From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mta1.migadu.com (out-123.mta1.migadu.com [95.215.58.123]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1FCC5449B0B for ; Fri, 9 Oct 2026 06:35:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.123 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791527721; cv=none; b=X3b0Ju2UZOZBnifX9XrC6u9cJ9uWwagufLKvCVDDUQ7hWAIaOCXuQf/O/vKAivC0n1hHUXB2I5GGwf0wmOxUnLVnmlTPOR5pYYhy+lxqJxwFq/119J2hVnecPNPiHzCZnHwuc/Te774E+KYMzQglmisw3/wRZ7XgkBIRaZo9HRE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791527721; c=relaxed/simple; bh=tfre8IQfOGlwE6Sd6ZF0/CKAPq4d3X98BZ98KEdVsDo=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=Osjw/QWPG+DGrhjiKujtISfClJkUVtk/36T2cFLngPpIXLUmBuYvqNTMztxAp19nOg5k7Fwt946/ob4/e+mkF7gEj+k6WD5pH+lJhX59lX5UJG8sm0QoyMyaqlXEg0LX0lsRkdN6vXASUWghAB0XkT0y8GUAyb3ZPOfZNyslhEk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=RD7OVw1p; arc=none smtp.client-ip=95.215.58.123 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) header.d=linux.dev header.i=@linux.dev header.b="RD7OVw1p" X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=tfre8IQfOGlwE6Sd6ZF0/CKAPq4d3X98BZ98KEdVsDo=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1791527716; v=1; x=1792132516; b=RD7OVw1p3g/fZrB+c6jIv99zK9knIbVlVoj8N7B2zOzL+7Vo9ldkQoPk/fZN5iTjLIUKn86L j59RoYV5EpKrDYaJz7ST/CAasyDSYfi2mHC4eiT0mv9W+wFsPvd16Y8Jx2uHf2xwYZXMtvcUTse aWsBoFmobaJyuuoIY6FVeROU= X-Envelope-To: linux-kernel@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id 20cf8800623ca6ae; Fri, 09 Oct 2026 06:35:12 +0000 X-Mizu-Trace-ID: 20cf8800623ca6ae X-Migadu-Flow: FLOW_OUT From: Hao Ge To: Suren Baghdasaryan , 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 Cc: Hao Ge , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, linux-mm@kvack.org Subject: [RFC PATCH 0/4] mm/vmalloc: make the mapping functions undo their partial mappings Date: Fri, 9 Oct 2026 14:36:15 +0800 Message-Id: <20261009063619.112313-1-hao.ge@linux.dev> X-Mailer: git-send-email 2.25.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit __vmap_pages_range_noflush() and friends can install some PTEs before failing and leave them mapped, and the kernel callers do not agree on who cleans them up. pcpu_map_pages() and kmsan_ioremap_page_range() roll back what they mapped before the failure, while vm_module_tags_populate() and the __GFP_NOFAIL retry loop in __vmalloc_area_node() rely on the mapping functions cleaning up and do not call anything like vunmap_range() themselves. When the same range is mapped again, the attempt hits the leftovers and fails, with a BUG() in vmap_pte_range() for huge mappings and a warning on the small-page path. This moves the rollback into the mapping functions. A failed vmap leaves nothing mapped, and the callers no longer clean up after it. Patch 1 is the KMSAN part. The shadow and the origin of a range are mapped by two separate calls, so the rollback there has to cover both. Patch 2 adds it to __vmap_pages_range_noflush() and vmap_page_range(). Patches 3 and 4 drop the powerpc and percpu cleanups that are not needed anymore. Hao Ge (4): mm/kmsan: undo the shadow mapping when the origin mapping fails mm/vmalloc: undo partial mappings inside the mapping functions powerpc: drop redundant unmaps of failed vmap mappings mm/percpu: stop unmapping the CPU that failed to map arch/powerpc/kernel/isa-bridge.c | 5 ++-- arch/powerpc/kernel/pci_64.c | 4 +-- mm/kmsan/shadow.c | 4 +++ mm/percpu-vm.c | 5 ++-- mm/vmalloc.c | 44 +++++++++++++++++++++++--------- 5 files changed, 42 insertions(+), 20 deletions(-) -- 2.25.1