[3.13.y.z extended stable] Patch "percpu: perform tlb flush after pcpu_map_pages() failure" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    percpu: perform tlb flush after pcpu_map_pages() failure

to the linux-3.13.y-queue branch of the 3.13.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.13.y-queue

This patch is scheduled to be released in version 3.13.11.9.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.13.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 7f6d593bf377945bdd44d0d6c72d1e8fad9dc65c Mon Sep 17 00:00:00 2001
From: Tejun Heo <tj at kernel.org>
Date: Fri, 15 Aug 2014 16:06:10 -0400
Subject: percpu: perform tlb flush after pcpu_map_pages() failure

commit 849f5169097e1ba35b90ac9df76b5bb6f9c0aabd upstream.

If pcpu_map_pages() fails midway, it unmaps the already mapped pages.
Currently, it doesn't flush tlb after the partial unmapping.  This may
be okay in most cases as the established mapping hasn't been used at
that point but it can go wrong and when it goes wrong it'd be
extremely difficult to track down.

Flush tlb after the partial unmapping.

Signed-off-by: Tejun Heo <tj at kernel.org>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 mm/percpu-vm.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/mm/percpu-vm.c b/mm/percpu-vm.c
index 8d9bb2c..5110816 100644
--- a/mm/percpu-vm.c
+++ b/mm/percpu-vm.c
@@ -272,6 +272,7 @@ err:
 		__pcpu_unmap_pages(pcpu_chunk_addr(chunk, tcpu, page_start),
 				   page_end - page_start);
 	}
+	pcpu_post_unmap_tlb_flush(chunk, page_start, page_end);
 	return err;
 }

--
1.9.1