Re: Crash when unmounting NFS/TCP with -f

[Trond Myklebust <trond.myklebust@fys.uio.no>]

to den 05.05.2005 Klokka 12:17 (+0200) skreiv Brice Goglin:

> Unable to handle kernel paging request at virtual address ffffff98
>  printing eip:
> e0aaa07a
> *pde = 00002067
> *pte = 00000000
> Oops: 0002 [#1]
> PREEMPT
> 
> Modules linked in: netconsole sd_mod usb_storage vfat fat loop isofs
> zlib_inflate nls_cp850 nls_iso8859_15 smbfs nfs lockd sunrpc i915 tun
> ipt_MASQUERADE iptable_nat ipt_state ip_conntrack iptable_filter
> ip_tables floppy uhci_hcd ehci_hcd dm_mod snd_intel8x0 snd_ac97_codec
> 
> CPU:    0
> EIP:    0060:[<e0aaa07a>]    Not tainted VLI
> EFLAGS: 00010297   (2.6.11=Macvin)
> EIP is at rpc_wake_up_status+0x6a/0x80 [sunrpc]
> eax: ffffff84   ebx: d0065888   ecx: 00000001   edx: c146e000
> esi: fffffffb   edi: d0065888   ebp: d0065800   esp: c146ef14
> ds: 007b   es: 007b   ss: 0068
> Process events/0 (pid: 3, threadinfo=c146e000 task=c1473020)
> Stack: c146ef44 d0065800 00000283 fffffffb e0aa710e d0065888 fffffffb
> 00120dcb c1473184 00000000 d0065904

Have you tried the attached patch? Andrew has already included it in the
-mm series.

Cheers,
  Trond

--- Begin Message ---

• To: trond.myklebust@fys.uio.no
• Subject: [PATCH 2/2] RPC: kick off socket connect operations faster
• From: Chuck Lever <cel@citi.umich.edu>
• Date: Fri, 29 Apr 2005 15:46:04 -0400
• Delivery-date: Fri, 29 Apr 2005 21:46:09 +0200

 Make the socket transport kick the event queue to start socket connects
 immediately.  This should improve responsiveness of applications that are
 sensitive to slow mount operations (like automounters).

 We are now also careful to cancel the connect worker before destroying
 the xprt.  This eliminates a race where xprt_destroy can finish before
 the connect worker is even allowed to run.

 Test-plan:
 Destructive testing (unplugging the network temporarily).  Connectathon
 with UDP and TCP.  Hard-code impossibly small connect timeout.

 Version: Fri, 29 Apr 2005 15:32:01 -0400
 
 Signed-off-by: Chuck Lever <cel@netapp.com>
---
 
 net/sunrpc/xprt.c |    9 ++++++++-
 1 files changed, 8 insertions(+), 1 deletion(-)
 
 
diff -X /home/cel/src/linux/dont-diff -Naurp 10-rpc-reconnect/net/sunrpc/xprt.c 11-xprt-flush-connects/net/sunrpc/xprt.c
--- 10-rpc-reconnect/net/sunrpc/xprt.c	2005-04-29 15:18:47.677108000 -0400
+++ 11-xprt-flush-connects/net/sunrpc/xprt.c	2005-04-29 15:29:36.637250000 -0400
@@ -569,8 +569,11 @@ void xprt_connect(struct rpc_task *task)
 		if (xprt->sock != NULL)
 			schedule_delayed_work(&xprt->sock_connect,
 					RPC_REESTABLISH_TIMEOUT);
-		else
+		else {
 			schedule_work(&xprt->sock_connect);
+			if (!RPC_IS_ASYNC(task))
+				flush_scheduled_work();
+		}
 	}
 	return;
  out_write:
@@ -1666,6 +1669,10 @@ xprt_shutdown(struct rpc_xprt *xprt)
 	rpc_wake_up(&xprt->backlog);
 	wake_up(&xprt->cong_wait);
 	del_timer_sync(&xprt->timer);
+
+	/* synchronously wait for connect worker to finish */
+	cancel_delayed_work(&xprt->sock_connect);
+	flush_scheduled_work();
 }
 
 /*

--- End Message ---