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Mon, 26 Oct 2026 08:02:51 +0000 X-Mizu-Trace-ID: 5dcbb4fe83952587 X-Migadu-Flow: FLOW_OUT From: Hao Ge To: Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin , "Christophe Leroy (CS GROUP)" , "Ritesh Harjani (IBM)" , Shrikanth Hegde , Alexander Potapenko , Marco Elver , Dmitry Vyukov , Andrew Morton , Dennis Zhou , Tejun Heo , Christoph Lameter , Uladzislau Rezki , Hao Ge , Suren Baghdasaryan , Dev Jain Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, linux-mm@kvack.org, Sashiko Subject: [PATCH v3 03/10] mm/vmalloc: clamp an unaligned range in vunmap_pte_range() Date: Mon, 26 Oct 2026 16:03:22 +0800 Message-Id: <20261026080329.140244-4-hao.ge@linux.dev> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20261026080329.140244-1-hao.ge@linux.dev> References: <20261026080329.140244-1-hao.ge@linux.dev> X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , Precedence: list X-Archived-By: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_PASS, SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 commit a739e6b557af ("mm: vmalloc: WARN_ON if mapping size is not PAGE_SIZE aligned") made vmap_pte_range() warn and bail out when the size is not a multiple of PAGE_SIZE. That loop steps in page multiples and stops only at addr == end; with an unaligned size addr never lands on end, so the loop cannot terminate and walks off the end of the page table. vunmap_pte_range() has the same loop without any guard, so an unaligned range would clear PTEs past end without ever stopping, walking off the end of the page table. Add the check there too. The range is clamped down to the last full page rather than dropped, and the loop is skipped when nothing is left, so a buggy caller still gets its PTEs cleared as far as they go. Reported-by: Sashiko Signed-off-by: Hao Ge --- mm/vmalloc.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 44e0eb32708f..7131f60d1a8e 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -393,6 +393,11 @@ static void vunmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end, pte_t ptent; unsigned long size = PAGE_SIZE; + if (WARN_ON_ONCE(!PAGE_ALIGNED(end - addr))) + end = addr + PAGE_ALIGN_DOWN(end - addr); + if (end == addr) + return; + pte = pte_offset_kernel(pmd, addr); lazy_mmu_mode_enable(); -- 2.25.1