On Wed, Nov 24, 2021 at 06:04:20PM +0530, Naresh Kamboju wrote: > Regression found on arm gcc-11 builds with tinyconfig and allnoconfig. > Following build warnings / errors reported on stable-rc 4.9. > > metadata: > git_describe: v4.9.290-208-gb2ae18f41670 > git_repo: https://gitlab.com/Linaro/lkft/mirrors/stable/linux-stable-rc > git_short_log: b2ae18f41670 (\"Linux 4.9.291-rc1\") > target_arch: arm > toolchain: gcc-11 / gcc-10 / gcc-9 / gcc-8 > > build error : > -------------- > make --silent --keep-going --jobs=8 > O=/home/tuxbuild/.cache/tuxmake/builds/current ARCH=arm > CROSS_COMPILE=arm-linux-gnueabihf- 'CC=sccache > arm-linux-gnueabihf-gcc' 'HOSTCC=sccache gcc' > In file included from arch/arm/include/asm/tlb.h:28, > from arch/arm/mm/init.c:34: > include/asm-generic/tlb.h: In function 'tlb_flush_pmd_range': > include/asm-generic/tlb.h:208:54: error: 'PMD_SIZE' undeclared (first > use in this function); did you mean 'PUD_SIZE'? > 208 | if (tlb->page_size != 0 && tlb->page_size != PMD_SIZE) > | ^~~~~~~~ > | PUD_SIZE > include/asm-generic/tlb.h:208:54: note: each undeclared identifier is > reported only once for each function it appears in > make[2]: *** [scripts/Makefile.build:307: arch/arm/mm/init.o] Error 1 > make[2]: Target '__build' not remade because of errors. > make[1]: *** [Makefile:1036: arch/arm/mm] Error 2 > > Reported-by: Linux Kernel Functional Testing <lkft@xxxxxxxxxx> > > Patch pointing to, > > hugetlbfs: flush TLBs correctly after huge_pmd_unshare > commit a4a118f2eead1d6c49e00765de89878288d4b890 upstream. > > When __unmap_hugepage_range() calls to huge_pmd_unshare() succeed, a TLB > flush is missing. This TLB flush must be performed before releasing the > i_mmap_rwsem, in order to prevent an unshared PMDs page from being > released and reused before the TLB flush took place. > > Arguably, a comprehensive solution would use mmu_gather interface to > batch the TLB flushes and the PMDs page release, however it is not an > easy solution: (1) try_to_unmap_one() and try_to_migrate_one() also call > huge_pmd_unshare() and they cannot use the mmu_gather interface; and (2) > deferring the release of the page reference for the PMDs page until > after i_mmap_rwsem is dropeed can confuse huge_pmd_unshare() into > thinking PMDs are shared when they are not. > > Fix __unmap_hugepage_range() by adding the missing TLB flush, and > forcing a flush when unshare is successful. > > Fixes: 24669e58477e ("hugetlb: use mmu_gather instead of a temporary > linked list for accumulating pages)" # 3.6 > Signed-off-by: Nadav Amit <namit@xxxxxxxxxx> > Reviewed-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx> > Cc: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx> > Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> > Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> > Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> > Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> > > > > build link: > ----------- > https://builds.tuxbuild.com//21Mf9eMMjq4oO5ZflMwRCPssSc0/build.log > > build config: > ------------- > https://builds.tuxbuild.com//21Mf9eMMjq4oO5ZflMwRCPssSc0/config > > # To install tuxmake on your system globally > # sudo pip3 install -U tuxmake > tuxmake --runtime podman --target-arch arm --toolchain gcc-11 > --kconfig tinyconfig Should now be resolved in -rc2. thanks, greg k-h
