x86/ioapic: Pass the correct data to unmask_ioapic_irq()

One of the rarely executed code pathes in check_timer() calls
unmask_ioapic_irq() passing irq_get_chip_data(0) as argument.

That's wrong as unmask_ioapic_irq() expects a pointer to the irq data of
interrupt 0. irq_get_chip_data(0) returns NULL, so the following
dereference in unmask_ioapic_irq() causes a kernel panic.

The issue went unnoticed in the first place because irq_get_chip_data()
returns a void pointer so the compiler cannot do a type check on the
argument. The code path was added for machines with broken configuration,
but it seems that those machines are either not running current kernels or
simply do not longer exist.

Hand in irq_get_irq_data(0) as argument which provides the correct data.

[ tglx: Rewrote changelog ]

Fixes: 943e15e936c0 ("x86/irq: Move irq_cfg.irq_2_pin into io_apic.c")
Signed-off-by: Seunghun Han <kkamagui@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1500369644-45767-1-git-send-email-kkamagui@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
index b4f5f73febdb8c2ac3b64f3964027869b80cc835..237e9c2341c71eef924296d3d425c9cd4e95f447 100644 (file)
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -2093,7 +2093,7 @@ static inline void __init check_timer(void)
                        int idx;
                        idx = find_irq_entry(apic1, pin1, mp_INT);
                        if (idx != -1 && irq_trigger(idx))
-                               unmask_ioapic_irq(irq_get_chip_data(0));
+                               unmask_ioapic_irq(irq_get_irq_data(0));
                }
                irq_domain_deactivate_irq(irq_data);
                irq_domain_activate_irq(irq_data);