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From:   Xiyu Yang <xiyuyang19@fudan.edu.cn>
To:     Arnd Bergmann <arnd@arndb.de>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Xiyu Yang <xiyuyang19@fudan.edu.cn>,
        Vishnu DASA <vdasa@vmware.com>, Xin Tan <tanxin.ctf@gmail.com>,
        Allison Randal <allison@lohutok.net>,
        Thomas Gleixner <tglx@linutronix.de>,
        linux-kernel@vger.kernel.org
Cc:     yuanxzhang@fudan.edu.cn, kjlu@umn.edu
Subject: [PATCH] VMCI: Fix potential NULL pointer dereference when acquire a lock
Date:   Tue, 17 Mar 2020 00:36:47 +0800
Message-Id: <1584376610-11979-1-git-send-email-xiyuyang19@fudan.edu.cn>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

A NULL pointer can be returned by vmci_ctx_get(). Thus add a
corresponding check so that a NULL pointer dereference will
be avoided when acquire a lock in spin_lock.

Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Signed-off-by: Xin Tan <tanxin.ctf@gmail.com>
---
 drivers/misc/vmw_vmci/vmci_context.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/misc/vmw_vmci/vmci_context.c b/drivers/misc/vmw_vmci/vmci_context.c
index 16695366ec92..a20878fba374 100644
--- a/drivers/misc/vmw_vmci/vmci_context.c
+++ b/drivers/misc/vmw_vmci/vmci_context.c
@@ -898,6 +898,8 @@ void vmci_ctx_rcv_notifications_release(u32 context_id,
 					bool success)
 {
 	struct vmci_ctx *context = vmci_ctx_get(context_id);
+	if (context == NULL)
+		return;
 
 	spin_lock(&context->lock);
 	if (!success) {
-- 
2.7.4