On Tue, Mar 12, 2024 at 02:10:02PM +0100, Juergen Gross wrote: > On 30.11.23 03:34, Marek Marczykowski-Górecki wrote: > > Hi, > > > > While testing 6.7-rc3 on Qubes OS I found several warning like in the > > subject in dom0 log. I see them when running 6.7-rc1 too. I'm not sure > > what exactly triggers the issue, but my guess would be unbinding an > > event channel from userspace (closing vchan connection). > > > > Specific message: > > > > [ 83.973377] ------------[ cut here ]------------ > > [ 83.975523] Interrupt for port 77, but apparently not enabled; per-user > > 00000000a0e9f1d1 > > Finally I think I have a fix (thanks to Demi for finding the problematic patch > through bisecting). > > Could you please try the attached patch? It is based on current upstream, but > I think it should apply to 6.7 or stable 6.6, too. > > > Juergen
> From 9d673c37b2d0c9aa274c53f619c4e9e43a419f41 Mon Sep 17 00:00:00 2001
> From: Juergen Gross <jgr...@suse.com>
> To: linux-ker...@vger.kernel.org
> Cc: Juergen Gross <jgr...@suse.com>
> Cc: Stefano Stabellini <sstabell...@kernel.org>
> Cc: Oleksandr Tyshchenko <oleksandr_tyshche...@epam.com>
> Cc: xen-devel@lists.xenproject.org
> Date: Tue, 12 Mar 2024 13:52:24 +0100
> Subject: [PATCH] xen/evtchn: avoid WARN() when unbinding an event channel
>
> When unbinding a user event channel, the related handler might be
> called a last time in case the kernel was built with
> CONFIG_DEBUG_SHIRQ. This might cause a WARN() in the handler.
>
> Avoid that by adding an "unbinding" flag to struct user_event which
> will short circuit the handler.
>
> Fixes: 9e90e58c11b7 ("xen: evtchn: Allow shared registration of IRQ handers")
> Signed-off-by: Juergen Gross <jgr...@suse.com>
> ---
> drivers/xen/evtchn.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/drivers/xen/evtchn.c b/drivers/xen/evtchn.c
> index 59717628ca42..f6a2216c2c87 100644
> --- a/drivers/xen/evtchn.c
> +++ b/drivers/xen/evtchn.c
> @@ -85,6 +85,7 @@ struct user_evtchn {
> struct per_user_data *user;
> evtchn_port_t port;
> bool enabled;
> + bool unbinding;
> };
>
> static void evtchn_free_ring(evtchn_port_t *ring)
> @@ -164,6 +165,10 @@ static irqreturn_t evtchn_interrupt(int irq, void *data)
> struct per_user_data *u = evtchn->user;
> unsigned int prod, cons;
>
> + /* Handler might be called when tearing down the IRQ. */
> + if (evtchn->unbinding)
> + return IRQ_HANDLED;
> +
> WARN(!evtchn->enabled,
> "Interrupt for port %u, but apparently not enabled; per-user %p\n",
> evtchn->port, u);
> @@ -421,6 +426,7 @@ static void evtchn_unbind_from_user(struct per_user_data
> *u,
>
> BUG_ON(irq < 0);
>
> + evtchn->unbinding = true;
> unbind_from_irqhandler(irq, evtchn);
>
> del_evtchn(u, evtchn);
> --
> 2.35.3
That fixes the problem, thanks! Code looks good to me.
Reported-by: Demi Marie Obenour <d...@invisiblethingslab.com>
Tested-by: Demi Marie Obenour <d...@invisiblethingslab.com>
--
Sincerely,
Demi Marie Obenour (she/her/hers)
Invisible Things Lab
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