[PATCH] xen: Fix null pointer dereference in xen_init_lock_cpu()

[Ma Ke <make24@iscas.ac.cn>]

kasprintf() is used for formatting strings and dynamically allocating
memory space. If memory allocation fails, kasprintf() will return NULL.
We should add a check to ensure that failure does not occur.

Fixes: d5de8841355a ("x86: split spinlock implementations out into their own files")
Signed-off-by: Ma Ke <make24@iscas.ac.cn>
---
Found this error through static analysis.
---
 arch/x86/xen/spinlock.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/x86/xen/spinlock.c b/arch/x86/xen/spinlock.c
index 5c6fc16e4b92..fe3cd95c1604 100644
--- a/arch/x86/xen/spinlock.c
+++ b/arch/x86/xen/spinlock.c
@@ -75,6 +75,8 @@ void xen_init_lock_cpu(int cpu)
 	     cpu, per_cpu(lock_kicker_irq, cpu));
 
 	name = kasprintf(GFP_KERNEL, "spinlock%d", cpu);
+	if (!name)
+		return;
 	per_cpu(irq_name, cpu) = name;
 	irq = bind_ipi_to_irqhandler(XEN_SPIN_UNLOCK_VECTOR,
 				     cpu,
-- 
2.25.1