From 9d673c37b2d0c9aa274c53f619c4e9e43a419f41 Mon Sep 17 00:00:00 2001 From: Juergen Gross To: linux-kernel@xxxxxxxxxxxxxxx Cc: Juergen Gross Cc: Stefano Stabellini Cc: Oleksandr Tyshchenko Cc: xen-devel@xxxxxxxxxxxxxxxxxxxx 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 --- 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