The quilt patch titled
Subject: s390/cpumf: unpoison STCCTM output buffer
has been removed from the -mm tree. Its filename was
s390-cpumf-unpoison-stcctm-output-buffer.patch
This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
------------------------------------------------------
From: Ilya Leoshkevich <iii@xxxxxxxxxxxxx>
Subject: s390/cpumf: unpoison STCCTM output buffer
Date: Fri, 21 Jun 2024 13:35:11 +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/20240621113706.315500-28-iii@xxxxxxxxxxxxx
Signed-off-by: Ilya Leoshkevich <iii@xxxxxxxxxxxxx>
Reported-by: Alexander Gordeev <agordeev@xxxxxxxxxxxxx>
Reviewed-by: Alexander Potapenko <glider@xxxxxxxxxx>
Acked-by: Heiko Carstens <hca@xxxxxxxxxxxxx>
Cc: Christian Borntraeger <borntraeger@xxxxxxxxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Hyeonggon Yoo <42.hyeyoo@xxxxxxxxx>
Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Cc: <kasan-dev@xxxxxxxxxxxxxxxx>
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/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 iii@xxxxxxxxxxxxx are
