Messages in this thread Patch in this message | | | Date | Mon, 17 Oct 2005 09:57:51 -0400 | From | Steve Dickson <> | Subject | [Fwd: [PATCH] NFS/RPC/GSS - oops in gss_pipe_release()] |
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Resending since this problem still appears to be in both the -mm and mainline kernels..
steved.
-------- Original Message -------- Subject: [PATCH] NFS/RPC/GSS - oops in gss_pipe_release() Date: Fri, 16 Sep 2005 13:40:15 -0400 From: Steve Dickson <SteveD@RedHat.com> To: nfs@lists.sourceforge.net
During some recent debugging I found that an oops can occur in gss_pipe_release() because the client handle that is being passed in has already been freed.
The scenario is as follows:
1) root# mount -o sec=krb5 server:/export /mnt/export 2) user$ ls /mnt/export (which hangs because user does not have the correct credentials) 3) root# reboot
The oops occurs when the /mnt/export filesystem is unmounted. The reason being is gss_pipe_release() was already called when the ls process was killed. The stack dump of the ls process was:
[<e09dda84>] gss_pipe_release+0x74/0xd8 [auth_rpcgss] [<e0a045c0>] rpc_pipe_release+0xa5/0xb9 [sunrpc] [<c015a9d6>] __fput+0x55/0x100 [<c0159626>] filp_close+0x59/0x5f [<c012363f>] put_files_struct+0x57/0xc0 [<c0124255>] do_exit+0x227/0x3de [<c01244fa>] sys_exit_group+0x0/0xd [<c02d120b>] syscall_call+0x7/0xb
So when the rpc_shutdown_client code is called via the umount: [<e09dda84>] gss_pipe_release+0x74/0xd8 [auth_rpcgss] [<e0a0447c>] rpc_close_pipes+0x80/0x9a [sunrpc] [<e0a04bb0>] rpc_depopulate+0xfb/0x142 [sunrpc] [<c01651bc>] cached_lookup+0xf/0x56 [<c0166410>] __lookup_hash+0x46/0x89 [<e0a05005>] rpc_rmdir+0x5a/0x89 [sunrpc] [<e09fcede>] rpcauth_free_credcache+0x87/0xd0 [sunrpc] [<e09f8431>] rpc_destroy_client+0x70/0xa4 [sunrpc] [<e09f8421>] rpc_destroy_client+0x60/0xa4 [sunrpc] [<e09f83ba>] rpc_shutdown_client+0xd1/0xd8 [sunrpc] [<c011e586>] default_wake_function+0x0/0xc [<e0aefe75>] nfs_kill_super+0x38/0x63 [nfs]
the client handle (which is in the rpc_inode) passed to gss_pipe_release() has already been freeded.
It appears from other places in the code (namely rpc_close_pipes()) that the only way to invalidate an rpc_inode is to set the ops pointer to NULL which is what the attached patch does.
Is there a better way to invalid an rpc_inode?
steved.
This patch stops the release_pipe() funtion from being called twice by invalidating the ops pointer in the rpc_inode when rpc_pipe_release() is called.
Signed-off-by: Steve Dickson <steved@redhat.com> ------------------------------------------------------ --- linux-2.6.13/net/sunrpc/rpc_pipe.c.orig 2005-08-28 19:41:01.000000000 -0400 +++ linux-2.6.13/net/sunrpc/rpc_pipe.c 2005-09-16 11:18:53.598157000 -0400 @@ -177,6 +177,8 @@ rpc_pipe_release(struct inode *inode, st __rpc_purge_upcall(inode, -EPIPE); if (rpci->ops->release_pipe) rpci->ops->release_pipe(inode); + if (!rpci->nreaders && !rpci->nwriters) + rpci->ops = NULL; out: up(&inode->i_sem); return 0;
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