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Mon, 17 Aug 2026 11:33:02 +0000 (GMT) Received: from tuxmaker.boeblingen.de.ibm.com (unknown [9.87.85.9]) by smtpav03.fra02v.mail.ibm.com (Postfix) with SMTP; Mon, 17 Aug 2026 11:33:02 +0000 (GMT) Received: by tuxmaker.boeblingen.de.ibm.com (Postfix, from userid 55669) id 4A9F41615E3; Mon, 17 Aug 2026 13:33:02 +0200 (CEST) From: Alexander Gordeev To: Gerald Schaefer , Heiko Carstens , Christian Borntraeger , Vasily Gorbik , Claudio Imbrenda , Andrey Ryabinin Cc: linux-s390@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com Subject: [PATCH v7 4/4] s390/mm: Lazy MMU mode sanitizer Date: Mon, 17 Aug 2026 13:33:02 +0200 Message-ID: <064436ca2fcc3221f12a37acd0a41d995a794cf7.1786956464.git.agordeev@linux.ibm.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: References: 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-Proofpoint-Reinject: loops=2 maxloops=12 X-Authority-Analysis: v=2.4 cv=OfaoyBTY c=1 sm=1 tr=0 ts=6a82f173 cx=c_pps a=bLidbwmWQ0KltjZqbj+ezA==:117 a=bLidbwmWQ0KltjZqbj+ezA==:17 a=Sv0fKeRqtYgA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=RzCfie-kr_QcCd8fBx8p:22 a=VnNF1IyMAAAA:8 a=DuHJb5c9rUSq-GGRdagA:9 X-Proofpoint-Spam-Info: AW1haW4tMjYwODE3MDA4NyBTYWx0ZWRfX/F6hRpjEFYcG b2EKkTZ1UshVTNvaYejVDVzsIiH6v03MoggxVV/PN50hr1mCBJ7CaKxBmrmiuEQjxBOwb54+2tp lCJ2wBy+TpKqngSZWO4E9/nrxqFhkmU= X-Proofpoint-GUID: dY7S0-hVddtmiyTGPRj2gkH2IcX9yDWG X-Proofpoint-ORIG-GUID: NlL45JyIS0IkwGwb4bRlbgWKq2rZGFzy X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwODE3MDA4NyBTYWx0ZWRfXz0XKPB/T+VdT WLVzTc4RdKa363ytu9yJj+uBgKXWDUHWlOJGGTET3zGzEJ79qldEmorLO8jMivk+VL4RxjCoj0n OVOQSyetzW0woAXie+ZxH2P522PlPTO6+otTbZIEglCmWS09LBSBoevc3iO2b0L5va1DhTBZ8qh Fb2iA4JfPRiWKIN+QtbsfWVvI62fSG4tafP9Be1CPwsg6NKKhtuLokKhapS4+TzCBA+M2UsyN80 dwQpFR+UxfxGuB1xemf0QhdS6VdtF/zR6zF8jq3Xan/Vtu1mIuafJCn8at0Nh6ldgzIuYKFsXTb 96tCpov5W7rryNPmlR1eXM4/XNJ9TybCGT92jqSGo5GPaRQh+QpJn0t0I2/5HhFkk0pCkHme5Vz khcdUVAPlhW0hang7m3xWiNOwk4N7DxELPqtmDA8r25I3QFGZ2uZyTUFFG+RTsiKpQWsgqcdotX aIan644huX/rjukai4Q== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-08-16_06,2026-08-12_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 suspectscore=0 adultscore=0 clxscore=1015 lowpriorityscore=0 impostorscore=0 malwarescore=0 bulkscore=0 phishscore=0 priorityscore=1501 spamscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2608170087 Detect PTE entries access in lazy MMU mode by means other than set_pte() and ptep_get() primitives, which would be a read hazard. The access to kasan shadow memory from ptep_get_lockless() mistakenly hits invalid access in case a concurrent lazy MMU access to the same PTE is happening. To avoid that disable instrumentation for ptep_get_lockless() altogether. Suggested-by: Ilya Leoshkevich Signed-off-by: Alexander Gordeev --- arch/s390/include/asm/pgtable.h | 6 ++++++ arch/s390/mm/lazy_mmu.c | 27 +++++++++++++++++++++++---- 2 files changed, 29 insertions(+), 4 deletions(-) diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgta= ble.h index bf54202a0630..1e8a79989ed6 100644 --- a/arch/s390/include/asm/pgtable.h +++ b/arch/s390/include/asm/pgtable.h @@ -1049,6 +1049,12 @@ static inline void set_pte(pte_t *ptep, pte_t pte) __set_pte(ptep, pte); } =20 +#define ptep_get_lockless ptep_get_lockless +static inline __no_sanitize_address pte_t ptep_get_lockless(pte_t *ptep) +{ + return READ_ONCE(*ptep); +} + static inline pte_t __ptep_get(pte_t *ptep) { return READ_ONCE(*ptep); diff --git a/arch/s390/mm/lazy_mmu.c b/arch/s390/mm/lazy_mmu.c index 002ee766b391..7e3a4115ea04 100644 --- a/arch/s390/mm/lazy_mmu.c +++ b/arch/s390/mm/lazy_mmu.c @@ -63,10 +63,13 @@ static int invalidate_pte_range(struct mm_struct *mm,= unsigned long addr, } =20 static void set_pte_range(struct mm_struct *mm, unsigned long addr, - pte_t *ptep, pte_t *end, pte_t *cache) + pte_t *start, pte_t *end, pte_t *cache) { - int i, nr_ptes; + int nr_ptes, nr_total =3D end - start; + pte_t *ptep =3D start; + int i; =20 + kasan_unpoison_pte(start, nr_total); while (ptep < end) { nr_ptes =3D invalidate_pte_range(mm, addr, ptep, end); =20 @@ -77,6 +80,7 @@ static void set_pte_range(struct mm_struct *mm, unsigne= d long addr, =20 addr +=3D nr_ptes * PAGE_SIZE; } + kasan_poison_pte(start, nr_total); } =20 static void enter_ipte_norange(void) @@ -98,6 +102,7 @@ static void enter_ipte_range(struct mm_struct *mm, unsigned long addr, unsigned long end, pte_t *pte) { struct ipte_range *range; + unsigned int nr_ptes; =20 if (!test_facility(13)) return; @@ -117,6 +122,9 @@ static void enter_ipte_range(struct mm_struct *mm, range->base_end =3D end; range->base_pte =3D pte; =20 + nr_ptes =3D (range->base_end - range->base_addr) / PAGE_SIZE; + kasan_poison_pte(range->base_pte, nr_ptes); + local_bh_enable(); } =20 @@ -125,6 +133,7 @@ static void leave_ipte_range(void) pte_t *ptep, *start, *start_cache, *cache; unsigned long start_addr, addr; struct ipte_range *range; + unsigned int nr_ptes; int start_idx; =20 if (!test_facility(13)) @@ -163,6 +172,9 @@ static void leave_ipte_range(void) range->end_pte =3D NULL; =20 done: + nr_ptes =3D (range->base_end - range->base_addr) / PAGE_SIZE; + kasan_unpoison_pte(range->base_pte, nr_ptes); + range->mm =3D NULL; range->base_addr =3D 0; range->base_end =3D 0; @@ -244,10 +256,17 @@ static void __ipte_range_set_pte(struct ipte_range = *range, pte_t *ptep, pte_t pt static pte_t __ipte_range_ptep_get(struct ipte_range *range, pte_t *ptep= ) { unsigned int idx =3D ptep - range->base_pte; + pte_t pte; =20 lockdep_assert_preemption_disabled(); - if (pte_val(range->cache[idx]) =3D=3D PTE_POISON) - return __ptep_get(ptep); + if (pte_val(range->cache[idx]) =3D=3D PTE_POISON) { + kasan_unpoison_pte(ptep, 1); + pte =3D __ptep_get(ptep); + kasan_poison_pte(ptep, 1); + + return pte; + } + return range->cache[idx]; } =20 --=20 2.53.0