From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7F271C77B61 for ; Mon, 24 Apr 2023 13:31:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232428AbjDXNbJ (ORCPT ); Mon, 24 Apr 2023 09:31:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59288 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232427AbjDXNaz (ORCPT ); Mon, 24 Apr 2023 09:30:55 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3A0087A81 for ; Mon, 24 Apr 2023 06:30:20 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 1B88B62339 for ; Mon, 24 Apr 2023 13:30:20 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3015EC433D2; Mon, 24 Apr 2023 13:30:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1682343019; bh=VWeaSIihX1UD1HpAC36qM6ZP2rDBKHTw1ESYWCVeS1Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Jy7sJ041zZ9e1KR9VSW4Y00BizO+s1xtZVUZbxtlG/mUFCEFAQw/aMP3h+ryOrkxo SkRME+4tEjGiN0hPL301IZOvBx3dXvfNBcYuL2YiEi2Uo5TiGUYaRwx6B3iERGoxnq wFlO9j9Djwx6Ahg/FZKZ9cHLT3GEOJTnCU6FTEZg= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, =?UTF-8?q?Lu=C3=ADs=20Mendes?= , David Gow , =?UTF-8?q?Christian=20K=C3=B6nig?= , Arunpravin Paneer Selvam , Sasha Levin Subject: [PATCH 6.2 047/110] drm: buddy_allocator: Fix buddy allocator init on 32-bit systems Date: Mon, 24 Apr 2023 15:17:09 +0200 Message-Id: <20230424131137.992320062@linuxfoundation.org> X-Mailer: git-send-email 2.40.0 In-Reply-To: <20230424131136.142490414@linuxfoundation.org> References: <20230424131136.142490414@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: David Gow [ Upstream commit 4453545b5b4c3eff941f69a5530f916d899db025 ] The drm buddy allocator tests were broken on 32-bit systems, as rounddown_pow_of_two() takes a long, and the buddy allocator handles 64-bit sizes even on 32-bit systems. This can be reproduced with the drm_buddy_allocator KUnit tests on i386: ./tools/testing/kunit/kunit.py run --arch i386 \ --kunitconfig ./drivers/gpu/drm/tests drm_buddy (It results in kernel BUG_ON() when too many blocks are created, due to the block size being too small.) This was independently uncovered (and fixed) by Luís Mendes, whose patch added a new u64 variant of rounddown_pow_of_two(). This version instead recalculates the size based on the order. Reported-by: Luís Mendes Link: https://lore.kernel.org/lkml/CAEzXK1oghXAB_KpKpm=-CviDQbNaH0qfgYTSSjZgvvyj4U78AA@mail.gmail.com/T/ Signed-off-by: David Gow Acked-by: Christian König Reviewed-by: Arunpravin Paneer Selvam Link: https://patchwork.freedesktop.org/patch/msgid/20230329065532.2122295-1-davidgow@google.com Signed-off-by: Christian König Signed-off-by: Sasha Levin --- drivers/gpu/drm/drm_buddy.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/drm_buddy.c b/drivers/gpu/drm/drm_buddy.c index 3d1f50f481cfd..7098f125b54a9 100644 --- a/drivers/gpu/drm/drm_buddy.c +++ b/drivers/gpu/drm/drm_buddy.c @@ -146,8 +146,8 @@ int drm_buddy_init(struct drm_buddy *mm, u64 size, u64 chunk_size) unsigned int order; u64 root_size; - root_size = rounddown_pow_of_two(size); - order = ilog2(root_size) - ilog2(chunk_size); + order = ilog2(size) - ilog2(chunk_size); + root_size = chunk_size << order; root = drm_block_alloc(mm, NULL, order, offset); if (!root) -- 2.39.2