| Message ID | 20240313071409.25913-2-jgross@suse.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 51c23bd691c0f1fb95b29731c356c6fd69925d17 |
| Headers | show |
| Series | xen: two fixes related to event channels | expand |
On 13.03.24 09:14, Juergen Gross wrote: Hello Juergen > 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") > 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> > --- > 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);
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);
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") Reported-by: Demi Marie Obenour <demi@invisiblethingslab.com> Tested-by: Demi Marie Obenour <demi@invisiblethingslab.com> Signed-off-by: Juergen Gross <jgross@suse.com> --- drivers/xen/evtchn.c | 6 ++++++ 1 file changed, 6 insertions(+)