2022-06-30 19:24:15

by Michael S. Tsirkin

[permalink] [raw]
Subject: [PATCH] virtio: VIRTIO_HARDEN_NOTIFICATION is broken

This option doesn't really work and breaks too many drivers.
Not yet sure what's the right thing to do, for now
let's make sure randconfig isn't broken by this.

Fixes: c346dae4f3fb ("virtio: disable notification hardening by default")
Cc: "Jason Wang" <[email protected]>
Signed-off-by: Michael S. Tsirkin <[email protected]>
---
drivers/virtio/Kconfig | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig
index e1556d2a355a..afb9051e0125 100644
--- a/drivers/virtio/Kconfig
+++ b/drivers/virtio/Kconfig
@@ -31,11 +31,12 @@ if VIRTIO_MENU

config VIRTIO_HARDEN_NOTIFICATION
bool "Harden virtio notification"
+ depends on BROKEN
help
Enable this to harden the device notifications and suppress
those that happen at a time where notifications are illegal.

- Experimental: Note that several drivers still have bugs that
+ Experimental: Note that several drivers still have issues that
may cause crashes or hangs when correct handling of
notifications is enforced; depending on the subset of
drivers and devices you use, this may or may not work.
--
MST


2022-07-01 01:27:25

by Jason Wang

[permalink] [raw]
Subject: Re: [PATCH] virtio: VIRTIO_HARDEN_NOTIFICATION is broken

On Fri, Jul 1, 2022 at 3:16 AM Michael S. Tsirkin <[email protected]> wrote:
>
> This option doesn't really work and breaks too many drivers.
> Not yet sure what's the right thing to do, for now
> let's make sure randconfig isn't broken by this.
>
> Fixes: c346dae4f3fb ("virtio: disable notification hardening by default")
> Cc: "Jason Wang" <[email protected]>
> Signed-off-by: Michael S. Tsirkin <[email protected]>

Acked-by: Jason Wang <[email protected]>

> ---
> drivers/virtio/Kconfig | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig
> index e1556d2a355a..afb9051e0125 100644
> --- a/drivers/virtio/Kconfig
> +++ b/drivers/virtio/Kconfig
> @@ -31,11 +31,12 @@ if VIRTIO_MENU
>
> config VIRTIO_HARDEN_NOTIFICATION
> bool "Harden virtio notification"
> + depends on BROKEN
> help
> Enable this to harden the device notifications and suppress
> those that happen at a time where notifications are illegal.
>
> - Experimental: Note that several drivers still have bugs that
> + Experimental: Note that several drivers still have issues that
> may cause crashes or hangs when correct handling of
> notifications is enforced; depending on the subset of
> drivers and devices you use, this may or may not work.
> --
> MST
>

2022-07-01 07:13:22

by Cornelia Huck

[permalink] [raw]
Subject: Re: [PATCH] virtio: VIRTIO_HARDEN_NOTIFICATION is broken

On Thu, Jun 30 2022, "Michael S. Tsirkin" <[email protected]> wrote:

> This option doesn't really work and breaks too many drivers.
> Not yet sure what's the right thing to do, for now
> let's make sure randconfig isn't broken by this.
>
> Fixes: c346dae4f3fb ("virtio: disable notification hardening by default")
> Cc: "Jason Wang" <[email protected]>
> Signed-off-by: Michael S. Tsirkin <[email protected]>
> ---
> drivers/virtio/Kconfig | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)

Reviewed-by: Cornelia Huck <[email protected]>

Subject: Re: [PATCH] virtio: VIRTIO_HARDEN_NOTIFICATION is broken

Hi, this is your Linux kernel regression tracker.

On 30.06.22 21:16, Michael S. Tsirkin wrote:
> This option doesn't really work and breaks too many drivers.
> Not yet sure what's the right thing to do, for now
> let's make sure randconfig isn't broken by this.
>
> Fixes: c346dae4f3fb ("virtio: disable notification hardening by default")
> Cc: "Jason Wang" <[email protected]>
> Signed-off-by: Michael S. Tsirkin <[email protected]>
> ---
> drivers/virtio/Kconfig | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig
> index e1556d2a355a..afb9051e0125 100644
> --- a/drivers/virtio/Kconfig
> +++ b/drivers/virtio/Kconfig
> @@ -31,11 +31,12 @@ if VIRTIO_MENU
>
> config VIRTIO_HARDEN_NOTIFICATION
> bool "Harden virtio notification"
> + depends on BROKEN
> [...]

Michael, just wondering: together with c346dae4f3fb this patch afaics
fixes a 5.19 regression I've been tracking. It's now for 10 days in
next, but not yet mainlined. Is that intentional or do you still plan to
submit it in this cycle?

Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat)

P.S.: As the Linux kernel's regression tracker I deal with a lot of
reports and sometimes miss something important when writing mails like
this. If that's the case here, don't hesitate to tell me in a public
reply, it's in everyone's interest to set the public record straight.