linux/arch/powerpc/kernel/firmware.c
Nathan Lynch 56537faf88 powerpc: fix unbalanced node refcount in check_kvm_guest()
When check_kvm_guest() succeeds in looking up a /hypervisor OF node, it
returns without performing a matching put for the lookup, leaving the
node's reference count elevated.

Add the necessary call to of_node_put(), rearranging the code slightly to
avoid repetition or goto.

Fixes: 107c55005f ("powerpc/pseries: Add KVM guest doorbell restrictions")
Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Reviewed-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Reviewed-by: Tyrel Datwyler <tyreld@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210928124550.132020-1-nathanl@linux.ibm.com
2021-10-09 00:15:59 +11:00

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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Extracted from cputable.c
*
* Copyright (C) 2001 Ben. Herrenschmidt (benh@kernel.crashing.org)
*
* Modifications for ppc64:
* Copyright (C) 2003 Dave Engebretsen <engebret@us.ibm.com>
* Copyright (C) 2005 Stephen Rothwell, IBM Corporation
*/
#include <linux/export.h>
#include <linux/cache.h>
#include <linux/of.h>
#include <asm/firmware.h>
#include <asm/kvm_guest.h>
#ifdef CONFIG_PPC64
unsigned long powerpc_firmware_features __read_mostly;
EXPORT_SYMBOL_GPL(powerpc_firmware_features);
#endif
#if defined(CONFIG_PPC_PSERIES) || defined(CONFIG_KVM_GUEST)
DEFINE_STATIC_KEY_FALSE(kvm_guest);
int __init check_kvm_guest(void)
{
struct device_node *hyper_node;
hyper_node = of_find_node_by_path("/hypervisor");
if (!hyper_node)
return 0;
if (of_device_is_compatible(hyper_node, "linux,kvm"))
static_branch_enable(&kvm_guest);
of_node_put(hyper_node);
return 0;
}
core_initcall(check_kvm_guest); // before kvm_guest_init()
#endif