The patch titled
Subject: page flags: prioritize kasan bits over last-cpuid
has been added to the -mm tree. Its filename is
page-flags-prioritize-kasan-bits-over-last-cpuid.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/page-flags-prioritize-kasan-bits-over-last-cpuid.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/page-flags-prioritize-kasan-bits-over-last-cpuid.patch
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------------------------------------------------------
From: Arnd Bergmann <arnd@xxxxxxxx>
Subject: page flags: prioritize kasan bits over last-cpuid
ARM64 randdconfig builds regularly run into a build error, especially when
NUMA_BALANCING and SPARSEMEM are enabled but not SPARSEMEM_VMEMMAP:
#error "KASAN: not enough bits in page flags for tag"
The last-cpuid bits are already contitional on the available space, so the
result of the calculation is a bit random on whether they were already
left out or not.
Adding the kasan tag bits before last-cpuid makes it much more likely to
end up with a successful build here, and should be reliable for randconfig
at least, as long as that does not randomize NR_CPUS or NODES_SHIFT but
uses the defaults.
In order for the modified check to not trigger in the x86 vdso32 code
where all constants are wrong (building with -m32), enclose all the
definitions with an #ifdef.
Link: http://lkml.kernel.org/r/20190722115520.3743282-1-arnd@xxxxxxxx
Link: https://lore.kernel.org/lkml/20190618095347.3850490-1-arnd@xxxxxxxx/
Fixes: 2813b9c02962 ("kasan, mm, arm64: tag non slab memory allocated via pagealloc")
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
Reviewed-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Reviewed-by: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Cc: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/page-flags-layout.h | 18 +++++++++++-------
1 file changed, 11 insertions(+), 7 deletions(-)
--- a/include/linux/page-flags-layout.h~page-flags-prioritize-kasan-bits-over-last-cpuid
+++ a/include/linux/page-flags-layout.h
@@ -32,6 +32,7 @@
#endif /* CONFIG_SPARSEMEM */
+#ifndef BUILD_VDSO32_64
/*
* page->flags layout:
*
@@ -76,20 +77,22 @@
#define LAST_CPUPID_SHIFT 0
#endif
-#if SECTIONS_WIDTH+ZONES_WIDTH+NODES_SHIFT+LAST_CPUPID_SHIFT <= BITS_PER_LONG - NR_PAGEFLAGS
+#ifdef CONFIG_KASAN_SW_TAGS
+#define KASAN_TAG_WIDTH 8
+#else
+#define KASAN_TAG_WIDTH 0
+#endif
+
+#if SECTIONS_WIDTH+ZONES_WIDTH+NODES_SHIFT+LAST_CPUPID_SHIFT+KASAN_TAG_WIDTH \
+ <= BITS_PER_LONG - NR_PAGEFLAGS
#define LAST_CPUPID_WIDTH LAST_CPUPID_SHIFT
#else
#define LAST_CPUPID_WIDTH 0
#endif
-#ifdef CONFIG_KASAN_SW_TAGS
-#define KASAN_TAG_WIDTH 8
#if SECTIONS_WIDTH+NODES_WIDTH+ZONES_WIDTH+LAST_CPUPID_WIDTH+KASAN_TAG_WIDTH \
> BITS_PER_LONG - NR_PAGEFLAGS
-#error "KASAN: not enough bits in page flags for tag"
-#endif
-#else
-#define KASAN_TAG_WIDTH 0
+#error "Not enough bits in page flags"
#endif
/*
@@ -104,4 +107,5 @@
#define LAST_CPUPID_NOT_IN_PAGE_FLAGS
#endif
+#endif
#endif /* _LINUX_PAGE_FLAGS_LAYOUT */
_
Patches currently in -mm which might be from arnd@xxxxxxxx are
kasan-remove-clang-version-check-for-kasan_stack.patch
ubsan-build-ubsanc-more-conservatively.patch
page-flags-prioritize-kasan-bits-over-last-cpuid.patch
mm-sparse-fix-memory-leak-of-sparsemap_buf-in-aliged-memory-fix.patch
