[Bionic][PATCH v3 02/21] genirq/affinity: Don't return with empty affinity masks on error

[Jose Ricardo Ziviani]

From: Thomas Gleixner <tglx at linutronix.de>

BugLink: http://bugs.launchpad.net/bugs/1759723

When the allocation of node_to_possible_cpumask fails, then
irq_create_affinity_masks() returns with a pointer to the empty affinity
masks array, which will cause malfunction.

Reorder the allocations so the masks array allocation comes last and every
failure path returns NULL.

Fixes: 9a0ef98e186d ("genirq/affinity: Assign vectors to all present CPUs")
Signed-off-by: Thomas Gleixner <tglx at linutronix.de>
Cc: Christoph Hellwig <hch at infradead.org>
Cc: Ming Lei <ming.lei at redhat.com>
(cherry picked from commit 0211e12dd0a5385ecffd3557bc570dbad7fcf245)
Signed-off-by: Jose Ricardo Ziviani <joserz at linux.ibm.com>
---
 kernel/irq/affinity.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/kernel/irq/affinity.c b/kernel/irq/affinity.c
index a37a3b4b6342..e0665549af59 100644
--- a/kernel/irq/affinity.c
+++ b/kernel/irq/affinity.c
@@ -108,7 +108,7 @@ irq_create_affinity_masks(int nvecs, const struct irq_affinity *affd)
 	int affv = nvecs - affd->pre_vectors - affd->post_vectors;
 	int last_affv = affv + affd->pre_vectors;
 	nodemask_t nodemsk = NODE_MASK_NONE;
-	struct cpumask *masks;
+	struct cpumask *masks = NULL;
 	cpumask_var_t nmsk, *node_to_possible_cpumask;
 
 	/*
@@ -121,13 +121,13 @@ irq_create_affinity_masks(int nvecs, const struct irq_affinity *affd)
 	if (!zalloc_cpumask_var(&nmsk, GFP_KERNEL))
 		return NULL;
 
-	masks = kcalloc(nvecs, sizeof(*masks), GFP_KERNEL);
-	if (!masks)
-		goto out;
-
 	node_to_possible_cpumask = alloc_node_to_possible_cpumask();
 	if (!node_to_possible_cpumask)
-		goto out;
+		goto outcpumsk;
+
+	masks = kcalloc(nvecs, sizeof(*masks), GFP_KERNEL);
+	if (!masks)
+		goto outnodemsk;
 
 	/* Fill out vectors at the beginning that don't need affinity */
 	for (curvec = 0; curvec < affd->pre_vectors; curvec++)
@@ -192,8 +192,9 @@ irq_create_affinity_masks(int nvecs, const struct irq_affinity *affd)
 	/* Fill out vectors at the end that don't need affinity */
 	for (; curvec < nvecs; curvec++)
 		cpumask_copy(masks + curvec, irq_default_affinity);
+outnodemsk:
 	free_node_to_possible_cpumask(node_to_possible_cpumask);
-out:
+outcpumsk:
 	free_cpumask_var(nmsk);
 	return masks;
 }
-- 
2.17.0