From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mta1.migadu.com (out-122.mta1.migadu.com [95.215.58.122]) (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 0AE6A47F78F for ; Mon, 19 Oct 2026 05:44:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.122 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792388704; cv=none; b=t9RD7+XH6hDLVsaM0zcQHAPwWlyEcSxG0C4OmEYo0UGHCO1q8KZ8uOEFR8blBUeXPDSMhxMk3ujFOmm9odRgdCyMrsex3bVytGwzcE5lfr4N3Z6Ej2pQYmpcs5Y6c7h4jStDQxDjX1tEk+uMX77a7WbxD2fbxh32OvdNN7hUjN4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792388704; c=relaxed/simple; bh=/fcqj4m3aIuWshJpvmCFywqs73fNC8e2m8IxJm9UhVM=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=gM9ZCwg66EnxTHVxvMDrsz/QTBvy0GGVh+3L7PagAktlqVknkWkIQB16koF4phvzARLnN2C8hQm7HqRnSM9Mqvx9SixxzVFK2KdOL1kWrRuG3gfNRpp1Qo5/2a495b0ia8FxOtaOBWrATNqjUCH8KkWpu1WGCKjwa5bQVS/ka/w= 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=L1iXzGB8; arc=none smtp.client-ip=95.215.58.122 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="L1iXzGB8" X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=/fcqj4m3aIuWshJpvmCFywqs73fNC8e2m8IxJm9UhVM=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1792388661; v=1; x=1792993461; b=L1iXzGB8MgXBJes32c8pUMkR6QGc495686Fb3M4e/WS4kl432MCwRFb90MraL3UY52FsSOdB kg8gX69i2gxRtg4dzsUOEgHN7DI38ImxPA56Rx43onDahWkaAEn84BOga3EodVgkHd92FLAgw32 ChH/tXF598lC+v7R4/pau8RA= X-Envelope-To: linux-kernel@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id c488493aed6b46f9; Mon, 19 Oct 2026 05:44:21 +0000 X-Mizu-Trace-ID: c488493aed6b46f9 X-Migadu-Flow: FLOW_OUT From: Hao Ge To: Suren Baghdasaryan , Uladzislau Rezki , 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 Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, linux-mm@kvack.org, Hao Ge Subject: [PATCH v2 0/5] mm/vmalloc: make the mapping functions undo their partial mappings Date: Mon, 19 Oct 2026 13:45:25 +0800 Message-Id: <20261019054531.87652-1-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. After discussing with Suren and Ulad [1], we move the rollback into the mapping functions. A failed vmap leaves nothing mapped, and the callers no longer clean up after it. [1] https://lore.kernel.org/all/20260915070001.113559-3-hao.ge@linux.dev/ 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 is its disabled-KMSAN counterpart. Patch 3 adds the rollback to __vmap_pages_range_noflush() and vmap_page_range(). Patches 4 and 5 drop the powerpc and percpu cleanups that are not needed anymore. Changes since v1: - Add patch 2. Sashiko reported that an empty range that hits patch 3's WARN_ON_ONCE() trips __vunmap_range_noflush()'s BUG_ON() through kmsan_vunmap_range_noflush() when kmsan=0. Patch 2 adds the kmsan_enabled check the unmap side was missing. - Pick up Reviewed-by tags from Suren and Ulad on patches 1, 4 and 5. - Add Cc: stable to patch 3. v1 link: https://lore.kernel.org/all/20261009063619.112313-1-hao.ge@linux.dev/ Hao Ge (5): mm/kmsan: undo the shadow mapping when the origin mapping fails mm/kmsan: skip vunmap_range_noflush when KMSAN is disabled 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/hooks.c | 3 +++ mm/kmsan/shadow.c | 4 +++ mm/percpu-vm.c | 5 ++-- mm/vmalloc.c | 44 +++++++++++++++++++++++--------- 6 files changed, 45 insertions(+), 20 deletions(-) -- 2.25.1