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Mon, 10 Nov 2025 09:30:19 GMT Received: from smtpav06.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 6D2AC20049; Mon, 10 Nov 2025 09:30:19 +0000 (GMT) Received: from smtpav06.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 828DA20040; Mon, 10 Nov 2025 09:30:18 +0000 (GMT) Received: from osiris (unknown [9.87.148.55]) by smtpav06.fra02v.mail.ibm.com (Postfix) with ESMTPS; Mon, 10 Nov 2025 09:30:18 +0000 (GMT) Date: Mon, 10 Nov 2025 10:30:17 +0100 From: Heiko Carstens To: Aleksei Nikiforov Cc: Alexander Potapenko , Marco Elver , Dmitry Vyukov , Andrew Morton , kasan-dev@googlegroups.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , Thomas Huth , Juergen Christ , Ilya Leoshkevich Subject: Re: [PATCH v2] s390/fpu: Fix false-positive kmsan report in fpu_vstl function Message-ID: <20251110093017.15528A26-hca@linux.ibm.com> References: <20251107155914.1407772-3-aleksei.nikiforov@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20251107155914.1407772-3-aleksei.nikiforov@linux.ibm.com> X-TM-AS-GCONF: 00 X-Authority-Analysis: v=2.4 cv=MtZfKmae c=1 sm=1 tr=0 ts=6911b0b0 cx=c_pps a=3Bg1Hr4SwmMryq2xdFQyZA==:117 a=3Bg1Hr4SwmMryq2xdFQyZA==:17 a=kj9zAlcOel0A:10 a=6UeiqGixMTsA:10 a=VkNPw1HP01LnGYTKEx00:22 a=VnNF1IyMAAAA:8 a=bXxCFtWIKm37yWNRadsA:9 a=CjuIK1q_8ugA:10 a=cPQSjfK2_nFv0Q5t_7PE:22 X-Proofpoint-GUID: a0sNEDIK0Gr--rLC5ZSC2Y2pLdE44ef_ X-Proofpoint-ORIG-GUID: YUzRASJ9uQFIpYFhIfz1zgYQR8wytDKp X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUxMTA4MDA3OSBTYWx0ZWRfXxogod00QcIgV uxzUe+g7lz3lHaOCnwEIxcVHN5gGOWoXZ4HO3AaCLusqFGOjBDLJPqo/nj5V2QcMXLdbuQ3yzeC yGjUrcMs6PFrGTOMLe+ryZ9gwyXpsEcTxMbyz3n0IVCUZDaK0PzPSuflo3MqHl/AF47x+HjBiZu mArNAPbyOFpxPmK6t3OMmQZMRf8yBdfaMub4j/NXDOoGDu+TIFDjFd0UcUIBO1SbIGQuLR4ziBm QKZoUS4BGk8Psx/eGR9wV16pq2pi96nq6FAALcmU+W/zFnBc4fK1mW5WZRQfHauKspnGi5bFOwv 5+1XmMwbTAeR1j2GWHDjDQCIJ06lgkAv+BSao8HI5bO7cvGZVJ7kRqKqyEKbJyu0lyC8wjD+V/l 2KO0TYZNxD90EkhEXnM3isnZIJT3vA== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.9,FMLib:17.12.100.49 definitions=2025-11-10_03,2025-11-06_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 adultscore=0 priorityscore=1501 bulkscore=0 impostorscore=0 suspectscore=0 lowpriorityscore=0 clxscore=1015 phishscore=0 spamscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2510240000 definitions=main-2511080079 On Fri, Nov 07, 2025 at 04:59:16PM +0100, Aleksei Nikiforov wrote: > A false-positive kmsan report is detected when running ping command. > > An inline assembly instruction 'vstl' can write varied amount of bytes > depending on value of 'index' argument. If 'index' > 0, 'vstl' writes > at least 2 bytes. > > clang generates kmsan write helper call depending on inline assembly > constraints. Constraints are evaluated compile-time, but value of > 'index' argument is known only at runtime. > > clang currently generates call to __msan_instrument_asm_store with 1 byte > as size. Manually call kmsan function to indicate correct amount of bytes > written and fix false-positive report. ... > Fixes: dcd3e1de9d17 ("s390/checksum: provide csum_partial_copy_nocheck()") > Signed-off-by: Aleksei Nikiforov > --- > arch/s390/include/asm/fpu-insn.h | 3 +++ > 1 file changed, 3 insertions(+) Applied, thanks!