted
Delegated to: Kalle Valo
Headers show

Commit Message

Arend van Spriel March 6, 2015, 5:40 p.m. UTC 
From: Hante Meuleman <meuleman@broadcom.com>

Msgbuf is using a wait_event_timeout to wait for the response on
an ioctl. The wakeup routine uses waitqueue_active to see if
wait_event_timeout has been called. There is a chance that the
response arrives before wait_event_timeout is called, this
will result in situation that wait_event_timeout never gets
woken again and assumed result will be a timeout. This patch
removes that errornous situation by always setting the
ctl_completed var before checking for queue active.

Reviewed-by: Arend Van Spriel <arend@broadcom.com>
Reviewed-by: Pieter-Paul Giesberts <pieterpg@broadcom.com>
Signed-off-by: Hante Meuleman <meuleman@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
---
 drivers/net/wireless/brcm80211/brcmfmac/msgbuf.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)
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Patch

diff --git a/drivers/net/wireless/brcm80211/brcmfmac/msgbuf.c b/drivers/net/wireless/brcm80211/brcmfmac/msgbuf.c
index 6262612..4ec9811 100644
--- a/drivers/net/wireless/brcm80211/brcmfmac/msgbuf.c
+++ b/drivers/net/wireless/brcm80211/brcmfmac/msgbuf.c
@@ -481,10 +481,9 @@  static int brcmf_msgbuf_ioctl_resp_wait(struct brcmf_msgbuf *msgbuf)
 
 static void brcmf_msgbuf_ioctl_resp_wake(struct brcmf_msgbuf *msgbuf)
 {
-	if (waitqueue_active(&msgbuf->ioctl_resp_wait)) {
-		msgbuf->ctl_completed = true;
+	msgbuf->ctl_completed = true;
+	if (waitqueue_active(&msgbuf->ioctl_resp_wait))
 		wake_up(&msgbuf->ioctl_resp_wait);
-	}
 }