The patch titled
Subject: nfs42: use a specific kmem_cache to allocate nfs4_xattr_entry
has been added to the -mm tree. Its filename is
nfs42-use-a-specific-kmem_cache-to-allocate-nfs4_xattr_entry.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/nfs42-use-a-specific-kmem_cache-to-allocate-nfs4_xattr_entry.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/nfs42-use-a-specific-kmem_cache-to-allocate-nfs4_xattr_entry.patch
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
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------------------------------------------------------
From: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Subject: nfs42: use a specific kmem_cache to allocate nfs4_xattr_entry
Fixes a null-pointer deref in nfs4.
If we want to add the allocated objects to its list_lru, we should use
kmem_cache_alloc_lru() to allocate objects. So intruduce
nfs4_xattr_entry_cachep which is used to allocate nfs4_xattr_entry.
Link: https://lkml.kernel.org/r/164876616694.25542.14010655277238655246@xxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Tested-by: NeilBrown <neilb@xxxxxxx>
Cc: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/nfs/nfs42xattr.c | 95 ++++++++++++++++++++----------------------
1 file changed, 47 insertions(+), 48 deletions(-)
--- a/fs/nfs/nfs42xattr.c~nfs42-use-a-specific-kmem_cache-to-allocate-nfs4_xattr_entry
+++ a/fs/nfs/nfs42xattr.c
@@ -81,7 +81,7 @@ struct nfs4_xattr_entry {
struct hlist_node hnode;
struct list_head lru;
struct list_head dispose;
- char *xattr_name;
+ const char *xattr_name;
void *xattr_value;
size_t xattr_size;
struct nfs4_xattr_bucket *bucket;
@@ -98,6 +98,7 @@ static struct list_lru nfs4_xattr_entry_
static struct list_lru nfs4_xattr_large_entry_lru;
static struct kmem_cache *nfs4_xattr_cache_cachep;
+static struct kmem_cache *nfs4_xattr_entry_cachep;
/*
* Hashing helper functions.
@@ -177,49 +178,28 @@ nfs4_xattr_alloc_entry(const char *name,
{
struct nfs4_xattr_entry *entry;
void *valp;
- char *namep;
- size_t alloclen, slen;
- char *buf;
- uint32_t flags;
+ const char *namep;
+ uint32_t flags = len > PAGE_SIZE ? NFS4_XATTR_ENTRY_EXTVAL : 0;
+ gfp_t gfp = GFP_KERNEL;
+ struct list_lru *lru;
BUILD_BUG_ON(sizeof(struct nfs4_xattr_entry) +
XATTR_NAME_MAX + 1 > PAGE_SIZE);
- alloclen = sizeof(struct nfs4_xattr_entry);
- if (name != NULL) {
- slen = strlen(name) + 1;
- alloclen += slen;
- } else
- slen = 0;
-
- if (alloclen + len <= PAGE_SIZE) {
- alloclen += len;
- flags = 0;
- } else {
- flags = NFS4_XATTR_ENTRY_EXTVAL;
- }
-
- buf = kmalloc(alloclen, GFP_KERNEL);
- if (buf == NULL)
+ lru = flags & NFS4_XATTR_ENTRY_EXTVAL ? &nfs4_xattr_large_entry_lru :
+ &nfs4_xattr_entry_lru;
+ entry = kmem_cache_alloc_lru(nfs4_xattr_entry_cachep, lru, gfp);
+ if (!entry)
return NULL;
- entry = (struct nfs4_xattr_entry *)buf;
-
- if (name != NULL) {
- namep = buf + sizeof(struct nfs4_xattr_entry);
- memcpy(namep, name, slen);
- } else {
- namep = NULL;
- }
-
-
- if (flags & NFS4_XATTR_ENTRY_EXTVAL) {
- valp = kvmalloc(len, GFP_KERNEL);
- if (valp == NULL) {
- kfree(buf);
- return NULL;
- }
- } else if (len != 0) {
- valp = buf + sizeof(struct nfs4_xattr_entry) + slen;
+ kref_init(&entry->ref);
+ namep = kstrdup_const(name, gfp);
+ if (!namep && name)
+ goto free_buf;
+
+ if (len != 0) {
+ valp = kvmalloc(len, gfp);
+ if (!valp)
+ goto free_name;
} else
valp = NULL;
@@ -232,23 +212,23 @@ nfs4_xattr_alloc_entry(const char *name,
entry->flags = flags;
entry->xattr_value = valp;
- kref_init(&entry->ref);
entry->xattr_name = namep;
entry->xattr_size = len;
- entry->bucket = NULL;
- INIT_LIST_HEAD(&entry->lru);
- INIT_LIST_HEAD(&entry->dispose);
- INIT_HLIST_NODE(&entry->hnode);
return entry;
+free_name:
+ kfree_const(namep);
+free_buf:
+ kmem_cache_free(nfs4_xattr_entry_cachep, entry);
+ return NULL;
}
static void
nfs4_xattr_free_entry(struct nfs4_xattr_entry *entry)
{
- if (entry->flags & NFS4_XATTR_ENTRY_EXTVAL)
- kvfree(entry->xattr_value);
- kfree(entry);
+ kvfree(entry->xattr_value);
+ kfree_const(entry->xattr_name);
+ kmem_cache_free(nfs4_xattr_entry_cachep, entry);
}
static void
@@ -289,7 +269,7 @@ nfs4_xattr_alloc_cache(void)
{
struct nfs4_xattr_cache *cache;
- cache = kmem_cache_alloc(nfs4_xattr_cache_cachep, GFP_KERNEL);
+ cache = kmem_cache_alloc_lru(nfs4_xattr_cache_cachep, &nfs4_xattr_cache_lru, GFP_KERNEL);
if (cache == NULL)
return NULL;
@@ -991,6 +971,16 @@ static void nfs4_xattr_cache_init_once(v
INIT_LIST_HEAD(&cache->dispose);
}
+static void nfs4_xattr_entry_init_once(void *p)
+{
+ struct nfs4_xattr_entry *entry = p;
+
+ entry->bucket = NULL;
+ INIT_LIST_HEAD(&entry->lru);
+ INIT_LIST_HEAD(&entry->dispose);
+ INIT_HLIST_NODE(&entry->hnode);
+}
+
int __init nfs4_xattr_cache_init(void)
{
int ret = 0;
@@ -1002,6 +992,13 @@ int __init nfs4_xattr_cache_init(void)
if (nfs4_xattr_cache_cachep == NULL)
return -ENOMEM;
+ nfs4_xattr_entry_cachep = kmem_cache_create("nfs4_xattr_entry",
+ sizeof(struct nfs4_xattr_entry), 0,
+ (SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD | SLAB_ACCOUNT),
+ nfs4_xattr_entry_init_once);
+ if (!nfs4_xattr_entry_cachep)
+ goto out5;
+
ret = list_lru_init_memcg(&nfs4_xattr_large_entry_lru,
&nfs4_xattr_large_entry_shrinker);
if (ret)
@@ -1039,6 +1036,8 @@ out2:
out3:
list_lru_destroy(&nfs4_xattr_large_entry_lru);
out4:
+ kmem_cache_destroy(nfs4_xattr_entry_cachep);
+out5:
kmem_cache_destroy(nfs4_xattr_cache_cachep);
return ret;
_
Patches currently in -mm which might be from songmuchun@xxxxxxxxxxxxx are
mm-kfence-fix-objcgs-vector-allocation.patch
nfs42-use-a-specific-kmem_cache-to-allocate-nfs4_xattr_entry.patch
mm-hugetlb_vmemmap-introduce-arch_want_hugetlb_page_free_vmemmap.patch
arm64-mm-hugetlb-enable-hugetlb_page_free_vmemmap-for-arm64.patch
