This is a note to let you know that I've just added the patch titled
mm/slub.c: fix random_seq offset destruction
to the 4.9-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:
mm-slub.c-fix-random_seq-offset-destruction.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From a810007afe239d59c1115fcaa06eb5b480f876e9 Mon Sep 17 00:00:00 2001
From: Sean Rees <sean@xxxxxxxxxx>
Date: Wed, 8 Feb 2017 14:30:59 -0800
Subject: mm/slub.c: fix random_seq offset destruction
From: Sean Rees <sean@xxxxxxxxxx>
commit a810007afe239d59c1115fcaa06eb5b480f876e9 upstream.
Commit 210e7a43fa90 ("mm: SLUB freelist randomization") broke USB hub
initialisation as described in
https://bugzilla.kernel.org/show_bug.cgi?id=177551.
Bail out early from init_cache_random_seq if s->random_seq is already
initialised. This prevents destroying the previously computed
random_seq offsets later in the function.
If the offsets are destroyed, then shuffle_freelist will truncate
page->freelist to just the first object (orphaning the rest).
Fixes: 210e7a43fa90 ("mm: SLUB freelist randomization")
Link: http://lkml.kernel.org/r/20170207140707.20824-1-sean@xxxxxxxxxx
Signed-off-by: Sean Rees <sean@xxxxxxxxxx>
Reported-by: <userwithuid@xxxxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: Pekka Enberg <penberg@xxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Cc: Thomas Garnier <thgarnie@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
mm/slub.c | 4 ++++
1 file changed, 4 insertions(+)
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1419,6 +1419,10 @@ static int init_cache_random_seq(struct
int err;
unsigned long i, count = oo_objects(s->oo);
+ /* Bailout if already initialised */
+ if (s->random_seq)
+ return 0;
+
err = cache_random_seq_create(s, count, GFP_KERNEL);
if (err) {
pr_err("SLUB: Unable to initialize free list for %s\n",
Patches currently in stable-queue which might be from sean@xxxxxxxxxx are
queue-4.9/mm-slub.c-fix-random_seq-offset-destruction.patch
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