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 2260619409E for ; Mon, 23 Sep 2024 08:50:41 +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=1727081442; cv=none; b=QILM1p58kRxi5Fkbx+Tmxk1dtJa9u6vuvMqyexn1knziHTBiOK1Hp/QkCnmnt0Sf9Jq7M0447Y2C6/m2RE+FRzmqph+t/fDyt1sMHqmCXC9sO0P7ToPnyan6E9JN60HPjrgbqm+6l5XgHRa3eCNWpsLjLswWcLYcbZujAnrMXXg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727081442; c=relaxed/simple; bh=XbiJTxstb2TKquC/befwcMAMjPw/EN8TCmrYDdvf5fQ=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=SqGhdYfuBu4eMwvlqd/kpTbxCBaqukomb7n1l+mFVq3VADtsFF2c3OGEaKsEaZhg8DacLc/29xGePEIkcIAMjfX1tdAUbRVgj6qXalW5qGc7pqwqQomhSxmttvQ0yxBKWQxUzNtxb0udNVjf92yYS1NQv/WzJnxei2hkbbpSFWQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=cD1t5cr6; 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="cD1t5cr6" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 71954C4CEC4; Mon, 23 Sep 2024 08:50:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1727081441; bh=XbiJTxstb2TKquC/befwcMAMjPw/EN8TCmrYDdvf5fQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=cD1t5cr6MuHSh35ccGjV9ZCD8kLd1mFCKrON89IMnItxepo9H3rV7cTu7uxKYbm/6 thp2pHhV8n1ZSD3N7cpeVQFFx3cEj82lXDaQpX0Ajfqkd0lYNeF8AlYQ6UV+VNMk95 5Rsb4M3Id15d3flDnqIJDm+qAwR3xnVFq1jtsXKL165Q3oad9pogTKEEaUOEKr3iGs NLrvv7zSAeYlS6vr2WoEOz6UtvEkXKFdDEGhwC7QgeyBucrVwNpsBt1XIwmFwp8gTO wwKmNHPQzZIJSEVmmbSDefR4tH83ulSxtLciVtDj2Ja+DrXbDKsgtMnl48+Gz6ps5a PggYQloroHVXQ== Date: Mon, 23 Sep 2024 04:50:40 -0400 From: Sasha Levin To: Greg Thelen Cc: Chen Ridong , Tejun Heo , Shivani Agarwal , Greg Kroah-Hartman , stable@vger.kernel.org Subject: Re: 5.10.225 stable kernel cgroup_mutex not held assertion failure Message-ID: References: Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: On Wed, Sep 18, 2024 at 11:01:30PM -0700, Greg Thelen wrote: >Linux stable v5.10.226 suffers a lockdep warning when accessing >/proc/PID/cpuset. cset_cgroup_from_root() is called without cgroup_mutex >is held, which causes assertion failure. > >Bisect blames 5.10.225 commit 688325078a8b ("cgroup/cpuset: Prevent UAF >in proc_cpuset_show()"). I've have not easily reproduced the problem >that this change fixes, so I'm not sure if it's best to revert the fix >or adapt it to meet the 5.10 locking expectations. > >The lockdep complaint: > >$ cat /proc/1/cpuset >$ dmesg >[ 198.744891] ------------[ cut here ]------------ >[ 198.744918] WARNING: CPU: 4 PID: 9301 at >kernel/cgroup/cgroup.c:1395 cset_cgroup_from_root+0xb2/0xd0 >[ 198.744957] RIP: 0010:cset_cgroup_from_root+0xb2/0xd0 >[ 198.744960] Code: 02 00 00 74 11 48 8b 09 48 39 cb 75 eb eb 19 49 >83 c6 10 4c 89 f0 48 85 c0 74 0d 5b 41 5e c3 48 8b 43 60 48 85 c0 75 >f3 0f 0b <0f> 0b 83 3d 69 01 ee 01 00 0f 85 78 ff ff ff eb 8b 0f 0b eb >87 66 >[ 198.744962] RSP: 0018:ffffb492608a7ce8 EFLAGS: 00010046 >[ 198.744977] RAX: 0000000000000000 RBX: ffffffff8f4171b8 RCX: >cc949de848c33e00 >[ 198.744979] RDX: 0000000000001000 RSI: ffffffff8f415450 RDI: >ffff92e5417c4dc0 >[ 198.744981] RBP: ffff9303467e3f00 R08: 0000000000000008 R09: >ffffffff9122d568 >[ 198.744983] R10: ffff92e5417c4380 R11: 0000000000000000 R12: >ffff92e3d9506000 >[ 198.744984] R13: 0000000000000000 R14: ffff92e443a96000 R15: >ffff92e3d9506000 >[ 198.744987] FS: 00007f15d94ed740(0000) GS:ffff9302bf500000(0000) >knlGS:0000000000000000 >[ 198.744988] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >[ 198.744990] CR2: 00007f15d94ca000 CR3: 00000002816ca003 CR4: >00000000001706e0 >[ 198.744992] Call Trace: >[ 198.744996] ? __warn+0xcd/0x1c0 >[ 198.745000] ? cset_cgroup_from_root+0xb2/0xd0 >[ 198.745008] ? report_bug+0x87/0xf0 >[ 198.745015] ? handle_bug+0x42/0x80 >[ 198.745017] ? exc_invalid_op+0x16/0x70 >[ 198.745021] ? asm_exc_invalid_op+0x12/0x20 >[ 198.745030] ? cset_cgroup_from_root+0xb2/0xd0 >[ 198.745034] ? cset_cgroup_from_root+0x28/0xd0 >[ 198.745038] cgroup_path_ns_locked+0x23/0x50 >[ 198.745044] proc_cpuset_show+0x115/0x210 >[ 198.745049] proc_single_show+0x4a/0xa0 >[ 198.745056] seq_read_iter+0x14d/0x400 >[ 198.745063] seq_read+0x103/0x130 >[ 198.745074] vfs_read+0xea/0x320 >[ 198.745078] ? do_user_addr_fault+0x25b/0x390 >[ 198.745085] ? do_user_addr_fault+0x25b/0x390 >[ 198.745090] ksys_read+0x70/0xe0 >[ 198.745096] do_syscall_64+0x2d/0x40 >[ 198.745099] entry_SYSCALL_64_after_hwframe+0x61/0xcb I'll queue up d23b5c577715 ("cgroup: Make operations on the cgroup root_list RCU safe") onto 5.15/5.10. Thanks for reporting! -- Thanks, Sasha