From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 348DE23394E; Tue, 21 Jul 2026 05:37:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784612247; cv=none; b=YbXx9fgzlwfkHJzLf0odvcCbNoPVcJzxZpRYu1F2dokO/Fy0tuU8hKMsEzuNg9HMXCl/nqQjJ5ggcbQc74V3S12+1WRuCwje3wFcoM8ZXoNamBQw+YOtwDEcFrs4tNIQvQqesWktxLcer4BfkRFkhRGEOj6018UVs4YqqJV9x4A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784612247; c=relaxed/simple; bh=Fs32/Rj+5wkyYKtsUBdarEl+Wndjy3GcwXijEqLBn5M=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=sRzVMK4dM6tsJLKQetjGfevPjsU+bTIMPREgQrqWWMc3U7iD0EoiH3FvsIAs2Vu8gzuVyV3ny6Gnb4LvTvTytPwFN4lH0RteW+1zFwBQlJ3MIvhFnjB73SP5zL2uTfXh1wXNmQT+jycYs1cUsWKRk6sgsKZ8RxWFe5yrA9bHfvA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=gLSL5hr8; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="gLSL5hr8" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BC4021F000E9; Tue, 21 Jul 2026 05:37:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1784612246; bh=RGsup1c1AD/U6aOlIhmnfWYsM4x3sjH6Ebvzt7E0ixU=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=gLSL5hr8CB43HPFhdQxoGHwJAosG4o9XRKBAZREUt3ZLvHyeO4pZYQDnlb3lXLd5w 7mMZcInyuAyOzLY9vLmcbyO+AAFI4XNIbbpPcc/pu45Az7M9XX8vtLyQ5AXpzI1gtG d8mMiCn6k/f30yyJ5gTOP7ElNzhEja8tw+XObE3zYW9AiKtKl+79MSel5NVLJD42qU Y064rx2XofN45WTnA3Kfe5YGGt6VKpUyOxx/48yUmDHkoWvOzxdHdkI+uO/0N5MibV ZKY3PFu+0jnTHAFspHlB7rgcB1uC/uSxq1VSRJHVmcGdQ4JtL1UAdkTO7DqpvRVSPB xFhRaW9uQZnjw== From: SJ Park To: stable@vger.kernel.org Cc: damon@lists.linux.dev, Zenghui Yu , SJ Park , Andrew Morton Subject: [PATCH 6.18.y] samples/damon/mtier: fail early if address range parameters are invalid Date: Mon, 20 Jul 2026 22:37:18 -0700 Message-ID: <20260721053718.177006-1-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <2026072008-humongous-quintuple-a2a9@gregkh> References: <2026072008-humongous-quintuple-a2a9@gregkh> Precedence: bulk X-Mailing-List: damon@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Zenghui Yu 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:217 at damon_new_region+0xf4/0x118, CPU#59: bash/341468 Call trace: damon_new_region+0xf4/0x118 (P) damon_set_regions+0xfc/0x3c0 damon_sample_mtier_build_ctx+0xe8/0x3a8 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 ]--- Note that the same issue can happen if detect_node_addresses is true, and node 0 or 1 is memoryless. Fix it together by checking the validity of parameters right before damon_new_region() and fail early if they're invalid. Link: https://lore.kernel.org/20260629144432.133962-1-sj@kernel.org Fixes: 82a08bde3cf7 ("samples/damon: implement a DAMON module for memory tiering") Signed-off-by: Zenghui Yu Signed-off-by: SJ Park Reviewed-by: SJ Park Cc: # 6.16.x Signed-off-by: Andrew Morton (cherry picked from commit 7746d72c64054976887928d64d2caf25c5a6dcc0) Signed-off-by: SJ Park --- samples/damon/mtier.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/samples/damon/mtier.c b/samples/damon/mtier.c index 775838a23d935..dab8fb10b617a 100644 --- a/samples/damon/mtier.c +++ b/samples/damon/mtier.c @@ -120,6 +120,8 @@ static struct damon_ctx *damon_sample_mtier_build_ctx(bool promote) addr.end = promote ? node1_end_addr : node0_end_addr; } + if (addr.start >= addr.end) + goto free_out; region = damon_new_region(addr.start, addr.end); if (!region) goto free_out; -- 2.47.3