# git rev-parse -q --verify 8b11ec1b5ffb54f71cb5a5e5c8c4d36e5d113085^{commit} 8b11ec1b5ffb54f71cb5a5e5c8c4d36e5d113085 already have revision, skipping fetch # git checkout -q -f -B kisskb 8b11ec1b5ffb54f71cb5a5e5c8c4d36e5d113085 # git clean -qxdf # < git log -1 # commit 8b11ec1b5ffb54f71cb5a5e5c8c4d36e5d113085 # Author: Linus Torvalds # Date: Wed Aug 1 13:43:38 2018 -0700 # # mm: do not initialize TLB stack vma's with vma_init() # # Commit 2c4541e24c55 ("mm: use vma_init() to initialize VMAs on stack and # data segments") tried to initialize various left-over ad-hoc vma's # "properly", but actually made things worse for the temporary vma's used # for TLB flushing. # # vma_init() doesn't actually initialize all of the vma, just a few # fields, so doing something like # # - struct vm_area_struct vma = { .vm_mm = tlb->mm, }; # + struct vm_area_struct vma; # + # + vma_init(&vma, tlb->mm); # # was actually very bad: instead of having a nicely initialized vma with # every field but "vm_mm" zeroed, you'd have an entirely uninitialized vma # with only a couple of fields initialized. And they weren't even fields # that the code in question mostly cared about. # # The flush_tlb_range() function takes a "struct vma" rather than a # "struct mm_struct", because a few architectures actually care about what # kind of range it is - being able to only do an ITLB flush if it's a # range that doesn't have data accesses enabled, for example. And all the # normal users already have the vma for doing the range invalidation. # # But a few people want to call flush_tlb_range() with a range they just # made up, so they also end up using a made-up vma. x86 just has a # special "flush_tlb_mm_range()" function for this, but other # architectures (arm and ia64) do the "use fake vma" thing instead, and # thus got caught up in the vma_init() changes. # # At the same time, the TLB flushing code really doesn't care about most # other fields in the vma, so vma_init() is just unnecessary and # pointless. # # This fixes things by having an explicit "this is just an initializer for # the TLB flush" initializer macro, which is used by the arm/arm64/ia64 # people who mis-use this interface with just a dummy vma. # # Fixes: 2c4541e24c55 ("mm: use vma_init() to initialize VMAs on stack and data segments") # Cc: Dmitry Vyukov # Cc: Oleg Nesterov # Cc: Andrea Arcangeli # Cc: Kirill Shutemov # Cc: Andrew Morton # Cc: John Stultz # Cc: Hugh Dickins # Signed-off-by: Linus Torvalds # < /opt/cross/kisskb/gcc-5.2.0-nolibc/powerpc64le-linux/bin/powerpc64le-linux-gcc --version # < git log --format=%s --max-count=1 8b11ec1b5ffb54f71cb5a5e5c8c4d36e5d113085 # < make -s -j 48 ARCH=powerpc O=/kisskb/build/linus-rand_randconfig+ppc64le_ppc64le CROSS_COMPILE=/opt/cross/kisskb/gcc-5.2.0-nolibc/powerpc64le-linux/bin/powerpc64le-linux- randconfig KCONFIG_SEED=0x4DD99881 # Added to kconfig CONFIG_STANDALONE=y # Added to kconfig CONFIG_BUILD_DOCSRC=n # Added to kconfig CONFIG_MODULE_SIG=n # Added to kconfig CONFIG_CPU_BIG_ENDIAN=n # Added to kconfig CONFIG_CPU_LITTLE_ENDIAN=y # Added to kconfig CONFIG_PPC_64=y # Added to kconfig CONFIG_PPC_BOOK3E_64=n # Added to kconfig CONFIG_PPC_BOOK3S_64=y # Added to kconfig CONFIG_PPC_DISABLE_WERROR=y # Added to kconfig CONFIG_SECTION_MISMATCH_WARN_ONLY=y # Added to kconfig CONFIG_PREVENT_FIRMWARE_BUILD=y # Added to kconfig CONFIG_LD_HEAD_STUB_CATCH=y # Added to kconfig # Added to kconfig # yes \n | make -s -j 48 ARCH=powerpc O=/kisskb/build/linus-rand_randconfig+ppc64le_ppc64le CROSS_COMPILE=/opt/cross/kisskb/gcc-5.2.0-nolibc/powerpc64le-linux/bin/powerpc64le-linux- oldconfig yes: standard output: Broken pipe yes: write error # make -s -j 48 ARCH=powerpc O=/kisskb/build/linus-rand_randconfig+ppc64le_ppc64le CROSS_COMPILE=/opt/cross/kisskb/gcc-5.2.0-nolibc/powerpc64le-linux/bin/powerpc64le-linux- In file included from /kisskb/src/arch/powerpc/xmon/xmon.c:66:0: /kisskb/src/arch/powerpc/xmon/dis-asm.h: In function 'print_insn_powerpc': /kisskb/src/arch/powerpc/xmon/dis-asm.h:20:9: warning: format '%x' expects argument of type 'unsigned int', but argument 2 has type 'long unsigned int' [-Wformat=] printf("%.8x", insn); ^ /kisskb/src/arch/powerpc/xmon/dis-asm.h: In function 'print_insn_spu': /kisskb/src/arch/powerpc/xmon/dis-asm.h:26:9: warning: format '%x' expects argument of type 'unsigned int', but argument 2 has type 'long unsigned int' [-Wformat=] printf("%.8x", insn); ^ WARNING: modpost: Found 2 section mismatch(es). To see full details build your kernel with: 'make CONFIG_DEBUG_SECTION_MISMATCH=y' WARNING: 6 bad relocations c00000000382c900 R_PPC64_ADDR64 vfio_external_check_extension c00000000382c908 R_PPC64_ADDR64 vfio_group_set_kvm c00000000382c910 R_PPC64_ADDR64 vfio_group_put_external_user c00000000382c918 R_PPC64_ADDR64 vfio_group_get_external_user c00000000382c920 R_PPC64_ADDR64 vfio_external_group_match_file c00000000382cb50 R_PPC64_ADDR64 cfhsi_get_ops Completed OK # rm -rf /kisskb/build/linus-rand_randconfig+ppc64le_ppc64le # Build took: 0:04:30.667494