From 4f101c47791cdcb831b3ef1f831b1cc51e4fe03c Mon Sep 17 00:00:00 2001 From: Florian Fainelli Date: Wed, 24 Aug 2016 11:01:20 -0700 Subject: [PATCH] net: dsa: bcm_sf2: Fix race condition while unmasking interrupts We kept shadow copies of which interrupt sources we have enabled and disabled, but due to an order bug in how intrl2_mask_clear was defined, we could run into the following scenario: CPU0 CPU1 intrl2_1_mask_clear(..) sets INTRL2_CPU_MASK_CLEAR bcm_sf2_switch_1_isr read INTRL2_CPU_STATUS and masks with stale irq1_mask value updates irq1_mask value Which would make us loop again and again trying to process and interrupt we are not clearing since our copy of whether it was enabled before still indicates it was not. Fix this by updating the shadow copy first, and then unasking at the HW level. Fixes: 246d7f773c13 ("net: dsa: add Broadcom SF2 switch driver") Signed-off-by: Florian Fainelli Signed-off-by: David S. Miller --- drivers/net/dsa/bcm_sf2.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/dsa/bcm_sf2.h b/drivers/net/dsa/bcm_sf2.h index 463bed8cbe4c..dd446e466699 100644 --- a/drivers/net/dsa/bcm_sf2.h +++ b/drivers/net/dsa/bcm_sf2.h @@ -205,8 +205,8 @@ static inline void name##_writeq(struct bcm_sf2_priv *priv, u64 val, \ static inline void intrl2_##which##_mask_clear(struct bcm_sf2_priv *priv, \ u32 mask) \ { \ - intrl2_##which##_writel(priv, mask, INTRL2_CPU_MASK_CLEAR); \ priv->irq##which##_mask &= ~(mask); \ + intrl2_##which##_writel(priv, mask, INTRL2_CPU_MASK_CLEAR); \ } \ static inline void intrl2_##which##_mask_set(struct bcm_sf2_priv *priv, \ u32 mask) \ -- 2.39.5