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Thu, 6 Nov 2025 16:09:07 GMT Received: from smtpav05.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 468EE20040; Thu, 6 Nov 2025 16:09:07 +0000 (GMT) Received: from smtpav05.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 6459120043; Thu, 6 Nov 2025 16:09:06 +0000 (GMT) Received: from li-26e6d1cc-3485-11b2-a85c-83dbc1845c5e.ibm.com.com (unknown [9.111.24.158]) by smtpav05.fra02v.mail.ibm.com (Postfix) with ESMTP; Thu, 6 Nov 2025 16:09:06 +0000 (GMT) From: Aleksei Nikiforov To: Alexander Potapenko Cc: Marco Elver , Dmitry Vyukov , Andrew Morton , kasan-dev@googlegroups.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , Thomas Huth , Juergen Christ , Ilya Leoshkevich , Aleksei Nikiforov Subject: [PATCH 1/2] instrumented.h: Add function instrument_write_after Date: Thu, 6 Nov 2025 17:08:46 +0100 Message-ID: <20251106160845.1334274-4-aleksei.nikiforov@linux.ibm.com> X-Mailer: git-send-email 2.43.7 In-Reply-To: <20251106160845.1334274-2-aleksei.nikiforov@linux.ibm.com> References: <20251106160845.1334274-2-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-Transfer-Encoding: quoted-printable X-TM-AS-GCONF: 00 X-Authority-Analysis: v=2.4 cv=StmdKfO0 c=1 sm=1 tr=0 ts=690cc828 cx=c_pps a=bLidbwmWQ0KltjZqbj+ezA==:117 a=bLidbwmWQ0KltjZqbj+ezA==:17 a=6UeiqGixMTsA:10 a=VkNPw1HP01LnGYTKEx00:22 a=VnNF1IyMAAAA:8 a=KOBABV2IKOkdypTAImUA:9 a=cPQSjfK2_nFv0Q5t_7PE:22 X-Proofpoint-ORIG-GUID: wsqpo0y6lQa7s9mUgKxY6TctUwToHVni X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUxMTAxMDAxOCBTYWx0ZWRfX7jgjMaG+XyZ8 mThr2JYAcbWr0jgLh7hdJxD6YOimrAM+XG5dJiU0u4CPphdKdoI7caEJL71U/VpnjotTaZtOnbd OcJg9y1xzEnJD+Ehkgrp/+e7d6B/l4RUwFbplfBctghdzgVEFdn+ZjfHnVLWkOpZCoYPeBlVjsA UDpfU90jbCNps5+SnuacrBu8RsktfOxDycQidVkiOPOKJR8emqoKBiG4x3cix3ytROGpbJHdaxX nJvWGhbiWr6n+zsh3DjqhIxyKwbdxzg5aJG1jHTRy5bC2jjbLexTu4Mmv24mAoQQ1tERVkwtPvD bNo7Q4iQr9Cg8DvV+DWYcBNBD2GwjpfwlmykT1WdjoatAzkaddngjw4I1ybTFOiE74ZyJoEPIV/ EuS2J9r3JLpENr1OdNdyGp+G8o8ypQ== X-Proofpoint-GUID: RQXdUhJfyyG6VwdC6vI3fgqe0m3GUW_M 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=2025-11-06_03,2025-11-06_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 phishscore=0 impostorscore=0 priorityscore=1501 malwarescore=0 clxscore=1015 adultscore=0 bulkscore=0 lowpriorityscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2510240000 definitions=main-2511010018 Content-Type: text/plain; charset="utf-8" clang generates call to __msan_instrument_asm_store with size calculated based on inline asm constraints. It looks like there's no way to properly write constraint for var-size memory write and make clang generate __msan_instrument_asm_store call based on runtime-obtained size. Implement instrument_write_after similar to instrument_write and instrument_copy_from_user_after to manually fix kmsan behaviour in such cases. Signed-off-by: Aleksei Nikiforov --- include/linux/instrumented.h | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/include/linux/instrumented.h b/include/linux/instrumented.h index 711a1f0d1a73..a498d914a8b0 100644 --- a/include/linux/instrumented.h +++ b/include/linux/instrumented.h @@ -41,6 +41,20 @@ static __always_inline void instrument_write(const volat= ile void *v, size_t size kcsan_check_write(v, size); } =20 +/** + * instrument_write_after - instrument regular write access + * @v: address of access + * @size: size of access + * + * Instrument a regular write access. The instrumentation should be insert= ed + * after the actual write happens. + */ +static __always_inline void instrument_write_after(const volatile void *v, + size_t size) +{ + kmsan_unpoison_memory((const void *)v, size); +} + /** * instrument_read_write - instrument regular read-write access * @v: address of access --=20 2.43.7