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Tue, 10 Nov 2026 11:24:32 +0000 X-Mizu-Trace-ID: 272fed88d5b8e528 X-Migadu-Flow: FLOW_OUT From: Hao Ge To: Uladzislau Rezki , Dev Jain , Suren Baghdasaryan , Andrew Morton , Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin , "Christophe Leroy (CS GROUP)" , "Ritesh Harjani (IBM)" , Shrikanth Hegde , Alexander Potapenko , Marco Elver , Dmitry Vyukov , Dennis Zhou , Tejun Heo , Christoph Lameter Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, linux-mm@kvack.org, Hao Ge , stable@vger.kernel.org Subject: [PATCH v4 1/9] mm/kmsan: undo the shadow mapping when the origin mapping fails Date: Tue, 10 Nov 2026 19:25:38 +0800 Message-Id: <20261110112546.261415-2-hao.ge@linux.dev> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20261110112546.261415-1-hao.ge@linux.dev> References: <20261110112546.261415-1-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 kmsan_vmap_pages_range_noflush() first maps the shadow pages and then the origin pages. If the second mapping fails, the first one is left mapped, and the callers do not roll it back. The next vmap of the same metadata range hits the stale PTEs again and fails with a WARN_ON() and -EBUSY in vmap_pages_pte_range(). Undo the shadow mapping on that error path, the same way kmsan_ioremap_page_range() cleans up after a partial failure. __vunmap_range_noflush() only clears the PTEs; nothing has touched the shadow mapping, so no TLB flush is needed. Fixes: 47ebd0310e89 ("mm: kmsan: handle alloc failures in kmsan_vmap_pages_range_noflush()") Cc: stable@vger.kernel.org Reviewed-by: Suren Baghdasaryan Reviewed-by: Dev Jain Signed-off-by: Hao Ge --- mm/kmsan/shadow.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/mm/kmsan/shadow.c b/mm/kmsan/shadow.c index 0c88d89bf0d6..2166086d3dc3 100644 --- a/mm/kmsan/shadow.c +++ b/mm/kmsan/shadow.c @@ -258,6 +258,10 @@ int kmsan_vmap_pages_range_noflush(unsigned long start, unsigned long end, o_pages, page_shift); kmsan_leave_runtime(); if (mapped) { + /* Undo the shadow mapping set up above. */ + kmsan_enter_runtime(); + __vunmap_range_noflush(shadow_start, shadow_end); + kmsan_leave_runtime(); err = mapped; goto ret; } -- 2.25.1