Commit ebed9203 authored by Trond Myklebust's avatar Trond Myklebust
Browse files

NFS: Fix an allocation-under-spinlock bug 



sunrpc_cache_update() will always call detail->update() from inside the
detail->hash_lock, so it cannot allocate memory.

Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@kernel.org
parent 9fcfe0c8

fs/nfs/dns_resolve.c

+15 −3
Original line number Diff line number Diff line
@@ -36,6 +36,19 @@ struct nfs_dns_ent { 
};





static void nfs_dns_ent_update(struct cache_head *cnew,

		struct cache_head *ckey)

{

	struct nfs_dns_ent *new;

	struct nfs_dns_ent *key;



	new = container_of(cnew, struct nfs_dns_ent, h);

	key = container_of(ckey, struct nfs_dns_ent, h);



	memcpy(&new->addr, &key->addr, key->addrlen);

	new->addrlen = key->addrlen;

}



static void nfs_dns_ent_init(struct cache_head *cnew,

		struct cache_head *ckey)

{
@@ -49,8 +62,7 @@ static void nfs_dns_ent_init(struct cache_head *cnew, 
	new->hostname = kstrndup(key->hostname, key->namelen, GFP_KERNEL);

	if (new->hostname) {

		new->namelen = key->namelen;

		memcpy(&new->addr, &key->addr, key->addrlen);

		new->addrlen = key->addrlen;

		nfs_dns_ent_update(cnew, ckey);

	} else {

		new->namelen = 0;

		new->addrlen = 0;
@@ -234,7 +246,7 @@ static struct cache_detail nfs_dns_resolve = { 
	.cache_show = nfs_dns_show,

	.match = nfs_dns_match,

	.init = nfs_dns_ent_init,

	.update = nfs_dns_ent_init,

	.update = nfs_dns_ent_update,

	.alloc = nfs_dns_ent_alloc,

};