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
