Bug 58662 - Fix for aacraid interrupt flood
Fix for aacraid interrupt flood
Product: Red Hat Linux
Classification: Retired
Component: kernel (Show other bugs)
i386 Linux
medium Severity high
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Assigned To: Arjan van de Ven
Brian Brock
Depends On:
  Show dependency treegraph
Reported: 2002-01-22 10:24 EST by Matt Domsch
Modified: 2007-04-18 12:39 EDT (History)
0 users

See Also:
Fixed In Version:
Doc Type: Bug Fix
Doc Text:
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Clone Of:
Last Closed: 2002-01-22 10:25:04 EST
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RHEL 7.3 requirements from Atomic Host:
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Description Matt Domsch 2002-01-22 10:24:59 EST
Description of Problem:
From: Chris Pascoe [mailto:c.pascoe@itee.uq.edu.au]
Sent: Tuesday, January 22, 2002 6:58 AM

Hi Alan,

The problem with millions of interrupts being generated by the aacraid
driver on some hardware is caused by reversed arguments to time_before in
rx_sync_cmd.  This causes every synchronous command sent to the controller
to miss acknowledgement, including our one to start the adapter.  When
interrupts are subsequently re-enabled, we get a continuous stream of
interrupts as the command has actually completed, and there is no path in
aac_rx_intr to acknowledge the command.

The following patch corrects the described problem.

--- linux/drivers/scsi/aacraid/rx.c.orig	Tue Jan 22 22:40:58 2002
+++ linux/drivers/scsi/aacraid/rx.c	Tue Jan 22 22:41:19 2002
@@ -199,7 +199,7 @@
 	 *	Wait up to 30 seconds
-	while (time_before(start+30*HZ, jiffies))
+	while (time_before(jiffies, start+30*HZ))
 		udelay(5);	/* Delay 5 microseconds to let Mon960 get info. 


Version-Release number of selected component (if applicable):
~ 2.4.9-20 kernel, stock kernel 2.4.17 through 2.4.18-pre4 at least.

How Reproducible:
Always on systems with i960 embedded RAID and aacraid driver.

Steps to Reproduce:
1. start aacraid driver

Actual Results:
150,000 interrupts/second or more, even with no disk activity.

Expected Results:
a very very small number of interrupts per second

Additional Information:
Comment 1 Arjan van de Ven 2002-02-11 13:02:48 EST
added to the relevant trees a while ago.

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