[PATCH] x86/hpet: fix NULL pointer deference in msi_domain_alloc_irqs()

From: Sergey Senozhatsky
Date: Mon May 11 2015 - 05:56:49 EST


Fix the following oops:
hpet_msi_get_hwirq+0x1f/0x27
msi_domain_alloc+0x35/0xfe
? trace_hardirqs_on_caller+0x16c/0x188
irq_domain_alloc_irqs_recursive+0x51/0x95
__irq_domain_alloc_irqs+0x151/0x223
hpet_assign_irq+0x5d/0x68
hpet_msi_capability_lookup+0x121/0x1cb
? hpet_enable+0x2b4/0x2b4
hpet_late_init+0x5f/0xf2
? hpet_enable+0x2b4/0x2b4
do_one_initcall+0x184/0x199
kernel_init_freeable+0x1af/0x237
? rest_init+0x13a/0x13a
kernel_init+0xe/0xd4
ret_from_fork+0x3f/0x70
? rest_init+0x13a/0x13a

since 3cb96f0c9733 ('x86/hpet: Enhance HPET IRQ to support hierarchical
irqdomains') hpet_msi_capability_lookup() uses hpet_assign_irq(). the
latter discards `irq_alloc_info info' param and instead passes NULL to
__irq_domain_alloc_irqs() as `arg'. __irq_domain_alloc_irqs() invokes
irq_domain_alloc_irqs_recursive(), which msi_domain_alloc_irqs() and,
eventually, accesses `arg->hpet_index' in hpet_msi_get_hwirq().

pass a correct `irq_alloc_info info' pointer to irq_domain_alloc_irqs()
in hpet_assign_irq() to fix the oops.

Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
---
arch/x86/kernel/apic/msi.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/apic/msi.c b/arch/x86/kernel/apic/msi.c
index 58fde66..ef516af 100644
--- a/arch/x86/kernel/apic/msi.c
+++ b/arch/x86/kernel/apic/msi.c
@@ -351,6 +351,6 @@ int hpet_assign_irq(struct irq_domain *domain, struct hpet_dev *dev,
info.hpet_id = hpet_dev_id(domain);
info.hpet_index = dev_num;

- return irq_domain_alloc_irqs(domain, 1, NUMA_NO_NODE, NULL);
+ return irq_domain_alloc_irqs(domain, 1, NUMA_NO_NODE, &info);
}
#endif
--
2.4.0.rc3.3.g6eb1401

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