From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A582240C03 for ; Mon, 25 Nov 2024 19:10:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732561801; cv=none; b=e11THVinffxECdlz1VBZiQ3QC6za5gXk7KiabpzQOtxr/mPWd2UTae1ZIsrI8e1XYtKyipQplqyZxtFNGh4RAATa2wIxrB7n7Yzb3H+K+juspGZwGnQssK1RziaFzcp6BtOlT6zw/AEonoD9GECO2TCjLI+dKgwIbgmiFlG+Xig= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732561801; c=relaxed/simple; bh=3DhoCcAeLdrmyCY6+dEZkc6Pgk8u7SbkBVZOSwE4VAU=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=rm57Qwuw6eeBUQG+yQzzPoyb+aZbbDTynea9PSg6zr0AiAxdXz8qvnDAb6cF4q/fxeVa2GE5dP1PmJhKVF5/2JFFQeeiFVkkZhRhVOrxemvDviSzFsqUfNgSeC+eVG2UDN/ehTGUAFaNseScg9tEUJ12KlTvCW4PDS06ymtCU0s= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 Received: by smtp.kernel.org (Postfix) with ESMTPSA id AEFC2C4CECE; Mon, 25 Nov 2024 19:09:59 +0000 (UTC) Date: Mon, 25 Nov 2024 19:09:57 +0000 From: Catalin Marinas To: Sasha Levin Cc: Linus Torvalds , Will Deacon , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Yang Shi , David Hildenbrand Subject: Re: [GIT PULL] arm64 updates for 6.13-rc1 Message-ID: References: <20241118100623.2674026-1-catalin.marinas@arm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Thanks Sasha. Adding Yang Shi (he contributed the support) and David H. On Mon, Nov 25, 2024 at 10:09:59AM -0500, Sasha Levin wrote: > On Mon, Nov 18, 2024 at 10:06:23AM +0000, Catalin Marinas wrote: > > - MTE: hugetlbfs support and the corresponding kselftests > > Hi Catalin, > > It looks like with the new feature above, LTP manages to trigger the > following warning on linus-next: > > [ 100.133691] hugefork01 (362): drop_caches: 3 > tst_hugepage.c:84: TINFO: 2 hugepage(s) reserved > tst_tmpdir.c:316: TINFO: Using /scratch/ltp-CckaqgMrC1/LTP_hug5PSMw8 as tmpdir (ext2/ext3/ext4 filesystem) > tst_test.c:1085: TINFO: Mounting none to /scratch/ltp-CckaqgMrC1/LTP_hug5PSMw8/hugetlbfs fstyp=hugetlbfs flags=0 > tst_test.c:1860: TINFO: LTP version: 20240930 > tst_test.c:1864: TINFO: Tested kernel: 6.12.0 #1 SMP PREEMPT @1732504538 aarch64 > tst_test.c:1703: TINFO: Timeout per run is 0h 02m 30s > <4>[ 100.355230] ------------[ cut here ]------------ > <4>[ 100.356888] WARNING: CPU: 0 PID: 363 at arch/arm64/include/asm/mte.h:58 copy_highpage+0x1d4/0x2d8 > <4>[ 100.359160] Modules linked in: crct10dif_ce sm3_ce sm3 sha3_ce sha512_ce sha512_arm64 fuse drm backlight ip_tables x_tables > <4>[ 100.363578] CPU: 0 UID: 0 PID: 363 Comm: hugefork01 Not tainted 6.12.0 #1 > <4>[ 100.365113] Hardware name: linux,dummy-virt (DT) > <4>[ 100.365966] pstate: 63402009 (nZCv daif +PAN -UAO +TCO +DIT -SSBS BTYPE=--) > <4>[ 100.366468] pc : copy_highpage+0x1d4/0x2d8 > <4>[ 100.366780] lr : copy_highpage+0x78/0x2d8 > <4>[ 100.367090] sp : ffff80008066bb30 > <4>[ 100.368094] x29: ffff80008066bb30 x28: ffffc1ffc3118000 x27: 0000000000000000 > <4>[ 100.369341] x26: 0000000000000000 x25: 0000ffff9ce00000 x24: ffffc1ffc3118000 > <4>[ 100.370223] x23: fff00000c47ff000 x22: fff00000c4fff000 x21: ffffc1ffc3138000 > <4>[ 100.370739] x20: ffffc1ffc3138000 x19: ffffc1ffc311ffc0 x18: ffffffffffffffff > <4>[ 100.371285] x17: 0000000000000000 x16: ffffa302fd05bcb0 x15: 0000ffff9d2fdfff > <4>[ 100.372778] x14: 0000000000000000 x13: 1ffe00001859f161 x12: fff00000c2cf8b0c > <4>[ 100.374124] x11: ffff80008066bd70 x10: ffffa302fe2a20d0 x9 : ffffa302fb438578 > <4>[ 100.374877] x8 : ffff80008066ba48 x7 : 0000000000000000 x6 : ffffa302fdbdf000 > <4>[ 100.376152] x5 : 0000000000000000 x4 : fff00000c2f239c0 x3 : fff00000c33e43f0 > <4>[ 100.376962] x2 : ffffc1ffc3138000 x1 : 00000000000000f4 x0 : 0000000000000000 > <4>[ 100.377964] Call trace: > <4>[ 100.378736] copy_highpage+0x1d4/0x2d8 (P) > <4>[ 100.379422] copy_highpage+0x78/0x2d8 (L) > <4>[ 100.380272] copy_user_highpage+0x20/0x48 > <4>[ 100.380805] copy_user_large_folio+0x1bc/0x268 > <4>[ 100.381601] hugetlb_wp+0x190/0x860 > <4>[ 100.382031] hugetlb_fault+0xa28/0xc10 > <4>[ 100.382911] handle_mm_fault+0x2a0/0x2c0 > <4>[ 100.383511] do_page_fault+0x12c/0x578 > <4>[ 100.384913] do_mem_abort+0x4c/0xa8 > <4>[ 100.385397] el0_da+0x44/0xb0 > <4>[ 100.385775] el0t_64_sync_handler+0xc4/0x138 > <4>[ 100.386243] el0t_64_sync+0x198/0x1a0 > <4>[ 100.388759] ---[ end trace 0000000000000000 ]--- It looks like this can trigger even if the system does not use MTE. The warning was introduced in commit 25c17c4b55de ("hugetlb: arm64: add mte support") and it's supposed to check whether page_mte_tagged() is called on a large folio inadvertently. But in copy_highpage(), if the source is a huge page and untagged, it takes the else path with the page_mte_tagged() check. I think something like below would do but I haven't tried it yet: diff --git a/arch/arm64/mm/copypage.c b/arch/arm64/mm/copypage.c index 87b3f1a25535..ef303a2262c5 100644 --- a/arch/arm64/mm/copypage.c +++ b/arch/arm64/mm/copypage.c @@ -30,9 +30,9 @@ void copy_highpage(struct page *to, struct page *from) if (!system_supports_mte()) return; - if (folio_test_hugetlb(src) && - folio_test_hugetlb_mte_tagged(src)) { - if (!folio_try_hugetlb_mte_tagging(dst)) + if (folio_test_hugetlb(src)) { + if (!folio_test_hugetlb_mte_tagged(src) || + !folio_try_hugetlb_mte_tagging(dst)) return; /* -- Catalin