From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=91.218.175.193 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794309915; b=5lxKGzkRol4ogigrUNiLy0FbCaPNEpLJ+LE/nJzDJMMkDiIkmpJWKErkEvdIdouDFcSt PS7A2OBtGoT5AAeZuPtbq86FooA1dnMTOLq8Asu/Ii52Y9tqwtM1t2gpCm6cS5cW9UTLI M25towK6Z72kjWGQi0WVkaKvlsrDxW6cH1CQPnkEIEAEcur5xDi3Qw7X4qOyytiAk+joO AvbX0efARx3khNTebUhp1Omk9D0xvwSv2AoEl5kRJzC7Y2OHwIcwE5tadfEwArRVLl403 fZVlMezSNRFlmHjHutRgCrBnIyVATdnwF8DZRXda6AIlGSIIBN+7QWL6Kz1qJO6V3Mw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794309915; h=DMARC-Filter:X-Envelope-To:DKIM-Signature:X-Envelope-To:Received: X-Mizu-Trace-ID:X-Migadu-Flow:From:To:Cc:Subject:Date:Message-Id: X-Mailer:In-Reply-To:References:MIME-Version: Content-Transfer-Encoding; bh=njIoOXK5zMREOncg8mUAQGqPEShsE5xs29xDkWFtyUU=; b=LosghG204nfk4TUsqv2WPwmsUEoZFmFslgwdWP4GtFva0xws6f4iwk0BTw6OPbZOhN4n +NmIKWmRvP6vILRNcBJ0GKwbzn+ujTd36MC4H/SRVjQwzKgUnPNwSihdoIp58qBQHfO2p NqO97bdzu5FR+ehdWTJDotpsOqvMbw/2VFJaxfLASVSZdVfqwpeL7/l5fL1q1+vtcZWae pTNwVYBpVWPwi6+5lY9EGfQyhshCJEs642s4AqDq/HMdqQUDOxtmKJUDsEkruPL4+8SZf wMtCGkWwAYZhpl3GE9PshuC2hIP8SnmQ+zbieaAnWNY49HRvgB159D2XUnz0ymSfcxg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b="mVkWfYh/"; arc=none smtp.remote-ip=91.218.175.193 Received: from mta0.migadu.com (out-193.mta0.migadu.com [91.218.175.193]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1C5CD60A262F for ; Tue, 10 Nov 2026 11:25:14 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 1C5CD60A262F Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=mVkWfYh/ X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=BPShZdqjxGXzG9YjR46DA5wDrW3cgTzpgUAq+Dua6mc=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1794309913; v=1; x=1794914713; b=mVkWfYh/OU5ocR0W3SIgvgFGay1eXuZ9K2ZVcborArx5MMPEOCDYFyeFOxuvPOfLou+64Lbj NxviIlOtEWv4pnOnogTcpp3NFs6KhEcTsaL6ycgwbASbu3WK9k8ORbYH9DHGuAFwa6g6CJimA+3 WU9vvPNnJDjYBbYQqi7Xo5Z8= X-Envelope-To: linux-kernel@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id aaa1849df80259f7; Tue, 10 Nov 2026 11:25:10 +0000 X-Mizu-Trace-ID: aaa1849df80259f7 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 , Sashiko Subject: [PATCH v4 6/9] mm/vmalloc: only flush the cache after the vmap succeeded Date: Tue, 10 Nov 2026 19:25:43 +0800 Message-Id: <20261110112546.261415-7-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: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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 | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 0565cbfe325c..3f98056f8c7e 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -369,10 +369,12 @@ 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); + if (!err) + flush_cache_vmap(addr, end); + return err; } @@ -758,7 +760,9 @@ 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); - flush_cache_vmap(addr, end); + if (!err) + flush_cache_vmap(addr, end); + return err; } -- 2.25.1