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authorAlexey Dobriyan <adobriyan@gmail.com>2009-03-25 22:48:06 +0300
committerAlexey Dobriyan <adobriyan@gmail.com>2009-03-31 01:14:44 +0400
commit99b76233803beab302123d243eea9e41149804f3 (patch)
tree398178210fe66845ccd6fa4258ba762a87e023ad /net/sunrpc
parent3dec7f59c370c7b58184d63293c3dc984d475840 (diff)
downloadlwn-99b76233803beab302123d243eea9e41149804f3.tar.gz
lwn-99b76233803beab302123d243eea9e41149804f3.zip
proc 2/2: remove struct proc_dir_entry::owner
Setting ->owner as done currently (pde->owner = THIS_MODULE) is racy as correctly noted at bug #12454. Someone can lookup entry with NULL ->owner, thus not pinning enything, and release it later resulting in module refcount underflow. We can keep ->owner and supply it at registration time like ->proc_fops and ->data. But this leaves ->owner as easy-manipulative field (just one C assignment) and somebody will forget to unpin previous/pin current module when switching ->owner. ->proc_fops is declared as "const" which should give some thoughts. ->read_proc/->write_proc were just fixed to not require ->owner for protection. rmmod'ed directories will be empty and return "." and ".." -- no harm. And directories with tricky enough readdir and lookup shouldn't be modular. We definitely don't want such modular code. Removing ->owner will also make PDE smaller. So, let's nuke it. Kudos to Jeff Layton for reminding about this, let's say, oversight. http://bugzilla.kernel.org/show_bug.cgi?id=12454 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Diffstat (limited to 'net/sunrpc')
-rw-r--r--net/sunrpc/cache.c4
-rw-r--r--net/sunrpc/stats.c10
2 files changed, 2 insertions, 12 deletions
diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c
index 4735caad26ed..20029a79a5de 100644
--- a/net/sunrpc/cache.c
+++ b/net/sunrpc/cache.c
@@ -313,7 +313,6 @@ static int create_cache_proc_entries(struct cache_detail *cd)
cd->proc_ent = proc_mkdir(cd->name, proc_net_rpc);
if (cd->proc_ent == NULL)
goto out_nomem;
- cd->proc_ent->owner = cd->owner;
cd->channel_ent = cd->content_ent = NULL;
p = proc_create_data("flush", S_IFREG|S_IRUSR|S_IWUSR,
@@ -321,7 +320,6 @@ static int create_cache_proc_entries(struct cache_detail *cd)
cd->flush_ent = p;
if (p == NULL)
goto out_nomem;
- p->owner = cd->owner;
if (cd->cache_request || cd->cache_parse) {
p = proc_create_data("channel", S_IFREG|S_IRUSR|S_IWUSR,
@@ -329,7 +327,6 @@ static int create_cache_proc_entries(struct cache_detail *cd)
cd->channel_ent = p;
if (p == NULL)
goto out_nomem;
- p->owner = cd->owner;
}
if (cd->cache_show) {
p = proc_create_data("content", S_IFREG|S_IRUSR|S_IWUSR,
@@ -337,7 +334,6 @@ static int create_cache_proc_entries(struct cache_detail *cd)
cd->content_ent = p;
if (p == NULL)
goto out_nomem;
- p->owner = cd->owner;
}
return 0;
out_nomem:
diff --git a/net/sunrpc/stats.c b/net/sunrpc/stats.c
index 085372ef4feb..1ef6e46d9da2 100644
--- a/net/sunrpc/stats.c
+++ b/net/sunrpc/stats.c
@@ -262,14 +262,8 @@ void
rpc_proc_init(void)
{
dprintk("RPC: registering /proc/net/rpc\n");
- if (!proc_net_rpc) {
- struct proc_dir_entry *ent;
- ent = proc_mkdir("rpc", init_net.proc_net);
- if (ent) {
- ent->owner = THIS_MODULE;
- proc_net_rpc = ent;
- }
- }
+ if (!proc_net_rpc)
+ proc_net_rpc = proc_mkdir("rpc", init_net.proc_net);
}
void