+ x86-kmsan-sync-metadata-pages-on-page-fault.patch added to mm-unstable branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: x86: kmsan: sync metadata pages on page fault
has been added to the -mm mm-unstable branch.  Its filename is
     x86-kmsan-sync-metadata-pages-on-page-fault.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/x86-kmsan-sync-metadata-pages-on-page-fault.patch

This patch will later appear in the mm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Alexander Potapenko <glider@google.com>
Subject: x86: kmsan: sync metadata pages on page fault
Date: Fri, 26 Aug 2022 17:08:00 +0200

KMSAN assumes shadow and origin pages for every allocated page are
accessible.  For pages between [VMALLOC_START, VMALLOC_END] those metadata
pages start at KMSAN_VMALLOC_SHADOW_START and KMSAN_VMALLOC_ORIGIN_START,
therefore we must sync a bigger memory region.

Link: https://lkml.kernel.org/r/20220826150807.723137-38-glider@google.com
Signed-off-by: Alexander Potapenko <glider@google.com>

Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Eric Biggers <ebiggers@google.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Ilya Leoshkevich <iii@linux.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Marco Elver <elver@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 arch/x86/mm/fault.c |   23 ++++++++++++++++++++++-
 1 file changed, 22 insertions(+), 1 deletion(-)

--- a/arch/x86/mm/fault.c~x86-kmsan-sync-metadata-pages-on-page-fault
+++ a/arch/x86/mm/fault.c
@@ -260,7 +260,7 @@ static noinline int vmalloc_fault(unsign
 }
 NOKPROBE_SYMBOL(vmalloc_fault);
 
-void arch_sync_kernel_mappings(unsigned long start, unsigned long end)
+static void __arch_sync_kernel_mappings(unsigned long start, unsigned long end)
 {
 	unsigned long addr;
 
@@ -284,6 +284,27 @@ void arch_sync_kernel_mappings(unsigned
 	}
 }
 
+void arch_sync_kernel_mappings(unsigned long start, unsigned long end)
+{
+	__arch_sync_kernel_mappings(start, end);
+#ifdef CONFIG_KMSAN
+	/*
+	 * KMSAN maintains two additional metadata page mappings for the
+	 * [VMALLOC_START, VMALLOC_END) range. These mappings start at
+	 * KMSAN_VMALLOC_SHADOW_START and KMSAN_VMALLOC_ORIGIN_START and
+	 * have to be synced together with the vmalloc memory mapping.
+	 */
+	if (start >= VMALLOC_START && end < VMALLOC_END) {
+		__arch_sync_kernel_mappings(
+			start - VMALLOC_START + KMSAN_VMALLOC_SHADOW_START,
+			end - VMALLOC_START + KMSAN_VMALLOC_SHADOW_START);
+		__arch_sync_kernel_mappings(
+			start - VMALLOC_START + KMSAN_VMALLOC_ORIGIN_START,
+			end - VMALLOC_START + KMSAN_VMALLOC_ORIGIN_START);
+	}
+#endif
+}
+
 static bool low_pfn(unsigned long pfn)
 {
 	return pfn < max_low_pfn;
_

Patches currently in -mm which might be from glider@google.com 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