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From: Stefani Seibold <stefani@seibold.net>
To: linux-kernel <linux-kernel@vger.kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Subject: [tip:urgent] fix kfifo_out_locked race bug
Date: Tue, 05 Jan 2010 14:38:35 +0100	[thread overview]
Message-ID: <1262698715.4532.7.camel@wall-e> (raw)
In-Reply-To: <1262692881.23577.15.camel@wall-e>

This patch fix a wrong optimization in include/linux/kfifo.h which could
cause a race in kfifo_out_locked.

Please apply it to the 2.6.33-rc* tree.

Signed-off-by: Stefani Seibold <stefani@seibold.net>
---
 kfifo.h |    7 -------
 1 file changed, 7 deletions(-)

--- linux-2.6.33-rc2.orig/include/linux/kfifo.h	2009-12-27
23:37:04.921185257 +0100
+++ kfifo.h	2010-01-05 14:32:31.414316321 +0100
@@ -228,13 +228,6 @@ static inline __must_check unsigned int 
 
 	ret = kfifo_out(fifo, to, n);
 
-	/*
-	 * optimization: if the FIFO is empty, set the indices to 0
-	 * so we don't wrap the next time
-	 */
-	if (kfifo_is_empty(fifo))
-		kfifo_reset(fifo);
-
 	spin_unlock_irqrestore(lock, flags);
 
 	return ret;



  parent reply	other threads:[~2010-01-05 13:38 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-01-04 17:43 USB: serial: kfifo_len locking Johan Hovold
2010-01-04 19:20 ` Stefani Seibold
2010-01-05  7:43   ` Pete Zaitcev
2010-01-05  7:51     ` Stefani Seibold
2010-01-05 11:04     ` Johan Hovold
2010-01-05 11:09       ` Stefani Seibold
2010-01-05 11:14         ` Johan Hovold
2010-01-05 11:25           ` Stefani Seibold
2010-01-05 11:35             ` Johan Hovold
2010-01-05 12:01               ` Stefani Seibold
2010-01-05 12:10                 ` Johan Hovold
2010-01-05 13:30                 ` [tip:urgent] fix USB serial fix " Stefani Seibold
2010-01-05 14:32                   ` Greg KH
2010-01-05 13:38                 ` Stefani Seibold [this message]
2010-01-08 23:18                   ` [tip:urgent] fix kfifo_out_locked race bug Andrew Morton
2010-01-05 17:00         ` USB: serial: kfifo_len locking Pete Zaitcev

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