[PATCH] x86: kernel: acpi: fix an invalid argument passing in io_apic.c

[Seunghun Han]

I'm Seunghun Han, and I work for National Security Research Institute of
South Korea.

I found a kernel panic while I tested latest kernel version.

The kernel panic log is as follows:
>[    0.058851] BUG: unable to handle kernel NULL pointer dereference at 0000000000000010
>[    0.060000] IP: io_apic_modify_irq+0x11/0x80
>[    0.060000] PGD 0
>[    0.060000] P4D 0
>[    0.060000]
>[    0.060000] Oops: 0000 [#1] SMP
>[    0.060000] Modules linked in:
>[    0.060000] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.12.0-rc5 #26
>[    0.060000] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006
>[    0.060000] task: ffff88021619acc0 task.stack: ffffc90000c50000
>[    0.060000] RIP: 0010:io_apic_modify_irq+0x11/0x80
>[    0.060000] RSP: 0000:ffffc90000c53e40 EFLAGS: 00010046
>[    0.060000] RAX: 0000000000000082 RBX: 0000000000000000 RCX: 0000000000000000
>[    0.060000] RDX: 0000000000000000 RSI: 00000000fffeffff RDI: 0000000000000000
>[    0.060000] RBP: 0000000000000000 R08: ffff8802170cda00 R09: 0000000000000117
>[    0.060000] R10: 0000000000000000 R11: 0000000000000116 R12: 0000000000000000
>[    0.060000] R13: 0000000000000000 R14: ffff8802170cda58 R15: ffff8802170cec00
>[    0.060000] FS:  0000000000000000(0000) GS:ffff88021fc00000(0000) knlGS:0000000000000000
>[    0.060000] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>[    0.060000] CR2: 0000000000000010 CR3: 0000000001a09000 CR4: 00000000000006f0
>[    0.060000] Call Trace:
>[    0.060000]  ? unmask_ioapic_irq+0x2b/0x40
>[    0.060000]  ? setup_IO_APIC+0x79b/0x7a3
>[    0.060000]  ? clear_IO_APIC_pin+0x93/0x130
>[    0.060000]  ? apic_bsp_setup+0xa2/0xac
>[    0.060000]  ? native_smp_prepare_cpus+0x245/0x2b1
>[    0.060000]  ? kernel_init_freeable+0xd0/0x21f
>[    0.060000]  ? rest_init+0x80/0x80
>[    0.060000]  ? kernel_init+0xa/0x100
>[    0.060000]  ? ret_from_fork+0x25/0x30
>[    0.060000] Code: 47 04 83 c6 10 25 ff 0f 00 00 48 2d 00 10 80 00 48 29 c8 89 30 89 50 10 c3 90 0f 1f 44 00 00 41 55 41 54 49 89 cd 55 53 48 89 fb <23> 77 10 09 d6 89 73 10 4c 8b 27 89 f5 4c 39 e7 74 4f 41 8b 44
>[    0.060000] RIP: io_apic_modify_irq+0x11/0x80 RSP: ffffc90000c53e40
>[    0.060000] CR2: 0000000000000010
>[    0.060000] ---[ end trace c0d793cf886c6f59 ]---
>[    0.060000] Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000009
>[    0.060000]
>[    0.060000] ---[ end Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000009
>[    0.060000]

I analyzed this kernel panic in detail and found that check_timer() function
passed an invalid argument to unmask_ioapic_irq() function.

The code is as follows:
>	int idx;
>	idx = find_irq_entry(apic1, pin1, mp_INT);
>	if (idx != -1 && irq_trigger(idx))
>		unmask_ioapic_irq(irq_get_chip_data(0));

The unmask_ioapic_irq() function wants a "struct irq_data *" argument, but
the code, irq_get_chip_data(0), passes a "struct irq_chip *" value.

To fix an invalid argument passing, I made a patch which passes a return
value of irq_get_irq_data(0).

Thank you.

Signed-off-by: Seunghun Han <kkamagui@xxxxxxxxx>
---
 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 b4f5f73..237e9c2 100644
--- 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);
-- 
2.1.4