+ s390-cpumf-unpoison-stcctm-output-buffer.patch added to mm-unstable branch

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Andrew Morton

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Jun 19, 2024, 8:59:09 PMJun 19
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The patch titled
Subject: s390/cpumf: unpoison STCCTM output buffer
has been added to the -mm mm-unstable branch. Its filename is
s390-cpumf-unpoison-stcctm-output-buffer.patch

This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/s390-cpumf-unpoison-stcctm-output-buffer.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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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: Ilya Leoshkevich <i...@linux.ibm.com>
Subject: s390/cpumf: unpoison STCCTM output buffer
Date: Wed, 19 Jun 2024 17:44:01 +0200

stcctm() uses the "Q" constraint for dest, therefore KMSAN does not
understand that it fills multiple doublewords pointed to by dest, not just
one. This results in false positives.

Unpoison the whole dest manually with kmsan_unpoison_memory().

Link: https://lkml.kernel.org/r/20240619154530...@linux.ibm.com
Signed-off-by: Ilya Leoshkevich <i...@linux.ibm.com>
Reported-by: Alexander Gordeev <agor...@linux.ibm.com>
Reviewed-by: Alexander Potapenko <gli...@google.com>
Acked-by: Heiko Carstens <h...@linux.ibm.com>
Cc: Christian Borntraeger <bornt...@linux.ibm.com>
Cc: Christoph Lameter <c...@linux.com>
Cc: David Rientjes <rien...@google.com>
Cc: Dmitry Vyukov <dvy...@google.com>
Cc: Hyeonggon Yoo <42.h...@gmail.com>
Cc: Joonsoo Kim <iamjoon...@lge.com>
Cc: <kasa...@googlegroups.com>
Cc: Marco Elver <el...@google.com>
Cc: Mark Rutland <mark.r...@arm.com>
Cc: Masami Hiramatsu (Google) <mhir...@kernel.org>
Cc: Pekka Enberg <pen...@kernel.org>
Cc: Roman Gushchin <roman.g...@linux.dev>
Cc: Steven Rostedt (Google) <ros...@goodmis.org>
Cc: Sven Schnelle <sv...@linux.ibm.com>
Cc: Vasily Gorbik <g...@linux.ibm.com>
Cc: Vlastimil Babka <vba...@suse.cz>
Signed-off-by: Andrew Morton <ak...@linux-foundation.org>
---

arch/s390/include/asm/cpu_mf.h | 6 ++++++
1 file changed, 6 insertions(+)

--- a/arch/s390/include/asm/cpu_mf.h~s390-cpumf-unpoison-stcctm-output-buffer
+++ a/arch/s390/include/asm/cpu_mf.h
@@ -10,6 +10,7 @@
#define _ASM_S390_CPU_MF_H

#include <linux/errno.h>
+#include <linux/kmsan-checks.h>
#include <asm/asm-extable.h>
#include <asm/facility.h>

@@ -239,6 +240,11 @@ static __always_inline int stcctm(enum s
: "=d" (cc)
: "Q" (*dest), "d" (range), "i" (set)
: "cc", "memory");
+ /*
+ * If cc == 2, less than RANGE counters are stored, but it's not easy
+ * to tell how many. Always unpoison the whole range for simplicity.
+ */
+ kmsan_unpoison_memory(dest, range * sizeof(u64));
return cc;
}

_

Patches currently in -mm which might be from i...@linux.ibm.com 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-introduce-memset_no_sanitize_memory.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-disable-kmsan-when-checking-the-padding-bytes.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-uaccess-add-the-missing-linux-instrumentedh-include.patch
s390-unwind-disable-kmsan-checks.patch
s390-kmsan-implement-the-architecture-specific-functions.patch
kmsan-enable-on-s390.patch

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