Re: Crash when unmounting NFS/TCP with -f

[Trond Myklebust]

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 ---
>  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@xxxxxxxxxx>
> ---
>  
>  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 ---