From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.15]) (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 A485153E24; Tue, 18 Jun 2024 20:40:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.15 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718743244; cv=none; b=J1+SF7+XoMpkAmYrtAUO6b0rMWgtQnxitjFS6vyVaQ/tev87TqGu4fXZj5Pqi2PI+/Qld5hgU+HyJIiiLW9YuXOTcT/UPFV7Q8Dn2hFnQmoTn4PYDupOMAqpGOfEoTThUN4Fgv/sKq8aIStZJviZCGTiIxzRQ/CvAHBgsmDxm7g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718743244; c=relaxed/simple; bh=SkekENq0hipzevfj00AK20IlSkJZ1QWx0rBZmBBmZAk=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=Hj/KMWjm2otkI0lOjd9rtELaG6TyNGqWOw1N7470ysEDbDOzs5fStI6keZDMGaGejmZb50xjLC9Ql4df9/STTv6lEGLCC5I6TnnpJErlhcP4Piz1FCMau4HQxrlveltzdDGT0Jevp3WXqVn3WlCROnyNjUcSmK+eg66xcDbVUaM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=none smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=RYfcb9bM; arc=none smtp.client-ip=192.198.163.15 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="RYfcb9bM" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1718743243; x=1750279243; h=message-id:subject:from:to:cc:date:in-reply-to: references:content-transfer-encoding:mime-version; bh=SkekENq0hipzevfj00AK20IlSkJZ1QWx0rBZmBBmZAk=; b=RYfcb9bMot4oreqhTeXvl+7p9PScBlwLZXr4h+5+0VKJ50Tn7Km7cK+M cnZQPqrfGlqxcE3TQBC4SvXuETuH2wy/wJscj69Op/qoUVXzjh+SAqcqO xQO9XHTxZ5A+IDDoTJgxMzZQCRXeFSDlxLfHEvrHG4rb9M1BZC4+QmICM n0lbBJ2lz0eXxXAGRzei5SfJ8h94nHoKfQLQf+icD7BBoymVdFL2fwFbX TBtD9uceqZM/Mt8shsu6mNUslaS3oEmwBVWlazGadf03S06v4OLcy2sap sKJQ6ZSutFhYgqoO1RRVxbLkX9Yw7wlRcOveGeYepH9oxTRIvutkwl9Vp Q==; X-CSE-ConnectionGUID: vByXXz5HRKiHDLvYjT8SnA== X-CSE-MsgGUID: HbGa1iZXToO+9eWv4PyRPw== X-IronPort-AV: E=McAfee;i="6700,10204,11107"; a="15798674" X-IronPort-AV: E=Sophos;i="6.08,247,1712646000"; d="scan'208";a="15798674" Received: from fmviesa007.fm.intel.com ([10.60.135.147]) by fmvoesa109.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Jun 2024 13:40:41 -0700 X-CSE-ConnectionGUID: WFCrUdItQcS/sWSjctIuPA== X-CSE-MsgGUID: j0j7mdG0R12yVzQFC8VNfg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.08,247,1712646000"; d="scan'208";a="41521742" Received: from apahleva-mobl.amr.corp.intel.com (HELO [10.209.7.169]) ([10.209.7.169]) by fmviesa007-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Jun 2024 13:40:41 -0700 Message-ID: <1c33b2c904f6055400817053504198e3bf3fad3d.camel@linux.intel.com> Subject: Re: [PATCH 3/3] fs/file.c: move sanity_check from alloc_fd() to put_unused_fd() From: Tim Chen To: Michal Hocko Cc: Mateusz Guzik , Yu Ma , viro@zeniv.linux.org.uk, brauner@kernel.org, jack@suse.cz, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, tim.c.chen@intel.com, pan.deng@intel.com, tianyou.li@intel.com Date: Tue, 18 Jun 2024 13:40:40 -0700 In-Reply-To: References: <20240614163416.728752-1-yu.ma@intel.com> <20240614163416.728752-4-yu.ma@intel.com> <8fa3f49b50515f8490acfe5b52aaf3aba0a36606.camel@linux.intel.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.44.4 (3.44.4-3.fc36) Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Tue, 2024-06-18 at 10:35 +0200, Michal Hocko wrote: > On Mon 17-06-24 11:04:41, Tim Chen wrote: > > diff --git a/kernel/sys.c b/kernel/sys.c > > index 3a2df1bd9f64..b4e523728c3e 100644 > > --- a/kernel/sys.c > > +++ b/kernel/sys.c > > @@ -1471,6 +1471,7 @@ static int do_prlimit(struct task_struct *tsk, un= signed int resource, > > return -EINVAL; > > resource =3D array_index_nospec(resource, RLIM_NLIMITS); > > =20 > > + task_lock(tsk->group_leader); > > if (new_rlim) { > > if (new_rlim->rlim_cur > new_rlim->rlim_max) > > return -EINVAL; >=20 > This is clearly broken as it leaves the lock behind on the error, no? Thanks for pointing that out. Need unlock before return. I don't like adding task_lock in alloc_fd path if there are multiple alloc_fd going on causing contention. =C2=A0 The race with rlimit change should be a very rare thing. Should be sufficient that patch one check for fd not going beyond the observed rlimit. Tim