linux-kernel - [PATCH AUTOSEL 4.18 031/131] Drivers: hv: vmbus: Cleanup synic memory free path

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Date:   Sun, 2 Sep 2018 13:03:36 +0000
From:   Sasha Levin <Alexander.Levin@...rosoft.com>
To:     "stable@...r.kernel.org" <stable@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC:     "Michael Kelley (EOSG)" <Michael.H.Kelley@...rosoft.com>,
        KY Srinivasan <kys@...rosoft.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Sasha Levin <Alexander.Levin@...rosoft.com>
Subject: [PATCH AUTOSEL 4.18 031/131] Drivers: hv: vmbus: Cleanup synic memory
 free path

From: Michael Kelley <mikelley@...rosoft.com>

[ Upstream commit 572086325ce9a9e348b8748e830653f3959e88b6 ]

clk_evt memory is not being freed when the synic is shutdown
or when there is an allocation error.  Add the appropriate
kfree() call, along with a comment to clarify how the memory
gets freed after an allocation error.  Make the free path
consistent by removing checks for NULL since kfree() and
free_page() already do the check.

Signed-off-by: Michael Kelley <mikelley@...rosoft.com>
Reported-by: Dan Carpenter <dan.carpenter@...cle.com>
Signed-off-by: K. Y. Srinivasan <kys@...rosoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Signed-off-by: Sasha Levin <alexander.levin@...rosoft.com>
---
 drivers/hv/hv.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c
index 658dc765753b..553adccb05d7 100644
--- a/drivers/hv/hv.c
+++ b/drivers/hv/hv.c
@@ -242,6 +242,10 @@ int hv_synic_alloc(void)
 
 	return 0;
 err:
+	/*
+	 * Any memory allocations that succeeded will be freed when
+	 * the caller cleans up by calling hv_synic_free()
+	 */
 	return -ENOMEM;
 }
 
@@ -254,12 +258,10 @@ void hv_synic_free(void)
 		struct hv_per_cpu_context *hv_cpu
 			= per_cpu_ptr(hv_context.cpu_context, cpu);
 
-		if (hv_cpu->synic_event_page)
-			free_page((unsigned long)hv_cpu->synic_event_page);
-		if (hv_cpu->synic_message_page)
-			free_page((unsigned long)hv_cpu->synic_message_page);
-		if (hv_cpu->post_msg_page)
-			free_page((unsigned long)hv_cpu->post_msg_page);
+		kfree(hv_cpu->clk_evt);
+		free_page((unsigned long)hv_cpu->synic_event_page);
+		free_page((unsigned long)hv_cpu->synic_message_page);
+		free_page((unsigned long)hv_cpu->post_msg_page);
 	}
 
 	kfree(hv_context.hv_numa_map);
-- 
2.17.1