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From: Fanny Dwargee <fdwargee6@gmail.com>
To: Wei Liu <wei.liu2@citrix.com>
Cc: xen-devel@lists.xen.org
Subject: Re: Stub domain crash on Xen v4.6.1
Date: Tue, 12 Apr 2016 11:44:16 +0200	[thread overview]
Message-ID: <CAOz6fc_Rn-36TKnWsF2SUgxo4z4STScp4v4j=2caB=zgLw4CKA@mail.gmail.com> (raw)
In-Reply-To: <20160412083613.GB18096@citrix.com>


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Wei,

It works now!

Many, many thanks for your invaluable time.

By the way, Do you know when the patch will be included in the stable-4.6
branch? Maybe will be on time for the 4.6.2 version?

IMHO is an important patch because of the added security shielding it
provides (allowing the use of stub domains on some cases).

Best regards,

Fanny

2016-04-12 10:36 GMT+02:00 Wei Liu <wei.liu2@citrix.com>:

> On Tue, Apr 05, 2016 at 05:17:00PM +0200, Fanny Dwargee wrote:
>
> (d21) read error -1 on /local/domain/21/device/vbd/768 at offset 0, num
> bytes 512
> (XEN) grant_table.c:525:d0v0 Bad flags (0) or dom (0). (expected dom 0)
> (d21) read error -1 on /local/domain/21/device/vbd/768 at offset 0, num
> bytes 512
> (XEN) grant_table.c:525:d0v0 Bad flags (0) or dom (0). (expected dom 0)
>
> This reminds me of a bug that would cause error in disk:
>
> http://lists.xen.org/archives/html/minios-devel/2016-04/msg00000.html
>
> Are you able to apply the patch in that thread and test?
>
> For your convenience I've attached the patch. It needs to be applied to
> xen.git/extras/mini-os.
>
> ---8<---
> From c519e3dfcdbc1edeac994dfa3918c175aae44983 Mon Sep 17 00:00:00 2001
> From: Samuel Thibault <samuel.thibault@ens-lyon.org>
> Date: Fri, 1 Apr 2016 20:17:01 +0200
> Subject: [PATCH] Mini-OS: netfront: fix off-by-one error introduced in
>  7c8f3483
>
> 7c8f3483 introduced a break within a loop in netfront.c such that
> cons and nr_consumed were no longer always being incremented. The
> offset at cons will be processed multiple times with the break in
> place.
>
> This commit reverts to using the "some" variable in the loop condition,
> but avoids ifdefs for the non-libc case. It also renames it to dobreak
> to make its usage clearer.
>
> Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
> Tested-by: Sarah Newman <srn@prgmr.com>
> ---
>  netfront.c | 20 ++++++--------------
>  1 file changed, 6 insertions(+), 14 deletions(-)
>
> diff --git a/netfront.c b/netfront.c
> index 0eca5b5..b8fac62 100644
> --- a/netfront.c
> +++ b/netfront.c
> @@ -97,19 +97,15 @@ void network_rx(struct netfront_dev *dev)
>  {
>      RING_IDX rp,cons,req_prod;
>      int nr_consumed, more, i, notify;
> -#ifdef HAVE_LIBC
> -    int some;
> -#endif
> +    int dobreak;
>
>      nr_consumed = 0;
>  moretodo:
>      rp = dev->rx.sring->rsp_prod;
>      rmb(); /* Ensure we see queued responses up to 'rp'. */
>
> -#ifdef HAVE_LIBC
> -    some = 0;
> -#endif
> -    for (cons = dev->rx.rsp_cons; cons != rp; nr_consumed++, cons++)
> +    dobreak = 0;
> +    for (cons = dev->rx.rsp_cons; cons != rp && !dobreak; nr_consumed++,
> cons++)
>      {
>          struct net_buffer* buf;
>          unsigned char* page;
> @@ -134,8 +130,8 @@ moretodo:
>                     len = dev->len;
>                 memcpy(dev->data, page+rx->offset, len);
>                 dev->rlen = len;
> -               some = 1;
> -                break;
> +               /* No need to receive the rest for now */
> +               dobreak = 1;
>             } else
>  #endif
>                 dev->netif_rx(page+rx->offset,rx->status);
> @@ -144,11 +140,7 @@ moretodo:
>      dev->rx.rsp_cons=cons;
>
>      RING_FINAL_CHECK_FOR_RESPONSES(&dev->rx,more);
> -#ifdef HAVE_LIBC
> -    if(more && !some) goto moretodo;
> -#else
> -    if(more) goto moretodo;
> -#endif
> +    if(more && !dobreak) goto moretodo;
>
>      req_prod = dev->rx.req_prod_pvt;
>
> --
> 2.1.4
>
>

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  reply	other threads:[~2016-04-12  9:44 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-04-05 15:17 Stub domain crash on Xen v4.6.1 Fanny Dwargee
2016-04-06 11:12 ` Wei Liu
2016-04-06 12:49   ` Fanny Dwargee
2016-04-07 16:13     ` Wei Liu
2016-04-07 16:51       ` Fanny Dwargee
2016-04-11 11:06         ` Wei Liu
2016-04-12  8:36 ` Wei Liu
2016-04-12  9:44   ` Fanny Dwargee [this message]
2016-04-12  9:49     ` Wei Liu
2016-04-12  8:27 Fanny Dwargee

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