netdev - [net-next 09/12] bna: MBOX IRQ Flag Check after Locking

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <1314754068-31978-10-git-send-email-rmody@brocade.com>
Date:	Tue, 30 Aug 2011 18:27:45 -0700
From:	Rasesh Mody <rmody@...cade.com>
To:	<davem@...emloft.net>, <netdev@...r.kernel.org>
CC:	<adapter_linux_open_src_team@...cade.com>,
	Rasesh Mody <rmody@...cade.com>,
	Gurunatha Karaje <gkaraje@...cade.com>
Subject: [net-next 09/12] bna: MBOX IRQ Flag Check after Locking

Change details:
 - Check the BNAD_RF_MBOX_IRQ_DISABLED flag after acquiring the bna_lock,
   since checking the flag and executing bna_mbox_handler needs to be atomic.
   If not, it opens up window where flag is reset when it was checked, but got
   set while spinning on the lock by the other thread which is actually
   holding the lock

Signed-off-by: Gurunatha Karaje <gkaraje@...cade.com>
Signed-off-by: Rasesh Mody <rmody@...cade.com>
---
 drivers/net/ethernet/brocade/bna/bnad.c |   18 +++++++++++-------
 1 files changed, 11 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ethernet/brocade/bna/bnad.c b/drivers/net/ethernet/brocade/bna/bnad.c
index 0202b98..c6313e8 100644
--- a/drivers/net/ethernet/brocade/bna/bnad.c
+++ b/drivers/net/ethernet/brocade/bna/bnad.c
@@ -586,10 +586,11 @@ bnad_msix_mbox_handler(int irq, void *data)
 	unsigned long flags;
 	struct bnad *bnad = (struct bnad *)data;
 
-	if (unlikely(test_bit(BNAD_RF_MBOX_IRQ_DISABLED, &bnad->run_flags)))
-		return IRQ_HANDLED;
-
 	spin_lock_irqsave(&bnad->bna_lock, flags);
+	if (unlikely(test_bit(BNAD_RF_MBOX_IRQ_DISABLED, &bnad->run_flags))) {
+		spin_unlock_irqrestore(&bnad->bna_lock, flags);
+		return IRQ_HANDLED;
+	}
 
 	bna_intr_status_get(&bnad->bna, intr_status);
 
@@ -612,15 +613,18 @@ bnad_isr(int irq, void *data)
 	struct bnad_rx_ctrl *rx_ctrl;
 	struct bna_tcb *tcb = NULL;
 
-	if (unlikely(test_bit(BNAD_RF_MBOX_IRQ_DISABLED, &bnad->run_flags)))
+	spin_lock_irqsave(&bnad->bna_lock, flags);
+	if (unlikely(test_bit(BNAD_RF_MBOX_IRQ_DISABLED, &bnad->run_flags))) {
+		spin_unlock_irqrestore(&bnad->bna_lock, flags);
 		return IRQ_NONE;
+	}
 
 	bna_intr_status_get(&bnad->bna, intr_status);
 
-	if (unlikely(!intr_status))
+	if (unlikely(!intr_status)) {
+		spin_unlock_irqrestore(&bnad->bna_lock, flags);
 		return IRQ_NONE;
-
-	spin_lock_irqsave(&bnad->bna_lock, flags);
+	}
 
 	if (BNA_IS_MBOX_ERR_INTR(&bnad->bna, intr_status))
 		bna_mbox_handler(&bnad->bna, intr_status);
-- 
1.7.1

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html