The patch titled
Subject: mm/cma.c: fail if fixed declaration can't be honored
has been added to the -mm tree. Its filename is
cma-fail-if-fixed-declaration-cant-be-honored.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/cma-fail-if-fixed-declaration-cant-be-honored.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/cma-fail-if-fixed-declaration-cant-be-honored.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Doug Berger <opendmb@xxxxxxxxx>
Subject: mm/cma.c: fail if fixed declaration can't be honored
The description of cma_declare_contiguous() indicates that if the 'fixed'
argument is true the reserved contiguous area must be exactly at the
address of the 'base' argument.
However, the function currently allows the 'base', 'size', and 'limit'
arguments to be silently adjusted to meet alignment constraints. This
commit enforces the documented behavior through explicit checks that
return an error if the region does not fit within a specified region.
Link: http://lkml.kernel.org/r/1561422051-16142-1-git-send-email-opendmb@xxxxxxxxx
Fixes: 5ea3b1b2f8ad ("cma: add placement specifier for "cma=" kernel parameter")
Signed-off-by: Doug Berger <opendmb@xxxxxxxxx>
Acked-by: Michal Nazarewicz <mina86@xxxxxxxxxx>
Cc: Yue Hu <huyue2@xxxxxxxxxx>
Cc: Mike Rapoport <rppt@xxxxxxxxxxxxx>
Cc: Laura Abbott <labbott@xxxxxxxxxx>
Cc: Peng Fan <peng.fan@xxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
Cc: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/cma.c | 13 +++++++++++++
1 file changed, 13 insertions(+)
--- a/mm/cma.c~cma-fail-if-fixed-declaration-cant-be-honored
+++ a/mm/cma.c
@@ -278,6 +278,12 @@ int __init cma_declare_contiguous(phys_a
*/
alignment = max(alignment, (phys_addr_t)PAGE_SIZE <<
max_t(unsigned long, MAX_ORDER - 1, pageblock_order));
+ if (fixed && base & (alignment - 1)) {
+ ret = -EINVAL;
+ pr_err("Region at %pa must be aligned to %pa bytes\n",
+ &base, &alignment);
+ goto err;
+ }
base = ALIGN(base, alignment);
size = ALIGN(size, alignment);
limit &= ~(alignment - 1);
@@ -308,6 +314,13 @@ int __init cma_declare_contiguous(phys_a
if (limit == 0 || limit > memblock_end)
limit = memblock_end;
+ if (base + size > limit) {
+ ret = -EINVAL;
+ pr_err("Size (%pa) of region at %pa exceeds limit (%pa)\n",
+ &size, &base, &limit);
+ goto err;
+ }
+
/* Reserve memory */
if (fixed) {
if (memblock_is_region_reserved(base, size) ||
_
Patches currently in -mm which might be from opendmb@xxxxxxxxx are
cma-fail-if-fixed-declaration-cant-be-honored.patch
