From 5b7526e3a640e491075557acaa842c59c652c0c3 Mon Sep 17 00:00:00 2001 From: David Daney Date: Thu, 5 Apr 2012 16:52:13 -0700 Subject: [PATCH] irq/irq_domain: Quit ignoring error returns from irq_alloc_desc_from(). In commit 4bbdd45a (irq_domain/powerpc: eliminate irq_map; use irq_alloc_desc() instead) code was added that ignores error returns from irq_alloc_desc_from() by (silently) casting the return value to unsigned. The negitive value error return now suddenly looks like a valid irq number. Commits cc79ca69 (irq_domain: Move irq_domain code from powerpc to kernel/irq) and 1bc04f2c (irq_domain: Add support for base irq and hwirq in legacy mappings) move this code to its current location in irqdomain.c The result of all of this is a null pointer dereference OOPS if one of the error cases is hit. The fix: Don't cast away the negativeness of the return value and then check for errors. Signed-off-by: David Daney Acked-by: Rob Herring [grant.likely: dropped addition of new 'irq' variable] Signed-off-by: Grant Likely --- kernel/irq/irqdomain.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c index 3601f3f..9310a8d 100644 --- a/kernel/irq/irqdomain.c +++ b/kernel/irq/irqdomain.c @@ -350,7 +350,8 @@ unsigned int irq_create_direct_mapping(struct irq_domain *domain) unsigned int irq_create_mapping(struct irq_domain *domain, irq_hw_number_t hwirq) { - unsigned int virq, hint; + unsigned int hint; + int virq; pr_debug("irq: irq_create_mapping(0x%p, 0x%lx)\n", domain, hwirq); @@ -381,9 +382,9 @@ unsigned int irq_create_mapping(struct irq_domain *domain, if (hint == 0) hint++; virq = irq_alloc_desc_from(hint, 0); - if (!virq) + if (virq <= 0) virq = irq_alloc_desc_from(1, 0); - if (!virq) { + if (virq <= 0) { pr_debug("irq: -> virq allocation failed\n"); return 0; } -- 2.7.4