| Message ID | 20130918151603.GC12030@fieldses.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, 2013-09-18 at 11:16 -0400, J. Bruce Fields wrote: > From: "J. Bruce Fields" <bfields@redhat.com> > > This fixes a regression since eb6dc19d8e72ce3a957af5511d20c0db0a8bd007 > "RPCSEC_GSS: Share all credential caches on a per-transport basis" which > could cause an occasional oops in the nfsd code (see below). > > The problem was that an auth was left referencing a client that had been > freed. To avoid this we need to ensure that auths are shared only > between descendants of a common client; the fact that a clone of an > rpc_client takes a reference on its parent then ensures that the parent > client will last as long as the auth. > > Also add a comment explaining what I think was the intention of this > code. > > general protection fault: 0000 [#1] PREEMPT SMP > Modules linked in: rpcsec_gss_krb5 nfsd auth_rpcgss oid_registry nfs_acl lockd sunrpc > CPU: 3 PID: 4071 Comm: kworker/u8:2 Not tainted 3.11.0-rc2-00182-g025145f #1665 > Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 > Workqueue: nfsd4_callbacks nfsd4_do_callback_rpc [nfsd] > task: ffff88003e206080 ti: ffff88003c384000 task.ti: ffff88003c384000 > RIP: 0010:[<ffffffffa00001f3>] [<ffffffffa00001f3>] rpc_net_ns+0x53/0x70 [sunrpc] > RSP: 0000:ffff88003c385ab8 EFLAGS: 00010246 > RAX: 6b6b6b6b6b6b6b6b RBX: ffff88003af9a800 RCX: 0000000000000002 > RDX: ffffffffa00001a5 RSI: 0000000000000001 RDI: ffffffff81e284e0 > RBP: ffff88003c385ad8 R08: 0000000000000001 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000015 R12: ffff88003c990840 > R13: ffff88003c990878 R14: ffff88003c385ba8 R15: ffff88003e206080 > FS: 0000000000000000(0000) GS:ffff88003fd80000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b > CR2: 00007fcdf737e000 CR3: 000000003ad2b000 CR4: 00000000000006e0 > Stack: > ffffffffa00001a5 0000000000000006 0000000000000006 ffff88003af9a800 > ffff88003c385b08 ffffffffa00d52a4 ffff88003c385ba8 ffff88003c751bd8 > ffff88003c751bc0 ffff88003e113600 ffff88003c385b18 ffffffffa00d530c > Call Trace: > [<ffffffffa00001a5>] ? rpc_net_ns+0x5/0x70 [sunrpc] > [<ffffffffa00d52a4>] __gss_pipe_release+0x54/0x90 [auth_rpcgss] > [<ffffffffa00d530c>] gss_pipe_free+0x2c/0x30 [auth_rpcgss] > [<ffffffffa00d678b>] gss_destroy+0x9b/0xf0 [auth_rpcgss] > [<ffffffffa000de63>] rpcauth_release+0x23/0x30 [sunrpc] > [<ffffffffa0001e81>] rpc_release_client+0x51/0xb0 [sunrpc] > [<ffffffffa00020d5>] rpc_shutdown_client+0xe5/0x170 [sunrpc] > [<ffffffff81098a14>] ? cpuacct_charge+0xa4/0xb0 > [<ffffffff81098975>] ? cpuacct_charge+0x5/0xb0 > [<ffffffffa019556f>] nfsd4_process_cb_update.isra.17+0x2f/0x210 [nfsd] > [<ffffffff819a4ac0>] ? _raw_spin_unlock_irq+0x30/0x60 > [<ffffffff819a4acb>] ? _raw_spin_unlock_irq+0x3b/0x60 > [<ffffffff810703ab>] ? process_one_work+0x15b/0x510 > [<ffffffffa01957dd>] nfsd4_do_callback_rpc+0x8d/0xa0 [nfsd] > [<ffffffff8107041e>] process_one_work+0x1ce/0x510 > [<ffffffff810703ab>] ? process_one_work+0x15b/0x510 > [<ffffffff810712ab>] worker_thread+0x11b/0x370 > [<ffffffff81071190>] ? manage_workers.isra.24+0x2b0/0x2b0 > [<ffffffff8107854b>] kthread+0xdb/0xe0 > [<ffffffff819a4ac0>] ? _raw_spin_unlock_irq+0x30/0x60 > [<ffffffff81078470>] ? __init_kthread_worker+0x70/0x70 > [<ffffffff819ac7dc>] ret_from_fork+0x7c/0xb0 > [<ffffffff81078470>] ? __init_kthread_worker+0x70/0x70 > Code: a5 01 00 a0 31 d2 31 f6 48 c7 c7 e0 84 e2 81 e8 f4 91 0a e1 48 8b 43 60 48 c7 c2 a5 01 00 a0 be 01 00 00 00 48 c7 c7 e0 84 e2 81 <48> 8b 98 10 07 00 00 e8 91 8f 0a e1 e8 > +3c 4e 07 e1 48 83 c4 18 > RIP [<ffffffffa00001f3>] rpc_net_ns+0x53/0x70 [sunrpc] > RSP <ffff88003c385ab8> > > Signed-off-by: J. Bruce Fields <bfields@redhat.com> > --- > net/sunrpc/auth_gss/auth_gss.c | 11 +++++++++++ > 1 file changed, 11 insertions(+) > > On Tue, Sep 17, 2013 at 06:19:14PM -0400, J. Bruce Fields wrote: > > fixes the problem. I can send in a proper patch if you think that makes > > sense.... > > Here's my attempt. That looks good. Thanks! Trond -- Trond Myklebust Linux NFS client maintainer NetApp Trond.Myklebust@netapp.com www.netapp.com
diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c index fcac5d1..0846566 100644 --- a/net/sunrpc/auth_gss/auth_gss.c +++ b/net/sunrpc/auth_gss/auth_gss.c @@ -1075,6 +1075,15 @@ gss_destroy(struct rpc_auth *auth) kref_put(&gss_auth->kref, gss_free_callback); } +/* + * Auths may be shared between rpc clients that were cloned from a + * common client with the same xprt, if they also share the flavor and + * target_name. + * + * The auth is looked up from the oldest parent sharing the same + * cl_xprt, and the auth itself references only that common parent + * (which is guaranteed to last as long as any of its descendants). + */ static struct gss_auth * gss_auth_find_or_add_hashed(struct rpc_auth_create_args *args, struct rpc_clnt *clnt, @@ -1088,6 +1097,8 @@ gss_auth_find_or_add_hashed(struct rpc_auth_create_args *args, gss_auth, hash, hashval) { + if (gss_auth->client != clnt) + continue; if (gss_auth->rpc_auth.au_flavor != args->pseudoflavor) continue; if (gss_auth->target_name != args->target_name) {