Patch "rhashtable: fix for resize events during table walk" has been added to the 4.1-stable tree

Patch "rhashtable: fix for resize events during table walk" has been added to the 4.1-stable tree

[gregkh]

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

    rhashtable: fix for resize events during table walk

to the 4.1-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:
     rhashtable-fix-for-resize-events-during-table-walk.patch
and it can be found in the queue-4.1 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From foo@baz Sat Sep 26 11:13:07 PDT 2015
From: Phil Sutter <phil@nwl.cc>
Date: Mon, 6 Jul 2015 15:51:20 +0200
Subject: rhashtable: fix for resize events during table walk

From: Phil Sutter <phil@nwl.cc>

[ Upstream commit 142b942a75cb10ede1b42bf85368d41449ab4e3b ]

If rhashtable_walk_next detects a resize operation in progress, it jumps
to the new table and continues walking that one. But it misses to drop
the reference to it's current item, leading it to continue traversing
the new table's bucket in which the current item is sorted into, and
after reaching that bucket's end continues traversing the new table's
second bucket instead of the first one, thereby potentially missing
items.

This fixes the rhashtable runtime test for me. Bug probably introduced
by Herbert Xu's patch eddee5ba ("rhashtable: Fix walker behaviour during
rehash") although not explicitly tested.

Fixes: eddee5ba ("rhashtable: Fix walker behaviour during rehash")
Signed-off-by: Phil Sutter <phil@nwl.cc>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 lib/rhashtable.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/lib/rhashtable.c
+++ b/lib/rhashtable.c
@@ -612,6 +612,8 @@ next:
 		iter->skip = 0;
 	}
 
+	iter->p = NULL;
+
 	/* Ensure we see any new tables. */
 	smp_rmb();
 
@@ -622,8 +624,6 @@ next:
 		return ERR_PTR(-EAGAIN);
 	}
 
-	iter->p = NULL;
-
 out:
 
 	return obj;


Patches currently in stable-queue which might be from phil@nwl.cc are

queue-4.1/rhashtable-fix-for-resize-events-during-table-walk.patch