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From:   Norbert Manthey <nmanthey@amazon.de>
To:     Norbert Manthey <nmanthey@amazon.de>,
        <linux-kernel@vger.kernel.org>
CC:     David Woodhouse <dwmw@amazon.co.uk>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        "H. Peter Anvin" <hpa@zytor.com>, <x86@kernel.org>,
        "Eric W. Biederman" <ebiederm@xmission.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        "Mike Rapoport" <rppt@linux.vnet.ibm.com>,
        Baoquan He <bhe@redhat.com>,
        "Nicolai Stange" <nstange@suse.de>,
        Jan Beulich <JBeulich@suse.com>,
        Jan Kiszka <jan.kiszka@siemens.com>
Subject: [PATCH] io_apic: initialize irq with -EINVAL
Date:   Wed, 28 Nov 2018 12:09:51 +0100
Message-ID: <1543403393-6004-1-git-send-email-nmanthey@amazon.de>
MIME-Version: 1.0
Content-Type: text/plain
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

To catch the case where the uninitialized variable irq might be
returned. As the path that might lead to this situation can only
occur based on invalid arguments, we initialize this variable with
the value -EINVAL, so that callers are notified accordingly, and no
uninitialized value is returned.

The path that would allow to return an uninitialized value for the
variable irq would require legacy IRQs without the ALLOC flag.

Signed-off-by: Norbert Manthey <nmanthey@amazon.de>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
---
 arch/x86/kernel/apic/io_apic.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
index 2953bbf..219dbc1 100644
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -1031,7 +1031,7 @@ static int alloc_isa_irq_from_domain(struct irq_domain *domain,
 static int mp_map_pin_to_irq(u32 gsi, int idx, int ioapic, int pin,
 			     unsigned int flags, struct irq_alloc_info *info)
 {
-	int irq;
+	int irq = -EINVAL;
 	bool legacy = false;
 	struct irq_alloc_info tmp;
 	struct mp_chip_data *data;
-- 
2.7.4


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