linux-kernel - [PATCH 3.12 34/60] hv: allocate synic pages for all present CPUs

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Date:   Tue, 14 Mar 2017 14:15:25 +0100
From:   Jiri Slaby <jslaby@...e.cz>
To:     stable@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        "K . Y . Srinivasan" <kys@...rosoft.com>,
        Jiri Slaby <jslaby@...e.cz>
Subject: [PATCH 3.12 34/60] hv: allocate synic pages for all present CPUs

From: Vitaly Kuznetsov <vkuznets@...hat.com>

3.12-stable review patch.  If anyone has any objections, please let me know.

===============

commit 421b8f20d3c381b215f988b42428f56fc3b82405 upstream.

It may happen that not all CPUs are online when we do hv_synic_alloc() and
in case more CPUs come online later we may try accessing these allocated
structures.

Signed-off-by: Vitaly Kuznetsov <vkuznets@...hat.com>
Signed-off-by: K. Y. Srinivasan <kys@...rosoft.com>
Signed-off-by: Jiri Slaby <jslaby@...e.cz>
---
 drivers/hv/hv.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c
index 88f4096fa078..3fdb9af08705 100644
--- a/drivers/hv/hv.c
+++ b/drivers/hv/hv.c
@@ -271,7 +271,7 @@ int hv_synic_alloc(void)
 	size_t size = sizeof(struct tasklet_struct);
 	int cpu;
 
-	for_each_online_cpu(cpu) {
+	for_each_present_cpu(cpu) {
 		hv_context.event_dpc[cpu] = kmalloc(size, GFP_ATOMIC);
 		if (hv_context.event_dpc[cpu] == NULL) {
 			pr_err("Unable to allocate event dpc\n");
@@ -314,7 +314,7 @@ void hv_synic_free(void)
 {
 	int cpu;
 
-	for_each_online_cpu(cpu)
+	for_each_present_cpu(cpu)
 		hv_synic_free_cpu(cpu);
 }
 
-- 
2.12.0