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* [PATCH v1] net: dev: Use unsigned integer as an argument to left-shift
@ 2019-02-27 10:37 Andy Shevchenko
  2019-02-27 17:34 ` David Miller
  0 siblings, 1 reply; 2+ messages in thread
From: Andy Shevchenko @ 2019-02-27 10:37 UTC (permalink / raw)
  To: David S. Miller, netdev; +Cc: Andy Shevchenko

1 << 31 is Undefined Behaviour according to the C standard.
Use U type modifier to avoid theoretical overflow.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 include/linux/netdevice.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 86dbb3e29139..848b54b7ec91 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -3861,7 +3861,7 @@ static inline u32 netif_msg_init(int debug_value, int default_msg_enable_bits)
 	if (debug_value == 0)	/* no output */
 		return 0;
 	/* set low N bits */
-	return (1 << debug_value) - 1;
+	return (1U << debug_value) - 1;
 }
 
 static inline void __netif_tx_lock(struct netdev_queue *txq, int cpu)
-- 
2.20.1


^ permalink raw reply related	[flat|nested] 2+ messages in thread

* Re: [PATCH v1] net: dev: Use unsigned integer as an argument to left-shift
  2019-02-27 10:37 [PATCH v1] net: dev: Use unsigned integer as an argument to left-shift Andy Shevchenko
@ 2019-02-27 17:34 ` David Miller
  0 siblings, 0 replies; 2+ messages in thread
From: David Miller @ 2019-02-27 17:34 UTC (permalink / raw)
  To: andriy.shevchenko; +Cc: netdev

From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Date: Wed, 27 Feb 2019 13:37:26 +0300

> 1 << 31 is Undefined Behaviour according to the C standard.
> Use U type modifier to avoid theoretical overflow.
> 
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

Applied, thanks Andy.

^ permalink raw reply	[flat|nested] 2+ messages in thread

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