Re: PROBLEM: Oops, nfsd, networking

[Neil Brown]

On Monday June 28, bvaughan@xxxxxxxxxxxxxx wrote:
> NFSD crash at large MTU and odd wsize/rsize.
>  

Thanks for the report.  It is very odd.
It seems to be crashing in fs/nfsd/nfs3xdrc.:nfs3svc_decode_writeargs
at:

	while (len > args->vec[v].iov_len) {
		len -= args->vec[v].iov_len;
		v++;
		args->vec[v].iov_base = page_address(rqstp->rq_argpages[v]);
		args->vec[v].iov_len = PAGE_SIZE;
	}

It looks like rqstp->rq_argpages[v] is NULL, and that is causing the
oops.
Obviously, that shouldn't happen :-)

Would you be able to change that code to:
	while (len > args->vec[v].iov_len) {
		len -= args->vec[v].iov_len;
		v++;
		if (rqstp->rq_argpages[v] == NULL) {
			printk("NULL page at %d, c=%d al=%d l=%d pl=%d\n",
				v, args->count, args->len, len,	rqstp->rq_arg.len);
		        BUG();
		}
		args->vec[v].iov_base = page_address(rqstp->rq_argpages[v]);
		args->vec[v].iov_len = PAGE_SIZE;
	}

(i.e. add the if() { printk..} bit).
and tell me what gets printed out?

Thanks,
NeilBrown
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