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 D45213B19D9; Tue, 21 Jul 2026 05:40:02 +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=1784612404; cv=none; b=c9MUIDxRxg9Vq/jKsQuYkv/cUAJvBJG0mrM7eZIaUYUFP32yX6pH77tvM+smup/FmF24mXkuQ5qnEf83fkjhlzzA7qJVp5/MZCu/v8ZEeiqvkVla5eeD4xDfhj25+216K/WPHYRH2B8ff4bmCT6mJRgSOb61KwQtf9Bjqy7quA8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784612404; c=relaxed/simple; bh=c4M3jRlqtSx7k4Fs9CzNUbTBEh8/1wpB1NIh1fvqsnM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=miWF6gt3hGf4hqwehrHupRHscfWDTgZ6MbTzGLc5UrcvU/N/LflEC2w2ktpx2ddJXVsUC4P1t1qzAeOpZIj7OSPjbLBp11xSizVQU9gLt+Z3ohZmk+CGqgjNQrohY4MYjwoXiTxSKfzGttlPUsYvBEQHk1EU0howvGf6Bups298= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=OCpBk2wW; 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="OCpBk2wW" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8C3781F000E9; Tue, 21 Jul 2026 05:40:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1784612402; bh=PuflvRpV0/G/rMKVpE40NhiuuK6VGHdPh4LWwMCVrYw=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=OCpBk2wW3HItgx7By34nRekSmYcmte2f80VOSPeAlopjTxJN6bme18tUQyLvcIcRP rvTt9w2h5iDRQBjdQRT3F6Jb6UJil+bFdiBCdHLQL2O1aADrLuEZi6PXvvlH0IQ4Z9 QflsWVgPikFhjWy0R6NVqKPM7/YZZ0V6fAKDp/L0e+Kg7T1wZPWWVLTG42AKAVBV+o wp5qGevP/5eIJaZsE4Mcgn6Z4EsMcCtjdNJtXJpck3p//Y2IUsPQ6EvOUk/JzJO7a9 2Z6OYQ1OmwaYGOcRV9Ml+1ENA9n5UJLMrh2k9MrM9kE5EmXL7mxcw414wQOiK2+6Ll nT4BWvR1rlemg== From: SJ Park To: stable@vger.kernel.org Cc: damon@lists.linux.dev, Zenghui Yu , SJ Park , Andrew Morton Subject: [PATCH 7.1.y] samples/damon/mtier: fail early if address range parameters are invalid Date: Mon, 20 Jul 2026 22:39:53 -0700 Message-ID: <20260721053953.181336-1-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <2026072007-eldercare-amusing-37b4@gregkh> References: <2026072007-eldercare-amusing-37b4@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org 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 | 3 +++ 1 file changed, 3 insertions(+) diff --git a/samples/damon/mtier.c b/samples/damon/mtier.c index 775838a23d935..7f84367ad3e58 100644 --- a/samples/damon/mtier.c +++ b/samples/damon/mtier.c @@ -120,6 +120,9 @@ 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