| Message ID | 20190722115520.3743282-1-arnd@arndb.de |
|---|---|
| State | New |
| Headers | show |
| Series | [v3] page flags: prioritize kasan bits over last-cpuid | expand |
On 7/22/19 2:55 PM, Arnd Bergmann wrote: > 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. > > Fixes: 2813b9c02962 ("kasan, mm, arm64: tag non slab memory allocated via pagealloc") > Link: https://lore.kernel.org/lkml/20190618095347.3850490-1-arnd@arndb.de/ > Reviewed-by: Andrey Konovalov <andreyknvl@google.com> > Signed-off-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
diff --git a/include/linux/page-flags-layout.h b/include/linux/page-flags-layout.h index 1dda31825ec4..71283739ffd2 100644 --- a/include/linux/page-flags-layout.h +++ b/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 */
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. Fixes: 2813b9c02962 ("kasan, mm, arm64: tag non slab memory allocated via pagealloc") Link: https://lore.kernel.org/lkml/20190618095347.3850490-1-arnd@arndb.de/ Reviewed-by: Andrey Konovalov <andreyknvl@google.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de> --- v3: rework the #error message to make more sense v2: fix a build regression with vdso32 --- include/linux/page-flags-layout.h | 18 +++++++++++------- 1 file changed, 11 insertions(+), 7 deletions(-) -- 2.20.0