From e213e87785559eaf3107897226817aea9291b06f Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Fri, 15 Aug 2008 18:12:47 +0200 Subject: [PATCH] x86: Fix ioremap off by one BUG Jean Delvare's machine triggered this BUG acpi_os_map_memory phys ffff0000 size 65535 ------------[ cut here ]------------ kernel BUG at arch/x86/mm/pat.c:233! with ACPI in the backtrace. Adding some debugging output showed that ACPI calls acpi_os_map_memory phys ffff0000 size 65535 And ioremap/PAT does this check in 32bit, so addr+size wraps and the BUG in reserve_memtype() triggers incorrectly. BUG_ON(start >= end); /* end is exclusive */ But reserve_memtype already uses u64: int reserve_memtype(u64 start, u64 end, so the 32bit truncation must happen in the caller. Presumably in ioremap when it passes this information to reserve_memtype(). This patch does this computation in 64bit. http://bugzilla.kernel.org/show_bug.cgi?id=11346 Signed-off-by: Andi Kleen --- arch/x86/mm/ioremap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c index 016f335bbeea..6ba6f889c79d 100644 --- a/arch/x86/mm/ioremap.c +++ b/arch/x86/mm/ioremap.c @@ -170,7 +170,7 @@ static void __iomem *__ioremap_caller(resource_size_t phys_addr, phys_addr &= PAGE_MASK; size = PAGE_ALIGN(last_addr+1) - phys_addr; - retval = reserve_memtype(phys_addr, phys_addr + size, + retval = reserve_memtype(phys_addr, (u64)phys_addr + size, prot_val, &new_prot_val); if (retval) { pr_debug("Warning: reserve_memtype returned %d\n", retval); -- 2.20.1