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authorBruce Allan <bwa@us.ibm.com>2005-09-06 18:17:08 -0400
committerLinus Torvalds <torvalds@g5.osdl.org>2005-09-07 19:57:25 -0400
commitf35279d3f713e5c97b98cbdbf47d98f79942c11f (patch)
treecdf9acab7e7fda7ae1eae152861d4048b7f6dffc /include/linux/sunrpc/cache.h
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 'include/linux/sunrpc/cache.h')
-rw-r--r--include/linux/sunrpc/cache.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/sunrpc/cache.h b/include/linux/sunrpc/cache.h
index 6864063d1b9f..c4e3ea7cf154 100644
--- a/include/linux/sunrpc/cache.h
+++ b/include/linux/sunrpc/cache.h
@@ -60,6 +60,7 @@ struct cache_head {
60#define CACHE_NEW_EXPIRY 120 /* keep new things pending confirmation for 120 seconds */ 60#define CACHE_NEW_EXPIRY 120 /* keep new things pending confirmation for 120 seconds */
61 61
62struct cache_detail { 62struct cache_detail {
63 struct module * owner;
63 int hash_size; 64 int hash_size;
64 struct cache_head ** hash_table; 65 struct cache_head ** hash_table;
65 rwlock_t hash_lock; 66 rwlock_t hash_lock;