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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 02841CD8C92 for ; Mon, 8 Jun 2026 15:54:30 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 4BF106B008A; Mon, 8 Jun 2026 11:54:30 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 448216B008C; Mon, 8 Jun 2026 11:54:30 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 35F126B0092; Mon, 8 Jun 2026 11:54:30 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 255186B008A for ; Mon, 8 Jun 2026 11:54:30 -0400 (EDT) Received: from smtpin18.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay06.hostedemail.com (Postfix) with ESMTP id E597B1C0EA3 for ; Mon, 8 Jun 2026 15:54:29 +0000 (UTC) X-FDA: 84857192658.18.51CB10C Received: from out-173.mta0.migadu.com (out-173.mta0.migadu.com [91.218.175.173]) by imf08.hostedemail.com (Postfix) with ESMTP id 9BD5D160016 for ; Mon, 8 Jun 2026 15:54:27 +0000 (UTC) Authentication-Results: imf08.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=rNPbqq1I; spf=pass (imf08.hostedemail.com: domain of zenghui.yu@linux.dev designates 91.218.175.173 as permitted sender) smtp.mailfrom=zenghui.yu@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1780934068; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=6e2VJEUHPiaVEzDajlyn44RRt816M9gMkmZzGYOPYKs=; b=00AVCmquW52giX9YjlkLvNYZxb1szW382RhFO3OeqivKH2tzMuSjBmIYz6OtmN3Ts4fmlt cFWvAfMQBbYF5hhkw6Rd+WT88gJdpgQfrCmKSoXWzUEl2BDJWm/7UEOl1HjQs7Wko9yHc7 /hk/iDVYDigjD+wsmljSGekp/kNdSCY= ARC-Authentication-Results: i=1; imf08.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=rNPbqq1I; spf=pass (imf08.hostedemail.com: domain of zenghui.yu@linux.dev designates 91.218.175.173 as permitted sender) smtp.mailfrom=zenghui.yu@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1780934068; b=VLdV9Wwqh5wVLVBU6SNzdKUVKkQVVr2qa+5MnJZt330suRwVK4j33Z0ylRp8gH1A9q5Td1 d899oGogrXiYa+Nd6q9WXGSbrzlS7gRgRjJG6WEMZY/2u9wjvf2OFGgXta9icKG/pjjWHl 2fV7mJw2cBouDtoO2ZMbxQ1H03hNtT8= Message-ID: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1780934065; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=6e2VJEUHPiaVEzDajlyn44RRt816M9gMkmZzGYOPYKs=; b=rNPbqq1I7hkbyj7+TSLh7GUGIafvhL/CrNoQS89F78tQY8IyKTNll6zSvfH+Sv7h+4xjkc QsF5QGVQSTsv9n0ITb3SeskKIhfABcUz1mfN7/wRz9A1OJTwv0ZfxVN0ScUi/1Ih1umJUs ubYHA+pS+iTErOxRwpTwXGJ9p1GDr1c= Date: Mon, 8 Jun 2026 23:54:13 +0800 MIME-Version: 1.0 Subject: Re: [PATCH] samples/damon/mtier: fail early if address range parameters are invalid To: SeongJae Park Cc: Zenghui Yu , damon@lists.linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, wangzhigang17@huawei.com, liqiqi23@huawei.com References: <20260608143250.69024-1-sj@kernel.org> Content-Language: en-US X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Zenghui Yu In-Reply-To: <20260608143250.69024-1-sj@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT X-Rspamd-Queue-Id: 9BD5D160016 X-Stat-Signature: djzqyjqhqa45wf74jjwnfwfircfkmi5x X-Rspam-User: X-Rspamd-Server: rspam12 X-HE-Tag: 1780934067-941926 X-HE-Meta: U2FsdGVkX1+TFXrb1CYc7/F2QhP6fNz2h3A9qcwAfZeVIJAgw3SeHFH94CCcwdV+bXsDTATUB8jvp4mkStg0JRzq9ApcaoCFPg4fuE02WAhxYnQ8u6zWLnbPNsNBpiIC5w31NGQPdNWiTj3S+AcxQe5qfJZCzuinorh/rp2GKCBJG0/zBTNxMP17zm5SKcpcOa+94ylu7no4GxL7aHin7uH80nZV7vyoI5hcnsu9qpF2O38TiEx6xKVG2RQ4uvDHS78Ewfv2Oei7bTQMJ8ndHj4ULOQgXs5cIZYXqC/QVMXos4iKdnuyCVIQO/VjHltexxfY+DQqxjcDcS/s8fBZseTjSLsIo74KWfeC20JQUipNbWQ/x+LoBcbaYVzcSFUFswQ+uG7198LjUAMKraXr9lLgXvaFZJgsUxiUU6nN7teLqe2HaNZoU4Z7BnQQoAcetQDbBzTSz/vA2/7/N5ctCg54lYFMfrUmRrRm86XUyPCA4Xgy9/F+ZYPVvNHqsLZSmMp/J8eiQHCyVt75gNbN1co3y/VaOOJyiKL0AaYmPOJB/j+v3FBEj4fFgWjoCUWIBtREsVK8LyFlisD/iNMJs8n2qEmJ1mHUBbD8JwqW8wZex5H4L7odn95PO/HiS59J74pfh6RviQu9BCQVDYlJ0J3DM73EGlPcfmXMFxB/C2sq+WOvbNxQDOPUhu1aqJpkUXD2dLC7nmBeiMssOOtT5BivK1AJU/zrlK0aKgEjlSrOltT0RlId2cQizuWe3aoznizPZh/xH2KGd+4Lof6KHrl3wYCUCr2E+AXNqWBXvI2o0IquI+zilKVvQNb0TDCc+Zxj4OmO9F1rSqTgktE6TMa54DX/nOtG0QAQ5l5uOf+J8ziFQDM5GVC0/+FvVvfj9EIZ95zIPODBPkyL9rnkYkfv7gFkLJs8O9kJKey5dvYUfWckdvNd4KbcPGnQLG/cfg5lIBjmlMN6B8BHc9k kwuHX2yA BcTT6z8Whq/TjSEBE6vDgBMVw/oxPa54yDqXg9exjUhsZtyn6pMcNiTe39lwFFAG/A6vARhT8rg3UyOEyYlw4aWlJagNH4kdxcx8o73iPuo1JSWRBebLY01nU2klyoVH4QfhKbgwqHkfMmm1HHlIqhq92lEZSx/M2nGfgY2ZqCxOqA0WENBYvJQqOhRHFUq5AqsR6OdtlJCZsy9uB3xW7QyTn5/Q4b0eJtVlf8ZnoEhiVdrk= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Hi SeongJae, On 6/8/26 10:32 PM, SeongJae Park wrote: > On Mon, 8 Jun 2026 19:15:34 +0800 Zenghui Yu wrote: > > > The comment on top of `struct damon_region` clearly says that > > > > For any use case, @ar should be non-zero positive size. > > > > which is now verified in damon_verify_new_region() if the kernel is built > > with DAMON_DEBUG_SANITY. > > > > The WARN_ONCE() can be triggered if the mtier sample module is enabled > > before node{0,1}_{start,end}_addr have been properly initialized, which is > > obviously not good. > > > > ------------[ cut here ]------------ > > start 0 >= end 0 > > WARNING: mm/damon/core.c:116 at damon_new_region+0xf0/0x118, CPU#39: bash/34144 > > Call trace: > > damon_new_region+0xf0/0x118 (P) > > damon_sample_mtier_build_ctx+0xd4/0x368 > > damon_sample_mtier_start+0x1c/0x90 > > damon_sample_mtier_enable_store+0x98/0xb0 > > param_attr_store+0xb4/0x128 > > module_attr_store+0x2c/0x50 > > sysfs_kf_write+0x58/0x90 > > kernfs_fop_write_iter+0x16c/0x238 > > vfs_write+0x2c0/0x370 > > ksys_write+0x74/0x118 > > __arm64_sys_write+0x24/0x38 > > invoke_syscall+0xa8/0x118 > > el0_svc_common.constprop.0+0x48/0xf0 > > do_el0_svc+0x24/0x38 > > el0_svc+0x54/0x370 > > el0t_64_sync_handler+0xa0/0xe8 > > el0t_64_sync+0x1ac/0x1b0 > > ---[ end trace 0000000000000000 ]--- > > > > Fix it by checking the validity of parameters right before > > damon_new_region() and fail early if they're invalid. > > Good catch, thank you for this patch. > > > > > Signed-off-by: Zenghui Yu > > --- > > samples/damon/mtier.c | 3 +++ > > 1 file changed, 3 insertions(+) > > > > diff --git a/samples/damon/mtier.c b/samples/damon/mtier.c > > index 775838a23d93..4a5d3fb12e1b 100644 > > --- a/samples/damon/mtier.c > > +++ b/samples/damon/mtier.c > > @@ -118,6 +118,9 @@ static struct damon_ctx *damon_sample_mtier_build_ctx(bool promote) > > } else { > > addr.start = promote ? node1_start_addr : node0_start_addr; > > addr.end = promote ? node1_end_addr : node0_end_addr; > > + > > + if (addr.start >= addr.end) > > + goto free_out; > > } > > Sashiko found [1] same issue can happen if detect_node_addresses is true, and > nodes 0 and 1 are both memoryless. It shouldn't be a blocker of this patch, > but fixing it together can be very simple by moving this address check to the > out of the above if block, right here. Zenghui, could you please update this > patch to do that? Yup, it's worth fixing. I will address the detect_node_addresses issue in v2. > > Also, seems this patch is based on an old tree. Could you please use > mm-new [2] as the base of your DAMON patches from next time? Ah, I'm not familiar with the development process of DAMON and I created this patch against mainline kernel. I'll re-test the whole thing on top of mm-new. Thanks for the reminder! Zenghu