From: Fabiano Rosas <farosas@suse.de>
To: Michael Tokarev <mjt@tls.msk.ru>
Cc: Marco.Cavenati@eurecom.fr, mjt@tls.msk.ru, peterx@redhat.com,
qemu-devel@nongnu.org, qemu-trivial@nongnu.org,
Akihiko Odaki <odaki@rsg.ci.i.u-tokyo.ac.jp>
Subject: Re: [PATCH] migration: fix SEEK_CUR offset calculation in qio_channel_block_seek
Date: Tue, 26 Aug 2025 18:52:35 -0300 [thread overview]
Message-ID: <87plchkaxo.fsf@suse.de> (raw)
In-Reply-To: <dc23eaca-15f5-40be-89d0-2247cfe1f716@tls.msk.ru>
Michael Tokarev <mjt@tls.msk.ru> writes:
+CC Akihiko
> Hi!
>
> This is
>
> commit c0b32426ce56182c1ce2a12904f3a702c2ecc460
> Author: Marco Cavenati <Marco.Cavenati@eurecom.fr>
> Date: Wed Mar 26 17:22:30 2025 +0100
>
> migration: fix SEEK_CUR offset calculation in qio_channel_block_seek
>
> which went to 10.0.0-rc2, and has been cherry-picked to
> 7.2 and 9.2 stable series.
>
> Reportedly it breaks migration in 7.2.18 and up. Which is
> kinda strange, as it shouldn't do any harm?
>
Yeah, this is not it. Unless you're using colo or mapped-ram.
> https://bugs.debian.org/1112044
>
> any guess what's going on?
>
The virtio changes are probably the issue. One of them touches
mhdr.num_buffers, under mergeable_rx_bufs, which is migrated state. The
flag in turn depends on VIRTIO_NET_F_MRG_RXBUF, which is set on the
cmdline with -device virtio-net-pci,mrg_rxbuf= but also reset by
virtio_set_features_nocheck, if I'm reading this right.
Let's ask Akihiko.
> Thanks,
>
> /mjt
next prev parent reply other threads:[~2025-08-26 21:53 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-03-26 16:22 [PATCH] migration: fix SEEK_CUR offset calculation in qio_channel_block_seek Marco Cavenati
2025-03-26 16:48 ` Daniel P. Berrangé
2025-03-29 5:41 ` Michael Tokarev
2025-03-31 12:26 ` Fabiano Rosas
2025-08-26 20:32 ` Michael Tokarev
2025-08-26 21:27 ` Peter Xu
2025-08-26 21:52 ` Fabiano Rosas [this message]
2025-08-27 6:59 ` [PATCH] virtio: Call set_features during reset (was: migration: fix SEEK_CUR offset calculation in qio_channel_block_seek) Michael Tokarev
2025-08-28 0:57 ` [PATCH] migration: fix SEEK_CUR offset calculation in qio_channel_block_seek Akihiko Odaki
2025-08-29 8:34 ` [PATCH] virtio: Call set_features during reset Michael Tokarev
2025-08-29 14:40 ` Akihiko Odaki
2025-08-29 15:14 ` Michael Tokarev
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