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Mon, 26 Oct 2026 08:03:10 +0000 X-Mizu-Trace-ID: 8477b878ce637510 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 07/10] mm/vmalloc: only flush the cache after the vmap succeeded Date: Mon, 26 Oct 2026 16:03:26 +0800 Message-Id: <20261026080329.140244-8-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-Archived-By: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Queue-Id: E92B280005 X-Stat-Signature: brmam19a18mwx4nxnicttok3xhuohfhs X-Rspamd-Server: rspam01 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=ham autolearn_force=no version=4.0.1 X-HE-Tag: 1793001793-995255 X-HE-Meta: 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 VsrglOat b/C2u3LsXfD80XoLFpGI2xZ4yfouz/BGwzKz8T8RX5fZOGBOotOi2R6vwiOxUsMnuZZia7UsleJprHkK0ceS3ZxKJKbgarR9/sN1aEvRFkhTS/sVBPTFCbzDgac9CNu5noESoV1AqfkVQNilZX3fNVmvQDyXiPiErSquC31Ep1Yxsc50b6mzoMzmlCSjAM+y6dDxfssQIVnR2DnbtcZFffcwREupb95IhOlhkYMdSEcpqWQKRsTyuRCXYWr5pHvD2Ih2tJnfpzepcBvOpez0gu2QgJ2gLpTEBggLOahOZ6cVDNM/RqrEqSrVzTbsqwAkkelVse+BJ0CwgM54= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 vmap_page_range() and __vmap_pages_range() call flush_cache_vmap() before they even look at the error code. A failed mapping is never used, so the flush is pointless at best. According to the Sashiko review it is worse than pointless on UML: flush_cache_vmap() there is flush_tlb_kernel_range(), which syncs the PTEs into the host OS. Flushing a half-installed mapping therefore leaves host mappings behind for a range that was just freed again. Only flush when the mapping, and for vmap_page_range() also the KMSAN metadata, is fully set up. Reported-by: Sashiko Signed-off-by: Hao Ge --- mm/vmalloc.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 4d74144dfaff..96e15d6cfc6d 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -359,11 +359,14 @@ int vmap_page_range(unsigned long addr, unsigned long end, err = vmap_range_noflush(addr, end, phys_addr, pgprot_nx(prot), ioremap_max_page_shift); - flush_cache_vmap(addr, end); if (!err) err = kmsan_ioremap_page_range(addr, end, phys_addr, prot, ioremap_max_page_shift); - return err; + if (err) + return err; + + flush_cache_vmap(addr, end); + return 0; } int ioremap_page_range(unsigned long addr, unsigned long end, @@ -745,8 +748,11 @@ static int __vmap_pages_range(unsigned long addr, unsigned long end, int err; err = vmap_pages_range_noflush(addr, end, prot, pages, page_shift, gfp_mask); + if (err) + return err; + flush_cache_vmap(addr, end); - return err; + return 0; } /** -- 2.25.1