[Xen-devel] [PATCH v1 2/2] xen/arm: Fix deadlock in on_selected_cpus function

[Oleksandr Tyshchenko <oleksandr.tyshchenko@xxxxxxxxxxxxxxx>]

This patch is needed to avoid possible deadlocks in case of simultaneous
occurrence cross-interrupts.

Change-Id: I574b496442253a7b67a27e2edd793526c8131284
Signed-off-by: Oleksandr Tyshchenko <oleksandr.tyshchenko@xxxxxxxxxxxxxxx>
Signed-off-by: Andrii Tseglytskyi <andrii.tseglytskyi@xxxxxxxxxxxxxxx>
---
 xen/common/smp.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/xen/common/smp.c b/xen/common/smp.c
index 2700bd7..46d2fc6 100644
--- a/xen/common/smp.c
+++ b/xen/common/smp.c
@@ -55,7 +55,11 @@ void on_selected_cpus(
 
     ASSERT(local_irq_is_enabled());
 
-    spin_lock(&call_lock);
+    if (!spin_trylock(&call_lock)) {
+        if (smp_call_function_interrupt())
+            return;
+        spin_lock(&call_lock);
+    }
 
     cpumask_copy(&call_data.selected, selected);
 
-- 
1.7.9.5


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