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 6E96738911E for ; Fri, 8 May 2026 11:53:49 +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=1778241229; cv=none; b=MveOE17f+gDm4+kyXeBLOHM77X+bKZ9ISxzqW7zWNt5QzLVvi52r8ccG9Jc9HBTCJfWKIJCV9Z98he1GYCC0vACZGiCPGe9nO+GXl1PtOFC8bCdSaD+BLV4Zoqajv75KU4ggN2CuXBNxEBwMalp6UxEcQ1ZAdY3tJQ+D71GsRRk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778241229; c=relaxed/simple; bh=xVjGIZ5IQRdyjqPF7MNwq83MBWf3864Rm+exjqz/+zM=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=GKRXmKHJhB+AvMuivbz9nCkgj6Foh1Tw8oiPh/TmVFx6yO0fD2nKUZVNqyDMZ+l4Mj1cStFekW1551NobPzDxi9wqul8PobZgRpB02gJxuzKkNdF6TRI57TEizJmFZmHBPxx9C2lXxGIRJRWmt2DB6ZKhSCCSEdwsBLJUL+eZF8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=jD/Q8+a8; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="jD/Q8+a8" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 630CAC2BCB8; Fri, 8 May 2026 11:53:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1778241229; bh=xVjGIZ5IQRdyjqPF7MNwq83MBWf3864Rm+exjqz/+zM=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=jD/Q8+a8K/ft4wOZk8mdokkpVL/c/gQDZFTCQS5ez0XSneYmxlfRAtaMwNNaQPGKy zZEMzW3kW9/4iX7MGKRxUwnQgy0O/TEf42C/hioE6OxLz9jB7bNk8XyJ5Ub1Wq9JHq fLiGzHKIa9jLa3f/feUEcbCXU/PKQ8fSXXcH9SbH8z8T0L28ee8HF7DoWl9f1bvIVa adtf/6zkYF/Q6vWvlHodOxPhFA2fSjRjgpBVtJ6dAKUenY0rhYIoMmVwq6XdFZ5mm0 ebfN41jJI5G5vY4XDwd2/zaX30DZAsnMhRrIdksFrwKOGitKtz/LvZE5HdjRgPlmnn JLatZ7qJEknNw== Message-ID: <10e4565a-b416-45d9-a8b0-cd32532b2630@kernel.org> Date: Fri, 8 May 2026 13:53:43 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: "alloc_tag was not set" when running mm/ksft_hmm.sh To: Zenghui Yu , linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: jgg@ziepe.ca, leon@kernel.org, Andrew Morton , ljs@kernel.org, liam@infradead.org, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com, Alistair Popple References: From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 5/6/26 17:42, Zenghui Yu wrote: > Hi all, > > Running mm/ksft_hmm.sh triggers the following splat: > > ------------[ cut here ]------------ > alloc_tag was not set > WARNING: ./include/linux/alloc_tag.h:164 at ___free_pages+0x2a0/0x2d0, > CPU#5: hmm-tests/2020 > Modules linked in: test_hmm rfkill drm backlight fuse > CPU: 5 UID: 0 PID: 2020 Comm: hmm-tests Kdump: loaded Not tainted > 7.1.0-rc2-00099-gadc1e5c6203c-dirty #285 PREEMPT > Hardware name: QEMU QEMU Virtual Machine, BIOS > edk2-stable202408-prebuilt.qemu.org 08/13/2024 > pstate: 61400005 (nZCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--) > pc : ___free_pages+0x2a0/0x2d0 > lr : ___free_pages+0x2a0/0x2d0 > sp : ffff80008345b530 > x29: ffff80008345b530 x28: ffff80008345b700 x27: ffffffffbfff8040 > x26: ffff0000c41cb360 x25: ffff0000c0c64008 x24: ffff800081aae400 > x23: 05ffff0000000200 x22: 0000000000000000 x21: 0000000000000000 > x20: fffffdffc5f20040 x19: 0000000000000000 x18: fffffffffffe7c78 > x17: 0000000000000000 x16: 0000000000000000 x15: fffffffffffe7c98 > x14: 00000000000001d1 x13: ffff8000818f3d58 x12: 0000000000000573 > x11: fffffffffffe7c98 x10: ffff80008194bd58 x9 : 3ffffffffffff000 > x8 : ffff8000818f3d58 x7 : ffff80008194bd58 x6 : 0000000000000000 > x5 : ffff0001fedb1088 x4 : 0000000000000001 x3 : 0000000000000000 > x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff0000c7f58000 > Call trace: > ___free_pages+0x2a0/0x2d0 (P) > __free_pages+0x14/0x20 > dmirror_devmem_free+0x13c/0x158 [test_hmm] > free_zone_device_folio+0x144/0x1e4 > __folio_put+0x124/0x130 > free_folio_and_swap_cache+0xa8/0xcc > __folio_split+0x664/0x7fc > split_folio_to_list+0x50/0x5c > migrate_vma_split_folio+0x13c/0x25c > migrate_vma_collect_pmd+0xed4/0xf68 > walk_pgd_range+0x598/0x9a0 > __walk_page_range+0x90/0x1a0 > walk_page_range_mm_unsafe+0x194/0x20c > walk_page_range+0x20/0x2c > migrate_vma_setup+0x18c/0x224 > dmirror_devmem_fault+0x188/0x2b8 [test_hmm] > do_swap_page+0x1458/0x185c > __handle_mm_fault+0x85c/0x1ba0 > handle_mm_fault+0xb0/0x290 > do_page_fault+0x1f8/0x6f8 > do_translation_fault+0x60/0x6c > do_mem_abort+0x44/0x94 > el0_da+0x30/0xdc > el0t_64_sync_handler+0xd0/0xe4 > el0t_64_sync+0x198/0x19c > ---[ end trace 0000000000000000 ]--- > lib/test_hmm.c:705 module test_hmm func:dmirror_devmem_alloc_page has > 16744448 allocated at module unload > > > It was tested on kernel built with arm64's virt.config and > > +CONFIG_ZONE_DEVICE=y > +CONFIG_DEVICE_PRIVATE=y > +CONFIG_TEST_HMM=m > +CONFIG_MEM_ALLOC_PROFILING=y > +CONFIG_MEM_ALLOC_PROFILING_DEBUG=y I assume there is a weird interaction between alloc tags and simulated ZONE_DEVICE memory in test_hmm.c @Alistair, any idea? -- Cheers, David