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authorChristoph Lameter <clameter@sgi.com>2006-09-25 23:31:38 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-09-26 08:48:50 -0700
commit2ed3a4ef95ef1a13a424378c34ebd9b7e593f212 (patch)
treebb08e0b3526ab71639197fad649349dc222e0451
parent117f6eb1d8b8deb6f19fc88fc15bdb413c2a0c79 (diff)
[PATCH] slab: do not panic when alloc_kmemlist fails and slab is up
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@sgi.com> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Manfred Spraul <manfred@colorfullife.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r--mm/slab.c35
1 files changed, 17 insertions, 18 deletions
diff --git a/mm/slab.c b/mm/slab.c
index c714741b253..3233c4c7cbc 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -313,7 +313,7 @@ static int drain_freelist(struct kmem_cache *cache,
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(struct kmem_cache *cachep,
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_cache *cachep)
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, size_t size, size_t align,
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_cache *cachep, int limit,
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_cache *cachep, int limit,
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_cache *cachep)
if (err)
printk(KERN_ERR "enable_cpucache failed for %s, error %d.\n",
cachep->name, -err);
+ return err;
}
/*