From: Liam R. Howlett Date: Tue, 17 Jan 2017 15:59:02 +0000 (-0500) Subject: sparc64: Zero pages on allocation for mondo and error queues. X-Git-Tag: v4.14-rc1~1618^2^2~1 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=7a7dc961a28b965a0d0303c2e989df17b411708b;p=platform%2Fkernel%2Flinux-rpi3.git sparc64: Zero pages on allocation for mondo and error queues. 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 --- diff --git a/arch/sparc/kernel/irq_64.c b/arch/sparc/kernel/irq_64.c index 34a7930..baed4cd 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();