From 8886196a73204d167b7f8797eb6ebf61e76794d6 Mon Sep 17 00:00:00 2001 From: "Liam R. Howlett" Date: Tue, 23 May 2017 21:54:11 -0400 Subject: [PATCH] sparc64: Zero pages on allocation for mondo and error queues. [ Upstream commit 7a7dc961a28b965a0d0303c2e989df17b411708b ] Error queues use a non-zero first word to detect if the queues are full. Using pages that have not been zeroed may result in false positive overflow events. These queues are set up once during boot so zeroing all mondo and error queue pages is safe. Note that the false positive overflow does not always occur because the page allocation for these queues is so early in the boot cycle that higher number CPUs get fresh pages. It is only when traps are serviced with lower number CPUs who were given already used pages that this issue is exposed. Signed-off-by: Liam R. Howlett Signed-off-by: David S. Miller Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- arch/sparc/kernel/irq_64.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/sparc/kernel/irq_64.c b/arch/sparc/kernel/irq_64.c index e1b1ce63a328..5cbf03c14981 100644 --- a/arch/sparc/kernel/irq_64.c +++ b/arch/sparc/kernel/irq_64.c @@ -1021,7 +1021,7 @@ static void __init alloc_one_queue(unsigned long *pa_ptr, unsigned long qmask) unsigned long order = get_order(size); unsigned long p; - p = __get_free_pages(GFP_KERNEL, order); + p = __get_free_pages(GFP_KERNEL | __GFP_ZERO, order); if (!p) { prom_printf("SUN4V: Error, cannot allocate queue.\n"); prom_halt();