Patch "cxl: Keep IRQ mappings on context teardown" has been added to the 4.4-stable tree

This is a note to let you know that I've just added the patch titled

cxl: Keep IRQ mappings on context teardown

to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
cxl-keep-irq-mappings-on-context-teardown.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Michael Neuling <[email protected]>
Date: Fri, 22 Apr 2016 14:57:48 +1000
Subject: cxl: Keep IRQ mappings on context teardown

From: Michael Neuling <[email protected]>

commit d6776bba44d9752f6cdf640046070e71ee4bba7b upstream.

Keep IRQ mappings on context teardown. This won't leak IRQs as if we allocate the mapping again, the generic code will give the same mapping used last time.

Doing this works around a race in the generic code. Masking the interrupt introduces a race which can crash the kernel or result in IRQ that is never EOIed. The lost of EOI results in all subsequent mappings to the same HW IRQ never receiving an interrupt.

We've seen this race with cxl test cases which are doing heavy context startup and teardown at the same time as heavy interrupt load.

A fix to the generic code is being investigated also.

---
 drivers/misc/cxl/irq.c |    1 -
 1 file changed, 1 deletion(-)

@@ -288,7 +288,6 @@ unsigned int cxl_map_irq(struct cxl *ada
 void cxl_unmap_irq(unsigned int virq, void *cookie)
 {
 	free_irq(virq, cookie);
-	irq_dispose_mapping(virq);
 }
 
 static int cxl_register_one_irq(struct cxl *adapter,

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/cxl-keep-irq-mappings-on-context-teardown.patch