From 75b0f71b26b3ad833c5c0670109c0af6e021e86a Mon Sep 17 00:00:00 2001 From: Weichen Chen Date: Fri, 24 Feb 2023 10:36:32 +0800 Subject: [PATCH] pstore/ram: Fix crash when setting number of cpus to an odd number [ Upstream commit d49270a04623ce3c0afddbf3e984cb245aa48e9c ] When the number of cpu cores is adjusted to 7 or other odd numbers, the zone size will become an odd number. The address of the zone will become: addr of zone0 = BASE addr of zone1 = BASE + zone_size addr of zone2 = BASE + zone_size*2 ... The address of zone1/3/5/7 will be mapped to non-alignment va. Eventually crashes will occur when accessing these va. So, use ALIGN_DOWN() to make sure the zone size is even to avoid this bug. Signed-off-by: Weichen Chen Reviewed-by: Matthias Brugger Tested-by: "Guilherme G. Piccoli" Link: https://lore.kernel.org/r/20230224023632.6840-1-weichen.chen@mediatek.com Signed-off-by: Kees Cook Signed-off-by: Sasha Levin --- fs/pstore/ram.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c index f3fa3625d772..e15b4631364a 100644 --- a/fs/pstore/ram.c +++ b/fs/pstore/ram.c @@ -519,6 +519,7 @@ static int ramoops_init_przs(const char *name, } zone_sz = mem_sz / *cnt; + zone_sz = ALIGN_DOWN(zone_sz, 2); if (!zone_sz) { dev_err(dev, "%s zone size == 0\n", name); goto fail;