The patch titled Subject: x86: kmsan: disable instrumentation of unsupported code has been added to the -mm mm-unstable branch. Its filename is x86-kmsan-disable-instrumentation-of-unsupported-code.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/x86-kmsan-disable-instrumentation-of-unsupported-code.patch This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Alexander Potapenko <glider@xxxxxxxxxx> Subject: x86: kmsan: disable instrumentation of unsupported code Date: Fri, 26 Aug 2022 17:07:56 +0200 Instrumenting some files with KMSAN will result in kernel being unable to link, boot or crashing at runtime for various reasons (e.g. infinite recursion caused by instrumentation hooks calling instrumented code again). Completely omit KMSAN instrumentation in the following places: - arch/x86/boot and arch/x86/realmode/rm, as KMSAN doesn't work for i386; - arch/x86/entry/vdso, which isn't linked with KMSAN runtime; - three files in arch/x86/kernel - boot problems; - arch/x86/mm/cpu_entry_area.c - recursion. Link: https://lkml.kernel.org/r/20220826150807.723137-34-glider@xxxxxxxxxx Signed-off-by: Alexander Potapenko <glider@xxxxxxxxxx> Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx> Cc: Alexei Starovoitov <ast@xxxxxxxxxx> Cc: Andrey Konovalov <andreyknvl@xxxxxxxxx> Cc: Andrey Konovalov <andreyknvl@xxxxxxxxxx> Cc: Andy Lutomirski <luto@xxxxxxxxxx> Cc: Arnd Bergmann <arnd@xxxxxxxx> Cc: Borislav Petkov <bp@xxxxxxxxx> Cc: Christoph Hellwig <hch@xxxxxx> Cc: Christoph Lameter <cl@xxxxxxxxx> Cc: David Rientjes <rientjes@xxxxxxxxxx> Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx> Cc: Eric Biggers <ebiggers@xxxxxxxxxx> Cc: Eric Dumazet <edumazet@xxxxxxxxxx> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Cc: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> Cc: Ilya Leoshkevich <iii@xxxxxxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxxxxx> Cc: Jens Axboe <axboe@xxxxxxxxx> Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx> Cc: Kees Cook <keescook@xxxxxxxxxxxx> Cc: Marco Elver <elver@xxxxxxxxxx> Cc: Mark Rutland <mark.rutland@xxxxxxx> Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx> Cc: Michael S. Tsirkin <mst@xxxxxxxxxx> Cc: Pekka Enberg <penberg@xxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Petr Mladek <pmladek@xxxxxxxx> Cc: Steven Rostedt <rostedt@xxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: Vasily Gorbik <gor@xxxxxxxxxxxxx> Cc: Vegard Nossum <vegard.nossum@xxxxxxxxxx> Cc: Vlastimil Babka <vbabka@xxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- arch/x86/boot/Makefile | 1 + arch/x86/boot/compressed/Makefile | 1 + arch/x86/entry/vdso/Makefile | 3 +++ arch/x86/kernel/Makefile | 2 ++ arch/x86/kernel/cpu/Makefile | 1 + arch/x86/mm/Makefile | 2 ++ arch/x86/realmode/rm/Makefile | 1 + 7 files changed, 11 insertions(+) --- a/arch/x86/boot/compressed/Makefile~x86-kmsan-disable-instrumentation-of-unsupported-code +++ a/arch/x86/boot/compressed/Makefile @@ -20,6 +20,7 @@ # Sanitizer runtimes are unavailable and cannot be linked for early boot code. KASAN_SANITIZE := n KCSAN_SANITIZE := n +KMSAN_SANITIZE := n OBJECT_FILES_NON_STANDARD := y # Prevents link failures: __sanitizer_cov_trace_pc() is not linked in. --- a/arch/x86/boot/Makefile~x86-kmsan-disable-instrumentation-of-unsupported-code +++ a/arch/x86/boot/Makefile @@ -12,6 +12,7 @@ # Sanitizer runtimes are unavailable and cannot be linked for early boot code. KASAN_SANITIZE := n KCSAN_SANITIZE := n +KMSAN_SANITIZE := n OBJECT_FILES_NON_STANDARD := y # Kernel does not boot with kcov instrumentation here. --- a/arch/x86/entry/vdso/Makefile~x86-kmsan-disable-instrumentation-of-unsupported-code +++ a/arch/x86/entry/vdso/Makefile @@ -11,6 +11,9 @@ include $(srctree)/lib/vdso/Makefile # Sanitizer runtimes are unavailable and cannot be linked here. KASAN_SANITIZE := n +KMSAN_SANITIZE_vclock_gettime.o := n +KMSAN_SANITIZE_vgetcpu.o := n + UBSAN_SANITIZE := n KCSAN_SANITIZE := n OBJECT_FILES_NON_STANDARD := y --- a/arch/x86/kernel/cpu/Makefile~x86-kmsan-disable-instrumentation-of-unsupported-code +++ a/arch/x86/kernel/cpu/Makefile @@ -12,6 +12,7 @@ endif # If these files are instrumented, boot hangs during the first second. KCOV_INSTRUMENT_common.o := n KCOV_INSTRUMENT_perf_event.o := n +KMSAN_SANITIZE_common.o := n # As above, instrumenting secondary CPU boot code causes boot hangs. KCSAN_SANITIZE_common.o := n --- a/arch/x86/kernel/Makefile~x86-kmsan-disable-instrumentation-of-unsupported-code +++ a/arch/x86/kernel/Makefile @@ -33,6 +33,8 @@ KASAN_SANITIZE_sev.o := n # With some compiler versions the generated code results in boot hangs, caused # by several compilation units. To be safe, disable all instrumentation. KCSAN_SANITIZE := n +KMSAN_SANITIZE_head$(BITS).o := n +KMSAN_SANITIZE_nmi.o := n # If instrumentation of this dir is enabled, boot hangs during first second. # Probably could be more selective here, but note that files related to irqs, --- a/arch/x86/mm/Makefile~x86-kmsan-disable-instrumentation-of-unsupported-code +++ a/arch/x86/mm/Makefile @@ -12,6 +12,8 @@ KASAN_SANITIZE_mem_encrypt_identity.o := # Disable KCSAN entirely, because otherwise we get warnings that some functions # reference __initdata sections. KCSAN_SANITIZE := n +# Avoid recursion by not calling KMSAN hooks for CEA code. +KMSAN_SANITIZE_cpu_entry_area.o := n ifdef CONFIG_FUNCTION_TRACER CFLAGS_REMOVE_mem_encrypt.o = -pg --- a/arch/x86/realmode/rm/Makefile~x86-kmsan-disable-instrumentation-of-unsupported-code +++ a/arch/x86/realmode/rm/Makefile @@ -10,6 +10,7 @@ # Sanitizer runtimes are unavailable and cannot be linked here. KASAN_SANITIZE := n KCSAN_SANITIZE := n +KMSAN_SANITIZE := n OBJECT_FILES_NON_STANDARD := y # Prevents link failures: __sanitizer_cov_trace_pc() is not linked in. _ Patches currently in -mm which might be from glider@xxxxxxxxxx are stackdepot-reserve-5-extra-bits-in-depot_stack_handle_t.patch instrumentedh-allow-instrumenting-both-sides-of-copy_from_user.patch x86-asm-instrument-usercopy-in-get_user-and-put_user.patch asm-generic-instrument-usercopy-in-cacheflushh.patch kmsan-add-rest-documentation.patch kmsan-introduce-__no_sanitize_memory-and-__no_kmsan_checks.patch kmsan-mark-noinstr-as-__no_sanitize_memory.patch x86-kmsan-pgtable-reduce-vmalloc-space.patch libnvdimm-pfn_dev-increase-max_struct_page_size.patch kmsan-add-kmsan-runtime-core.patch kmsan-disable-instrumentation-of-unsupported-common-kernel-code.patch maintainers-add-entry-for-kmsan.patch mm-kmsan-maintain-kmsan-metadata-for-page-operations.patch mm-kmsan-call-kmsan-hooks-from-slub-code.patch kmsan-handle-task-creation-and-exiting.patch init-kmsan-call-kmsan-initialization-routines.patch instrumentedh-add-kmsan-support.patch kmsan-unpoison-tlb-in-arch_tlb_gather_mmu.patch kmsan-add-iomap-support.patch input-libps2-mark-data-received-in-__ps2_command-as-initialized.patch dma-kmsan-unpoison-dma-mappings.patch virtio-kmsan-check-unpoison-scatterlist-in-vring_map_one_sg.patch kmsan-handle-memory-sent-to-from-usb.patch kmsan-add-tests-for-kmsan.patch kmsan-disable-strscpy-optimization-under-kmsan.patch crypto-kmsan-disable-accelerated-configs-under-kmsan.patch kmsan-disable-physical-page-merging-in-biovec.patch block-kmsan-skip-bio-block-merging-logic-for-kmsan.patch kcov-kmsan-unpoison-area-list-in-kcov_remote_area_put.patch security-kmsan-fix-interoperability-with-auto-initialization.patch objtool-kmsan-list-kmsan-api-functions-as-uaccess-safe.patch x86-kmsan-disable-instrumentation-of-unsupported-code.patch x86-kmsan-skip-shadow-checks-in-__switch_to.patch x86-kmsan-handle-open-coded-assembly-in-lib-iomemc.patch x86-kmsan-use-__msan_-string-functions-where-possible.patch x86-kmsan-sync-metadata-pages-on-page-fault.patch x86-kasan-kmsan-support-config_generic_csum-on-x86-enable-it-for-kasan-kmsan.patch x86-fs-kmsan-disable-config_dcache_word_access.patch x86-kmsan-dont-instrument-stack-walking-functions.patch entry-kmsan-introduce-kmsan_unpoison_entry_regs.patch bpf-kmsan-initialize-bpf-registers-with-zeroes.patch mm-fs-initialize-fsdata-passed-to-write_begin-write_end-interface.patch x86-kmsan-enable-kmsan-builds-for-x86.patch