The patch titled
slab: do not panic when alloc_kmemlist fails and slab is up
has been removed from the -mm tree. Its filename is
slab-do-not-panic-when-alloc_kmemlist-fails-and-slab-is-up.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
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
origin.patch
git-ia64.patch
slab-fix-kmalloc_node-applying-memory-policies-if-nodeid-==-numa_node_id.patch
add-numa_build-definition-in-kernelh-to-avoid-ifdef.patch
disable-gfp_thisnode-in-the-non-numa-case.patch
gfp_thisnode-for-the-slab-allocator-v2.patch
gfp_thisnode-for-the-slab-allocator-v2-fix-3.patch
add-node-to-zone-for-the-numa-case.patch
add-node-to-zone-for-the-numa-case-fix.patch
get-rid-of-zone_table.patch
get-rid-of-zone_table-fix.patch
do-not-allocate-pagesets-for-unpopulated-zones.patch
zone_statistics-use-hot-node-instead-of-cold-zone_pgdat.patch
deal-with-cases-of-zone_dma-meaning-the-first-zone.patch
introduce-config_zone_dma.patch
optional-zone_dma-in-the-vm.patch
optional-zone_dma-for-i386.patch
optional-zone_dma-for-x86_64.patch
optional-zone_dma-for-ia64.patch
remove-zone_dma-remains-from-parisc.patch
remove-zone_dma-remains-from-sh-sh64.patch
radix-tree-rcu-lockless-readside.patch
scheduler-numa-aware-placement-of-sched_group_allnodes.patch
zvc-support-nr_slab_reclaimable--nr_slab_unreclaimable-swap_prefetch.patch
reduce-max_nr_zones-swap_prefetch-remove-incorrect-use-of-zone_highmem.patch
numa-add-zone_to_nid-function-swap_prefetch.patch
readahead-state-based-method-aging-accounting-apply-type-enum-zone_type-readahead.patch
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