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xen/evtchn: avoid WARN() when unbinding an event channel

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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: 9e90e58c11 ("xen: evtchn: Allow shared registration of IRQ handers")
Reported-by: Demi Marie Obenour <demi@invisiblethingslab.com>
Tested-by: Demi Marie Obenour <demi@invisiblethingslab.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Link: https://lore.kernel.org/r/20240313071409.25913-2-jgross@suse.com
Signed-off-by: Juergen Gross <jgross@suse.com>
This commit is contained in:
Juergen Gross 2024-03-13 08:14:08 +01:00
parent 38620fc4e8
commit 51c23bd691
1 changed files with 6 additions and 0 deletions
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6
drivers/xen/evtchn.c
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@ -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);