The patch titled
slab: do not panic when alloc_kmemlist fails and slab is up
has been added to the -mm tree. Its filename is
slab-do-not-panic-when-alloc_kmemlist-fails-and-slab-is-up.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: slab: do not panic when alloc_kmemlist fails and slab is up
From: Christoph Lameter <clameter@xxxxxxx>
It is fairly easy to get a system to oops by simply sizing a cache via
/proc in such a way that one of the chaches (shared is easiest) becomes
bigger than the maximum allowed slab allocation size. This occurs because
enable_cpucache() fails if it cannot reallocate some caches.
However, enable_cpucache() is used for multiple purposes: resizing caches,
cache creation and bootstrap.
If the slab is already up then we already have working caches. The resize
can fail without a problem. We just need to return the proper error code.
F.e. after this patch:
# echo "size-64 10000 50 1000" >/proc/slabinfo
-bash: echo: write error: Cannot allocate memory
notice no OOPS.
If we are doing a kmem_cache_create() then we also should not panic but
return -ENOMEM.
If on the other hand we do not have a fully bootstrapped slab allocator yet
then we should indeed panic since we are unable to bring up the slab to its
full functionality.
Signed-off-by: Christoph Lameter <clameter@xxxxxxx>
Cc: Pekka Enberg <penberg@xxxxxxxxxxxxxx>
Cc: Manfred Spraul <manfred@xxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
mm/slab.c | 35 +++++++++++++++++------------------
1 file changed, 17 insertions(+), 18 deletions(-)
diff -puN mm/slab.c~slab-do-not-panic-when-alloc_kmemlist-fails-and-slab-is-up mm/slab.c
--- a/mm/slab.c~slab-do-not-panic-when-alloc_kmemlist-fails-and-slab-is-up
+++ a/mm/slab.c
@@ -313,7 +313,7 @@ static int drain_freelist(struct kmem_ca
struct kmem_list3 *l3, int tofree);
static void free_block(struct kmem_cache *cachep, void **objpp, int len,
int node);
-static void enable_cpucache(struct kmem_cache *cachep);
+static int enable_cpucache(struct kmem_cache *cachep);
static void cache_reap(void *unused);
/*
@@ -1490,7 +1490,8 @@ void __init kmem_cache_init(void)
struct kmem_cache *cachep;
mutex_lock(&cache_chain_mutex);
list_for_each_entry(cachep, &cache_chain, next)
- enable_cpucache(cachep);
+ if (enable_cpucache(cachep))
+ BUG();
mutex_unlock(&cache_chain_mutex);
}
@@ -1924,12 +1925,11 @@ static size_t calculate_slab_order(struc
return left_over;
}
-static void setup_cpu_cache(struct kmem_cache *cachep)
+static int setup_cpu_cache(struct kmem_cache *cachep)
{
- if (g_cpucache_up == FULL) {
- enable_cpucache(cachep);
- return;
- }
+ if (g_cpucache_up == FULL)
+ return enable_cpucache(cachep);
+
if (g_cpucache_up == NONE) {
/*
* Note: the first kmem_cache_create must create the cache
@@ -1976,6 +1976,7 @@ static void setup_cpu_cache(struct kmem_
cpu_cache_get(cachep)->touched = 0;
cachep->batchcount = 1;
cachep->limit = BOOT_CPUCACHE_ENTRIES;
+ return 0;
}
/**
@@ -2242,8 +2243,11 @@ kmem_cache_create (const char *name, siz
cachep->dtor = dtor;
cachep->name = name;
-
- setup_cpu_cache(cachep);
+ if (setup_cpu_cache(cachep)) {
+ __kmem_cache_destroy(cachep);
+ cachep = NULL;
+ goto oops;
+ }
/* cache setup completed, link it into the list */
list_add(&cachep->next, &cache_chain);
@@ -3693,7 +3697,7 @@ static int do_tune_cpucache(struct kmem_
int batchcount, int shared)
{
struct ccupdate_struct new;
- int i, err;
+ int i;
memset(&new.new, 0, sizeof(new.new));
for_each_online_cpu(i) {
@@ -3724,17 +3728,11 @@ static int do_tune_cpucache(struct kmem_
kfree(ccold);
}
- err = alloc_kmemlist(cachep);
- if (err) {
- printk(KERN_ERR "alloc_kmemlist failed for %s, error %d.\n",
- cachep->name, -err);
- BUG();
- }
- return 0;
+ return alloc_kmemlist(cachep);
}
/* Called with cache_chain_mutex held always */
-static void enable_cpucache(struct kmem_cache *cachep)
+static int enable_cpucache(struct kmem_cache *cachep)
{
int err;
int limit, shared;
@@ -3786,6 +3784,7 @@ static void enable_cpucache(struct kmem_
if (err)
printk(KERN_ERR "enable_cpucache failed for %s, error %d.\n",
cachep->name, -err);
+ return err;
}
/*
_
Patches currently in -mm which might be from clameter@xxxxxxx are
page-migration-replace-radix_tree_lookup_slot-with-radix_tree_lockup.patch
reduce-max_nr_zones-remove-two-strange-uses-of-max_nr_zones.patch
reduce-max_nr_zones-fix-max_nr_zones-array-initializations.patch
reduce-max_nr_zones-make-display-of-highmem-counters-conditional-on-config_highmem.patch
reduce-max_nr_zones-make-display-of-highmem-counters-conditional-on-config_highmem-tidy.patch
reduce-max_nr_zones-move-highmem-counters-into-highmemc-h.patch
reduce-max_nr_zones-move-highmem-counters-into-highmemc-h-fix.patch
reduce-max_nr_zones-page-allocator-zone_highmem-cleanup.patch
reduce-max_nr_zones-use-enum-to-define-zones-reformat-and-comment.patch
reduce-max_nr_zones-use-enum-to-define-zones-reformat-and-comment-cleanup.patch
reduce-max_nr_zones-make-zone_dma32-optional.patch
reduce-max_nr_zones-make-zone_highmem-optional.patch
reduce-max_nr_zones-make-zone_highmem-optional-fix.patch
reduce-max_nr_zones-make-zone_highmem-optional-fix-fix.patch
reduce-max_nr_zones-remove-display-of-counters-for-unconfigured-zones.patch
reduce-max_nr_zones-fix-i386-srat-check-for-max_nr_zones.patch
mempolicies-fix-policy_zone-check.patch
apply-type-enum-zone_type.patch
apply-type-enum-zone_type-fix.patch
linearly-index-zone-node_zonelists.patch
slab-respect-architecture-and-caller-mandated-alignment.patch
slab-optimize-kmalloc_node-the-same-way-as-kmalloc.patch
slab-optimize-kmalloc_node-the-same-way-as-kmalloc-fix.patch
slab-extract-__kmem_cache_destroy-from-kmem_cache_destroy.patch
slab-do-not-panic-when-alloc_kmemlist-fails-and-slab-is-up.patch
add-__gfp_thisnode-to-avoid-fallback-to-other-nodes-and-ignore.patch
sys_move_pages-do-not-fall-back-to-other-nodes.patch
guarantee-that-the-uncached-allocator-gets-pages-on-the-correct.patch
cleanup-add-zone-pointer-to-get_page_from_freelist.patch
x86-implement-always-locked-bit-ops-for-memory-shared-with-an-smp-hypervisor.patch
reduce-max_nr_zones-swap_prefetch-remove-incorrect-use-of-zone_highmem.patch
readahead-state-based-method-aging-accounting-apply-type-enum-zone_type-readahead.patch
-
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