Commit 51c23bd6 authored by Juergen Gross's avatar Juergen Gross
Browse files

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: 9e90e58c ("xen: evtchn: Allow shared registration of IRQ handers")
Reported-by: default avatarDemi Marie Obenour <demi@invisiblethingslab.com>
Tested-by: default avatarDemi Marie Obenour <demi@invisiblethingslab.com>
Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
Reviewed-by: default avatarOleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Link: https://lore.kernel.org/r/20240313071409.25913-2-jgross@suse.com


Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
parent 38620fc4

drivers/xen/evtchn.c

+6 −0
Original line number Diff line number Diff line
@@ -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);