From 0e39751e82e35674eca062653e95bf40f7b2c614 Mon Sep 17 00:00:00 2001
From: Cong Wang <xiyou.wangcong@gmail.com>
Date: Wed, 11 Sep 2019 17:14:21 -0700
Subject: [PATCH] xfrm: handle percpu allocation failure gracefully

Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
---
 net/xfrm/xfrm_ipcomp.c | 42 +++++++++++++++++++++++++++++++++---------
 1 file changed, 33 insertions(+), 9 deletions(-)

diff --git a/net/xfrm/xfrm_ipcomp.c b/net/xfrm/xfrm_ipcomp.c
index 32c364d3bfb3f3..5e9c938d9b9f4d 100644
--- a/net/xfrm/xfrm_ipcomp.c
+++ b/net/xfrm/xfrm_ipcomp.c
@@ -217,7 +217,7 @@ static void ipcomp_free_scratches(void)
 static void * __percpu *ipcomp_alloc_scratches(void)
 {
 	void * __percpu *scratches;
-	int i;
+	int i, failed_cpu;
 
 	if (ipcomp_scratch_users++)
 		return ipcomp_scratches;
@@ -232,12 +232,24 @@ static void * __percpu *ipcomp_alloc_scratches(void)
 		void *scratch;
 
 		scratch = vmalloc_node(IPCOMP_SCRATCH_SIZE, cpu_to_node(i));
-		if (!scratch)
-			return NULL;
+		if (!scratch) {
+			failed_cpu = i;
+			goto fail;
+		}
 		*per_cpu_ptr(scratches, i) = scratch;
 	}
 
 	return scratches;
+
+fail:
+	for_each_possible_cpu(i) {
+		if (i == failed_cpu)
+			break;
+		vfree(*per_cpu_ptr(scratches, i));
+	}
+	ipcomp_scratches = NULL;
+	free_percpu(scratches);
+	return NULL;
 }
 
 static void ipcomp_free_tfms(struct crypto_comp * __percpu *tfms)
@@ -272,7 +284,7 @@ static struct crypto_comp * __percpu *ipcomp_alloc_tfms(const char *alg_name)
 {
 	struct ipcomp_tfms *pos;
 	struct crypto_comp * __percpu *tfms;
-	int cpu;
+	int cpu, failed_cpu;
 
 
 	list_for_each_entry(pos, &ipcomp_tfms_list, list) {
@@ -297,20 +309,32 @@ static struct crypto_comp * __percpu *ipcomp_alloc_tfms(const char *alg_name)
 
 	pos->tfms = tfms = alloc_percpu(struct crypto_comp *);
 	if (!tfms)
-		goto error;
+		goto err_list_del;
 
 	for_each_possible_cpu(cpu) {
 		struct crypto_comp *tfm = crypto_alloc_comp(alg_name, 0,
 							    CRYPTO_ALG_ASYNC);
-		if (IS_ERR(tfm))
-			goto error;
+		if (IS_ERR(tfm)) {
+			failed_cpu = cpu;
+			goto err_free;
+		}
 		*per_cpu_ptr(tfms, cpu) = tfm;
 	}
 
 	return tfms;
 
-error:
-	ipcomp_free_tfms(tfms);
+err_free:
+	for_each_possible_cpu(cpu) {
+		struct crypto_comp *tfm = *per_cpu_ptr(tfms, cpu);
+
+		if (cpu == failed_cpu)
+			break;
+		crypto_free_comp(tfm);
+	}
+	free_percpu(tfms);
+err_list_del:
+	list_del(&pos->list);
+	kfree(pos);
 	return NULL;
 }