FAILED: patch "[PATCH] x86/apic/vector: Fix off by one in error path" failed to apply to 4.9-stable tree

The patch below does not apply to the 4.9-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From: Thomas Gleixner <[email protected]>
Date: Tue, 16 Jan 2018 12:20:18 +0100
Subject: [PATCH] x86/apic/vector: Fix off by one in error path

Keith reported the following warning:

WARNING: CPU: 28 PID: 1420 at kernel/irq/matrix.c:222 irq_matrix_remove_managed+0x10f/0x120
  x86_vector_free_irqs+0xa1/0x180
  x86_vector_alloc_irqs+0x1e4/0x3a0
  msi_domain_alloc+0x62/0x130

The reason for this is that if the vector allocation fails the error handling code tries to free the failed vector as well, which causes the above imbalance warning to trigger.

Adjust the error path to handle this correctly.

index f8b03bb8e725..3cc471beb50b 100644
@@ -542,14 +542,17 @@ static int x86_vector_alloc_irqs(struct irq_domain *domain, unsigned int virq,
 
 		err = assign_irq_vector_policy(irqd, info);
 		trace_vector_setup(virq + i, false, err);
-		if (err)
+		if (err) {
+			irqd->chip_data = NULL;
+			free_apic_chip_data(apicd);
 			goto error;
+		}
 	}
 
 	return 0;
 
 error:
-	x86_vector_free_irqs(domain, virq, i + 1);
+	x86_vector_free_irqs(domain, virq, i);
 	return err;
 }