5.1-CURRENT hangs on disk i/o? sysctl_old_user() non-sleepable locks

[Don Lewis]

On 18 Jun, Chris Shenton wrote:
> Don Lewis <truckman at FreeBSD.org> writes:
> 
>> Try the very untested patch below ...
> 
>> RCS file: /home/ncvs/src/sys/kern/uipc_syscalls.c,v
>> retrieving revision 1.150
>> Try the very untested patch below ...
>> diff -u -r1.150 uipc_syscalls.c
>> --- uipc_syscalls.c	12 Jun 2003 05:52:09 -0000	1.150
>> +++ uipc_syscalls.c	18 Jun 2003 03:14:42 -0000
>> @@ -1775,10 +1775,13 @@
>>  	 */
>>  	if ((error = fgetvp_read(td, uap->fd, &vp)) != 0)
>>  		goto done;
>> +	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
>>  	if (vp->v_type != VREG || VOP_GETVOBJECT(vp, &obj) != 0) {
>>  		error = EINVAL;
>> +		VOP_UNLOCK(vp, 0, td);
>>  		goto done;
>>  	}
>> +	VOP_UNLOCK(vp, 0, td);
> 
> Tried it, rebuilt kernel, rebooted, no affect :-(
> 
> You were correct about apache using it.  Doing a simple
> 
>   fetch http://pectopah/
> 
> causes the error, dropping me into ddb if panic enabled. A "tr" shows
> the same trace as I submitted yesterday :-(

Wierd ... I just tested the patch with ftpd which also uses sendfile()
and didn't get any complaints from DEBUG_VFS_LOCKS.

I'm going to go ahead and commit this patch.