From 52ad57a9b68e215c4f5fa2cfd2412132b522bff5 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Philippe=20Mathieu-Daud=C3=A9?= Date: Thu, 18 Mar 2021 17:30:59 +0100 Subject: [PATCH] hw/intc/i8259: Refactor pic_read_irq() to avoid uninitialized variable MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Some compiler versions are smart enough to detect a potentially uninitialized variable, but are not smart enough to detect that this cannot happen due to the code flow: ../hw/intc/i8259.c: In function ‘pic_read_irq’: ../hw/intc/i8259.c:203:13: error: ‘irq2’ may be used uninitialized in this function [-Werror=maybe-uninitialized] 203 | irq = irq2 + 8; | ~~~~^~~~~~~~~~ Restrict irq2 variable use to the inner statement. Fixes: 78ef2b6989f ("i8259: Reorder intack in pic_read_irq") Reported-by: Christian Borntraeger Signed-off-by: Philippe Mathieu-Daudé Message-Id: <20210318163059.3686596-1-philmd@redhat.com> Signed-off-by: Paolo Bonzini --- hw/intc/i8259.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/hw/intc/i8259.c b/hw/intc/i8259.c index 344fd04db1..cc4e21ffec 100644 --- a/hw/intc/i8259.c +++ b/hw/intc/i8259.c @@ -176,10 +176,12 @@ static void pic_intack(PICCommonState *s, int irq) int pic_read_irq(DeviceState *d) { PICCommonState *s = PIC_COMMON(d); - int irq, irq2, intno; + int irq, intno; irq = pic_get_irq(s); if (irq >= 0) { + int irq2; + if (irq == 2) { irq2 = pic_get_irq(slave_pic); if (irq2 >= 0) { @@ -189,20 +191,18 @@ int pic_read_irq(DeviceState *d) irq2 = 7; } intno = slave_pic->irq_base + irq2; + pic_intack(s, irq); + irq = irq2 + 8; } else { intno = s->irq_base + irq; + pic_intack(s, irq); } - pic_intack(s, irq); } else { /* spurious IRQ on host controller */ irq = 7; intno = s->irq_base + irq; } - if (irq == 2) { - irq = irq2 + 8; - } - #ifdef DEBUG_IRQ_LATENCY printf("IRQ%d latency=%0.3fus\n", irq, -- 2.11.4.GIT