[to-be-updated] slub-fix-__kmem_cache_empty-for-config_slub_debug.patch removed from -mm tree

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



The patch titled
     Subject: slub: fix __kmem_cache_empty for !CONFIG_SLUB_DEBUG
has been removed from the -mm tree.  Its filename was
     slub-fix-__kmem_cache_empty-for-config_slub_debug.patch

This patch was dropped because an updated version will be merged

------------------------------------------------------
From: Shakeel Butt <shakeelb@xxxxxxxxxx>
Subject: slub: fix __kmem_cache_empty for !CONFIG_SLUB_DEBUG

f9e13c0a5a33 ("slab, slub: skip unnecessary kasan_cache_shutdown()")
causes crashes when using slub, as described at
http://lkml.kernel.org/r/CAHmME9rtoPwxUSnktxzKso14iuVCWT7BE_-_8PAC=pGw1iJnQg@xxxxxxxxxxxxxx

For !CONFIG_SLUB_DEBUG, SLUB does not maintain the number of slabs
allocated per node for a kmem_cache.  Thus, slabs_node() in
__kmem_cache_empty() will always return 0.  So, in such situation, it is
required to check per-cpu slabs to make sure if a kmem_cache is empty or
not.

Please note that __kmem_cache_shutdown() and __kmem_cache_shrink() are not
affected by !CONFIG_SLUB_DEBUG as they call flush_all() to clear per-cpu
slabs.

Link: http://lkml.kernel.org/r/20180619213352.71740-1-shakeelb@xxxxxxxxxx
Link: http://lkml.kernel.org/r/CAHmME9rtoPwxUSnktxzKso14iuVCWT7BE_-_8PAC=pGw1iJnQg@xxxxxxxxxxxxxx
Fixes: f9e13c0a5a33 ("slab, slub: skip unnecessary kasan_cache_shutdown()")
Signed-off-by: Shakeel Butt <shakeelb@xxxxxxxxxx>
Reported-by: Jason A. Donenfeld <Jason@xxxxxxxxx>
Tested-by: Jason A. Donenfeld <Jason@xxxxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: Pekka Enberg <penberg@xxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---

 mm/slub.c |   16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff -puN mm/slub.c~slub-fix-__kmem_cache_empty-for-config_slub_debug mm/slub.c
--- a/mm/slub.c~slub-fix-__kmem_cache_empty-for-config_slub_debug
+++ a/mm/slub.c
@@ -3673,9 +3673,23 @@ static void free_partial(struct kmem_cac
 
 bool __kmem_cache_empty(struct kmem_cache *s)
 {
-	int node;
+	int cpu, node;
 	struct kmem_cache_node *n;
 
+	/*
+	 * slabs_node will always be 0 for !CONFIG_SLUB_DEBUG. So, manually
+	 * check slabs for all cpus.
+	 */
+	if (!IS_ENABLED(CONFIG_SLUB_DEBUG)) {
+		for_each_online_cpu(cpu) {
+			struct kmem_cache_cpu *c;
+
+			c = per_cpu_ptr(s->cpu_slab, cpu);
+			if (c->page || slub_percpu_partial(c))
+				return false;
+		}
+	}
+
 	for_each_kmem_cache_node(s, node, n)
 		if (n->nr_partial || slabs_node(s, node))
 			return false;
_

Patches currently in -mm which might be from shakeelb@xxxxxxxxxx are

slub-track-number-of-slabs-irrespective-of-config_slub_debug.patch




[Index of Archives]     [Linux Kernel]     [Kernel Development Newbies]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite Hiking]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux