Re: [patch] x86/pat: pass correct address to sanitize_phys

From: David Hildenbrand
Date: Mon Aug 09 2021 - 13:25:15 EST

On 21.07.21 21:48, Jeff Moyer wrote:
memtype_reserve takes an address range of the form [start, end). It
then passes the start and end addresses to sanitize_phys, which is meant
to operate on the inclusive addresses. If end falls at the end of the
physical address space, sanitize_phys will return 0. This can result in
drivers failing to load:

[ 10.000087] mpt3sas_cm0: unable to map adapter memory! or resource not found
[ 10.000334] mpt3sas_cm0: failure at drivers/scsi/mpt3sas/mpt3sas_scsih.c:10597/_scsih_probe()!

Fix this by passing the inclusive end address to sanitize_phys.

Fixes: 510ee090abc3 ("x86/mm/pat: Prepare {reserve, free}_memtype() for "decoy" addresses")
Signed-off-by: Jeff Moyer <jmoyer@xxxxxxxxxx>
It might be worth adding a comment, here. If there are any suggestions
on what a sane wording would be, I'm all ears.

diff --git a/arch/x86/mm/pat/memtype.c b/arch/x86/mm/pat/memtype.c
index 3112ca7786ed..482557905294 100644
--- a/arch/x86/mm/pat/memtype.c
+++ b/arch/x86/mm/pat/memtype.c
@@ -583,7 +583,7 @@ int memtype_reserve(u64 start, u64 end, enum page_cache_mode req_type,
int err = 0;
start = sanitize_phys(start);
- end = sanitize_phys(end);
+ end = sanitize_phys(end - 1) + 1;
if (start >= end) {
WARN(1, "%s failed: [mem %#010Lx-%#010Lx], req %s\n", __func__,
start, end - 1, cattr_name(req_type));


Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>


David / dhildenb