Messages in this thread | | | From | Arnd Bergmann <> | Date | Mon, 5 Aug 2019 20:35:40 +0200 | Subject | Re: [PATCH] page flags: prioritize kasan bits over last-cpuid |
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On Mon, Aug 5, 2019 at 6:51 PM Guenter Roeck <linux@roeck-us.net> wrote: > > On Fri, Aug 02, 2019 at 09:49:02PM -0700, 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. > > > > This results in > > ./include/linux/page-flags-layout.h:95:2: error: #error "Not enough bits in page flags" > #error "Not enough bits in page flags" > > when trying to build mipsel64:fuloong2e_defconfig.
Do you have my follow-up fix applied?
https://ozlabs.org/~akpm/mmots/broken-out/page-flags-prioritize-kasan-bits-over-last-cpuid-fix.patch
Arnd
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