On Dec 14, 2010, at 1:19 PM, J. Bruce Fields wrote:
On Mon, Dec 13, 2010 at 03:19:39PM -0500, Andy Adamson wrote:
Fixes this bug:
fedora-64 kernel: Invoking bc_svc_procass()
fedora-64 kernel: nfs_callback_authenticate SVC_DROP
fedora-64 kernel: BUG: unable to handle kernel NULL pointer
dereference at 0000000000000018 IP: [<ffffffffa0156140>]
svc_sock_free+0x32/0x56 [sunrpc]
Signed-off-by: Andy Adamson <andros@xxxxxxxxxx>
---
fs/nfs/callback.c | 3 +++
include/linux/sunrpc/svc_xprt.h | 1 +
net/sunrpc/svc_xprt.c | 3 ++-
3 files changed, 6 insertions(+), 1 deletions(-)
diff --git a/fs/nfs/callback.c b/fs/nfs/callback.c
index 93a8b3b..023a9eb 100644
--- a/fs/nfs/callback.c
+++ b/fs/nfs/callback.c
@@ -193,6 +193,9 @@ nfs41_callback_up(struct svc_serv *serv, struct
rpc_xprt *xprt)
serv->bc_xprt = bc_xprt;
xprt->bc_serv = serv;
+ /* socket is shared with the fore channel */
+ set_bit(XPT_SHARE_SOCK, &bc_xprt->xpt_flags);
+
INIT_LIST_HEAD(&serv->sv_cb_list);
spin_lock_init(&serv->sv_cb_lock);
init_waitqueue_head(&serv->sv_cb_waitq);
diff --git a/include/linux/sunrpc/svc_xprt.h b/include/linux/sunrpc/
svc_xprt.h
index aea0d43..600c669 100644
--- a/include/linux/sunrpc/svc_xprt.h
+++ b/include/linux/sunrpc/svc_xprt.h
@@ -62,6 +62,7 @@ struct svc_xprt {
#define XPT_DETACHED 10 /* detached from tempsocks list */
#define XPT_LISTENER 11 /* listening endpoint */
#define XPT_CACHE_AUTH 12 /* cache auth info */
+#define XPT_SHARE_SOCK 13 /* fore and back channel share socket */
struct svc_pool *xpt_pool; /* current pool iff queued */
struct svc_serv *xpt_server; /* service for transport */
diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
index ea2ff78..8c4d9ad 100644
--- a/net/sunrpc/svc_xprt.c
+++ b/net/sunrpc/svc_xprt.c
@@ -128,7 +128,8 @@ static void svc_xprt_free(struct kref *kref)
if (test_bit(XPT_CACHE_AUTH, &xprt->xpt_flags))
svcauth_unix_info_release(xprt);
put_net(xprt->xpt_net);
- xprt->xpt_ops->xpo_free(xprt);
+ if (!test_bit(XPT_SHARE_SOCK, &xprt->xpt_flags))
+ xprt->xpt_ops->xpo_free(xprt);
So when does the svc_xprt get freed if not here?
svc_sock_destroy frees the bc_xprt, called by svc_destroy on the serv-
>bc_xprt.
And why is it OK to do
the put_net() and module_put() but not the xpo_free()?
svc_sock_create() called only by nfs41_callback_up creates the
bc_xprt. It calls svc_xprt_init which calls get_net(), so put_net is
needed.
Hmmm. It looks like the module_put is also not needed - the matching
module_get is in svc_create_xprt() which is not called for the NFSv4.1
callback service. (but is called for the NFSv4.0 callback service ...
sheese).
I'll move the module_put so it is also not called when the
XPT_SHARE_SOCK flag is set.
Something feels wrong here....
Yeah - how about naming the server back channel xprt (bc_xprt) the
same as the client back channel xprt (bc_xprt)!!! How confusing is
THAT! :)
Thanks for the review.
-->Andy
--b.
module_put(owner);
}
--
1.6.6
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