From: Julien Grall <[email protected]>
After Commit 3499ba8198cad ("xen: Fix event channel callback via
INTX/GSI"), xenbus_probe() will be called too early on Arm. This will
recent to a guest hang during boot.
If there hang wasn't there, we would have ended up to call
xenbus_probe() twice (the second time is in xenbus_probe_initcall()).
We don't need to initialize xenbus_probe() early for Arm guest.
Therefore, the call in xen_guest_init() is now removed.
After this change, there is no more external caller for xenbus_probe().
So the function is turned to a static one. Interestingly there were two
prototypes for it.
Fixes: 3499ba8198cad ("xen: Fix event channel callback via INTX/GSI")
Reported-by: Ian Jackson <[email protected]>
Signed-off-by: Julien Grall <[email protected]>
CC: [email protected]
---
The offending commit unfortunately got backport to stable trees. So
this will need to be backported as well.
---
arch/arm/xen/enlighten.c | 2 --
drivers/xen/xenbus/xenbus.h | 1 -
drivers/xen/xenbus/xenbus_probe.c | 2 +-
include/xen/xenbus.h | 2 --
4 files changed, 1 insertion(+), 6 deletions(-)
diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
index 5a957a9a0984..8ad576ecd0f1 100644
--- a/arch/arm/xen/enlighten.c
+++ b/arch/arm/xen/enlighten.c
@@ -370,8 +370,6 @@ static int __init xen_guest_init(void)
return -ENOMEM;
}
gnttab_init();
- if (!xen_initial_domain())
- xenbus_probe();
/*
* Making sure board specific code will not set up ops for
diff --git a/drivers/xen/xenbus/xenbus.h b/drivers/xen/xenbus/xenbus.h
index dc1537335414..2a93b7c9c159 100644
--- a/drivers/xen/xenbus/xenbus.h
+++ b/drivers/xen/xenbus/xenbus.h
@@ -115,7 +115,6 @@ int xenbus_probe_node(struct xen_bus_type *bus,
const char *type,
const char *nodename);
int xenbus_probe_devices(struct xen_bus_type *bus);
-void xenbus_probe(void);
void xenbus_dev_changed(const char *node, struct xen_bus_type *bus);
diff --git a/drivers/xen/xenbus/xenbus_probe.c b/drivers/xen/xenbus/xenbus_probe.c
index 18ffd0551b54..8a75092bb148 100644
--- a/drivers/xen/xenbus/xenbus_probe.c
+++ b/drivers/xen/xenbus/xenbus_probe.c
@@ -683,7 +683,7 @@ void unregister_xenstore_notifier(struct notifier_block *nb)
}
EXPORT_SYMBOL_GPL(unregister_xenstore_notifier);
-void xenbus_probe(void)
+static void xenbus_probe(void)
{
xenstored_ready = 1;
diff --git a/include/xen/xenbus.h b/include/xen/xenbus.h
index 2c43b0ef1e4d..bf3cfc7c35d0 100644
--- a/include/xen/xenbus.h
+++ b/include/xen/xenbus.h
@@ -192,8 +192,6 @@ void xs_suspend_cancel(void);
struct work_struct;
-void xenbus_probe(void);
-
#define XENBUS_IS_ERR_READ(str) ({ \
if (!IS_ERR(str) && strlen(str) == 0) { \
kfree(str); \
--
2.17.1
On Wed, 2021-02-10 at 17:06 +0000, Julien Grall wrote:
> From: Julien Grall <[email protected]>
>
> After Commit 3499ba8198cad ("xen: Fix event channel callback via
> INTX/GSI"), xenbus_probe() will be called too early on Arm. This will
> recent to a guest hang during boot.
>
> If there hang wasn't there, we would have ended up to call
> xenbus_probe() twice (the second time is in xenbus_probe_initcall()).
>
> We don't need to initialize xenbus_probe() early for Arm guest.
> Therefore, the call in xen_guest_init() is now removed.
>
> After this change, there is no more external caller for xenbus_probe().
> So the function is turned to a static one. Interestingly there were two
> prototypes for it.
>
> Fixes: 3499ba8198cad ("xen: Fix event channel callback via INTX/GSI")
> Reported-by: Ian Jackson <[email protected]>
> Signed-off-by: Julien Grall <[email protected]>
Reviewed-by: David Woodhouse <[email protected]>
Cc: [email protected]
Amazon Development Centre (London) Ltd. Registered in England and Wales with registration number 04543232 with its registered office at 1 Principal Place, Worship Street, London EC2A 2FA, United Kingdom.
On Wed, 10 Feb 2021, Woodhouse, David wrote:
> On Wed, 2021-02-10 at 17:06 +0000, Julien Grall wrote:
> > From: Julien Grall <[email protected]>
> >
> > After Commit 3499ba8198cad ("xen: Fix event channel callback via
> > INTX/GSI"), xenbus_probe() will be called too early on Arm. This will
> > recent to a guest hang during boot.
> >
> > If there hang wasn't there, we would have ended up to call
> > xenbus_probe() twice (the second time is in xenbus_probe_initcall()).
> >
> > We don't need to initialize xenbus_probe() early for Arm guest.
> > Therefore, the call in xen_guest_init() is now removed.
> >
> > After this change, there is no more external caller for xenbus_probe().
> > So the function is turned to a static one. Interestingly there were two
> > prototypes for it.
> >
> > Fixes: 3499ba8198cad ("xen: Fix event channel callback via INTX/GSI")
> > Reported-by: Ian Jackson <[email protected]>
> > Signed-off-by: Julien Grall <[email protected]>
>
> Reviewed-by: David Woodhouse <[email protected]>
> Cc: [email protected]
Reviewed-by: Stefano Stabellini <[email protected]>
On 10.02.21 18:06, Julien Grall wrote:
> From: Julien Grall <[email protected]>
>
> After Commit 3499ba8198cad ("xen: Fix event channel callback via
> INTX/GSI"), xenbus_probe() will be called too early on Arm. This will
> recent to a guest hang during boot.
>
> If there hang wasn't there, we would have ended up to call
> xenbus_probe() twice (the second time is in xenbus_probe_initcall()).
>
> We don't need to initialize xenbus_probe() early for Arm guest.
> Therefore, the call in xen_guest_init() is now removed.
>
> After this change, there is no more external caller for xenbus_probe().
> So the function is turned to a static one. Interestingly there were two
> prototypes for it.
>
> Fixes: 3499ba8198cad ("xen: Fix event channel callback via INTX/GSI")
> Reported-by: Ian Jackson <[email protected]>
> Signed-off-by: Julien Grall <[email protected]>
Pushed to xen/tip.git for-linus-5.11
Juergen