Messages in this thread | | | Date | Mon, 5 Aug 2019 13:18:57 -0700 | From | Guenter Roeck <> | Subject | Re: [PATCH] page flags: prioritize kasan bits over last-cpuid |
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On Mon, Aug 05, 2019 at 09:57:59PM +0200, Arnd Bergmann wrote: > On Mon, Aug 5, 2019 at 8:52 PM Guenter Roeck <linux@roeck-us.net> wrote: > > On Mon, Aug 05, 2019 at 08:35:40PM +0200, Arnd Bergmann wrote: > > > 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 > > > > > > > No. I see the failure in next-20190729..next-20190805. > > > > I didn't try to apply that patch, but I don't see > > arch/mips/vdso/vdso.h in the tree. I only see > > > > arch/mips/include/asm/vdso.h > > arch/mips/include/asm/vdso/vdso.h > > > > Are you sure that your patch can be applied as-is ? > > Ah, right, we now have support for the generic vdso on mips, > so the file got moved from arch/mips/vdso/vdso.h to > arch/mips/include/asm/vdso/vdso.h > > Try applying it to the new location then. I think it should still apply, > but have not tried it. >
Turns out it is applied there (it looks like it was merged into the original patch). But it doesn't help; the build failure is still there. Reverting "page flags: prioritize kasan bits over last-cpuid" on top of next-20190805 fixes the problem for me.
Guenter
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