The patch titled
Subject: s390/boot: add the KMSAN runtime stub
has been added to the -mm mm-unstable branch. Its filename is
s390-boot-add-the-kmsan-runtime-stub.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/s390-boot-add-the-kmsan-runtime-stub.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: Ilya Leoshkevich <iii@xxxxxxxxxxxxx>
Subject: s390/boot: add the KMSAN runtime stub
Date: Thu, 13 Jun 2024 17:34:24 +0200
It should be possible to have inline functions in the s390 header
files, which call kmsan_unpoison_memory(). The problem is that these
header files might be included by the decompressor, which does not
contain KMSAN runtime, causing linker errors.
Not compiling these calls if __SANITIZE_MEMORY__ is not defined -
either by changing kmsan-checks.h or at the call sites - may cause
unintended side effects, since calling these functions from an
uninstrumented code that is linked into the kernel is valid use case.
One might want to explicitly distinguish between the kernel and the
decompressor. Checking for a decompressor-specific #define is quite
heavy-handed, and will have to be done at all call sites.
A more generic approach is to provide a dummy kmsan_unpoison_memory()
definition. This produces some runtime overhead, but only when building
with CONFIG_KMSAN. The benefit is that it does not disturb the existing
KMSAN build logic and call sites don't need to be changed.
Link: https://lkml.kernel.org/r/20240613153924.961511-23-iii@xxxxxxxxxxxxx
Signed-off-by: Ilya Leoshkevich <iii@xxxxxxxxxxxxx>
Reviewed-by: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Alexander Gordeev <agordeev@xxxxxxxxxxxxx>
Cc: Christian Borntraeger <borntraeger@xxxxxxxxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Heiko Carstens <hca@xxxxxxxxxxxxx>
Cc: Hyeonggon Yoo <42.hyeyoo@xxxxxxxxx>
Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Cc: Marco Elver <elver@xxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
Cc: Pekka Enberg <penberg@xxxxxxxxxx>
Cc: Roman Gushchin <roman.gushchin@xxxxxxxxx>
Cc: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
Cc: Sven Schnelle <svens@xxxxxxxxxxxxx>
Cc: Vasily Gorbik <gor@xxxxxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/s390/boot/Makefile | 1 +
arch/s390/boot/kmsan.c | 6 ++++++
2 files changed, 7 insertions(+)
--- /dev/null
+++ a/arch/s390/boot/kmsan.c
@@ -0,0 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/kmsan-checks.h>
+
+void kmsan_unpoison_memory(const void *address, size_t size)
+{
+}
--- a/arch/s390/boot/Makefile~s390-boot-add-the-kmsan-runtime-stub
+++ a/arch/s390/boot/Makefile
@@ -44,6 +44,7 @@ obj-$(findstring y, $(CONFIG_PROTECTED_V
obj-$(CONFIG_RANDOMIZE_BASE) += kaslr.o
obj-y += $(if $(CONFIG_KERNEL_UNCOMPRESSED),,decompressor.o) info.o
obj-$(CONFIG_KERNEL_ZSTD) += clz_ctz.o
+obj-$(CONFIG_KMSAN) += kmsan.o
obj-all := $(obj-y) piggy.o syms.o
targets := bzImage section_cmp.boot.data section_cmp.boot.preserved.data $(obj-y)
_
Patches currently in -mm which might be from iii@xxxxxxxxxxxxx are
ftrace-unpoison-ftrace_regs-in-ftrace_ops_list_func.patch
kmsan-make-the-tests-compatible-with-kmsanpanic=1.patch
kmsan-disable-kmsan-when-deferred_struct_page_init-is-enabled.patch
kmsan-increase-the-maximum-store-size-to-4096.patch
kmsan-fix-is_bad_asm_addr-on-arches-with-overlapping-address-spaces.patch
kmsan-fix-kmsan_copy_to_user-on-arches-with-overlapping-address-spaces.patch
kmsan-remove-a-useless-assignment-from-kmsan_vmap_pages_range_noflush.patch
kmsan-remove-an-x86-specific-include-from-kmsanh.patch
kmsan-expose-kmsan_get_metadata.patch
kmsan-export-panic_on_kmsan.patch
kmsan-allow-disabling-kmsan-checks-for-the-current-task.patch
kmsan-support-slab_poison.patch
kmsan-use-align_down-in-kmsan_get_metadata.patch
kmsan-do-not-round-up-pg_data_t-size.patch
mm-slub-let-kmsan-access-metadata.patch
mm-slub-unpoison-the-memchr_inv-return-value.patch
mm-kfence-disable-kmsan-when-checking-the-canary.patch
lib-zlib-unpoison-dfltcc-output-buffers.patch
kmsan-accept-ranges-starting-with-0-on-s390.patch
s390-boot-turn-off-kmsan.patch
s390-use-a-larger-stack-for-kmsan.patch
s390-boot-add-the-kmsan-runtime-stub.patch
s390-checksum-add-a-kmsan-check.patch
s390-cpacf-unpoison-the-results-of-cpacf_trng.patch
s390-cpumf-unpoison-stcctm-output-buffer.patch
s390-diag-unpoison-diag224-output-buffer.patch
s390-ftrace-unpoison-ftrace_regs-in-kprobe_ftrace_handler.patch
s390-irqflags-do-not-instrument-arch_local_irq_-with-kmsan.patch
s390-mm-define-kmsan-metadata-for-vmalloc-and-modules.patch
s390-string-add-kmsan-support.patch
s390-traps-unpoison-the-kernel_stack_overflows-pt_regs.patch
s390-uaccess-add-kmsan-support-to-put_user-and-get_user.patch
s390-unwind-disable-kmsan-checks.patch
s390-implement-the-architecture-specific-kmsan-functions.patch
kmsan-enable-on-s390.patch
