path: root/fs/nfsd
diff options
authorBruce Allan <bwa@us.ibm.com>2005-09-06 15:17:08 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2005-09-07 16:57:25 -0700
commitf35279d3f713e5c97b98cbdbf47d98f79942c11f (patch)
treecdf9acab7e7fda7ae1eae152861d4048b7f6dffc /fs/nfsd
parentd013a068a5675ecd8e71f585a44e7af0798a4307 (diff)
[PATCH] sunrpc: cache_register can use wrong module reference
When registering an RPC cache, cache_register() always sets the owner as the sunrpc module. However, there are RPC caches owned by other modules. With the incorrect owner setting, the real owning module can be removed potentially with an open reference to the cache from userspace. For example, if one were to stop the nfs server and unmount the nfsd filesystem, the nfsd module could be removed eventhough rpc.idmapd had references to the idtoname and nametoid caches (i.e. /proc/net/rpc/nfs4.<cachename>/channel is still open). This resulted in a system panic on one of our machines when attempting to restart the nfs services after reloading the nfsd module. The following patch adds a 'struct module *owner' field in struct cache_detail. The owner is further assigned to the struct proc_dir_entry in cache_register() so that the module cannot be unloaded while user-space daemons have an open reference on the associated file under /proc. Signed-off-by: Bruce Allan <bwa@us.ibm.com> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Cc: Neil Brown <neilb@cse.unsw.edu.au> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'fs/nfsd')
2 files changed, 9 insertions, 2 deletions
diff --git a/fs/nfsd/export.c b/fs/nfsd/export.c
index 9a11aa39e2e..057aff74550 100644
--- a/fs/nfsd/export.c
+++ b/fs/nfsd/export.c
@@ -26,6 +26,7 @@
#include <linux/namei.h>
#include <linux/mount.h>
#include <linux/hash.h>
+#include <linux/module.h>
#include <linux/sunrpc/svc.h>
#include <linux/nfsd/nfsd.h>
@@ -221,6 +222,7 @@ static int expkey_show(struct seq_file *m,
struct cache_detail svc_expkey_cache = {
+ .owner = THIS_MODULE,
.hash_size = EXPKEY_HASHMAX,
.hash_table = expkey_table,
.name = "nfsd.fh",
@@ -456,6 +458,7 @@ static int svc_export_show(struct seq_file *m,
return 0;
struct cache_detail svc_export_cache = {
+ .owner = THIS_MODULE,
.hash_size = EXPORT_HASHMAX,
.hash_table = export_table,
.name = "nfsd.export",
diff --git a/fs/nfsd/nfs4idmap.c b/fs/nfsd/nfs4idmap.c
index 5605a26efc5..13369650cdf 100644
--- a/fs/nfsd/nfs4idmap.c
+++ b/fs/nfsd/nfs4idmap.c
@@ -187,6 +187,7 @@ static int idtoname_parse(struct cache_detail *, char *, int);
static struct ent *idtoname_lookup(struct ent *, int);
static struct cache_detail idtoname_cache = {
+ .owner = THIS_MODULE,
.hash_size = ENT_HASHMAX,
.hash_table = idtoname_table,
.name = "nfs4.idtoname",
@@ -320,6 +321,7 @@ static struct ent *nametoid_lookup(struct ent *, int);
static int nametoid_parse(struct cache_detail *, char *, int);
static struct cache_detail nametoid_cache = {
+ .owner = THIS_MODULE,
.hash_size = ENT_HASHMAX,
.hash_table = nametoid_table,
.name = "nfs4.nametoid",
@@ -404,8 +406,10 @@ nfsd_idmap_init(void)
- cache_unregister(&idtoname_cache);
- cache_unregister(&nametoid_cache);
+ if (cache_unregister(&idtoname_cache))
+ printk(KERN_ERR "nfsd: failed to unregister idtoname cache\n");
+ if (cache_unregister(&nametoid_cache))
+ printk(KERN_ERR "nfsd: failed to unregister nametoid cache\n");