linux-kernel - [PATCH hyperv-next v5 09/16] Drivers: hv: Check message and event pages for non-NULL before iounmap()

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Message-ID: <20250828010557.123869-10-romank@linux.microsoft.com>
Date: Wed, 27 Aug 2025 18:05:50 -0700
From: Roman Kisel <romank@...ux.microsoft.com>
To: arnd@...db.de,
	bp@...en8.de,
	corbet@....net,
	dave.hansen@...ux.intel.com,
	decui@...rosoft.com,
	haiyangz@...rosoft.com,
	hpa@...or.com,
	kys@...rosoft.com,
	mikelley@...rosoft.com,
	mingo@...hat.com,
	tglx@...utronix.de,
	Tianyu.Lan@...rosoft.com,
	wei.liu@...nel.org,
	x86@...nel.org,
	linux-hyperv@...r.kernel.org,
	linux-doc@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	linux-arch@...r.kernel.org
Cc: benhill@...rosoft.com,
	bperkins@...rosoft.com,
	sunilmut@...rosoft.com,
	romank@...ux.microsoft.com
Subject: [PATCH hyperv-next v5 09/16] Drivers: hv: Check message and event pages for non-NULL before iounmap()

It might happen that some hyp SynIC pages aren't allocated.

Check for that and only then call iounmap().

Signed-off-by: Roman Kisel <romank@...ux.microsoft.com>
Reviewed-by: Tianyu Lan <tiala@...rosoft.com>
Reviewed-by: Michael Kelley <mhklinux@...look.com>
---
 drivers/hv/hv.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c
index 1e7fd7c19c58..7c5f35806e77 100644
--- a/drivers/hv/hv.c
+++ b/drivers/hv/hv.c
@@ -372,8 +372,10 @@ void hv_synic_disable_regs(unsigned int cpu)
 	 */
 	simp.simp_enabled = 0;
 	if (ms_hyperv.paravisor_present || hv_root_partition()) {
-		iounmap(hv_cpu->hyp_synic_message_page);
-		hv_cpu->hyp_synic_message_page = NULL;
+		if (hv_cpu->hyp_synic_message_page) {
+			iounmap(hv_cpu->hyp_synic_message_page);
+			hv_cpu->hyp_synic_message_page = NULL;
+		}
 	} else {
 		simp.base_simp_gpa = 0;
 	}
@@ -384,8 +386,10 @@ void hv_synic_disable_regs(unsigned int cpu)
 	siefp.siefp_enabled = 0;
 
 	if (ms_hyperv.paravisor_present || hv_root_partition()) {
-		iounmap(hv_cpu->hyp_synic_event_page);
-		hv_cpu->hyp_synic_event_page = NULL;
+		if (hv_cpu->hyp_synic_event_page) {
+			iounmap(hv_cpu->hyp_synic_event_page);
+			hv_cpu->hyp_synic_event_page = NULL;
+		}
 	} else {
 		siefp.base_siefp_gpa = 0;
 	}
-- 
2.43.0