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 DD85F282F00 for ; Sat, 11 Apr 2026 19:23:21 +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=1775935401; cv=none; b=IUquGMngArS1BVXjqSiWAZF1E3l5p+3+hrpwOgBj+l+8AK7eWbh1mMc09aY4UYCKj+nXGiRQGQcopQRvadOPe/YUEc+IW/i+cZnFkOzL1gUM6jMex4LbeRU6D830F3yj+FHDblEKzaGRd8llNgwpbe/bZDqbVEgI0A5hzOohnBY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775935401; c=relaxed/simple; bh=qya5uqpvgIUd7+QRZN3R1QXtOBc6L9zzRRlirnmUS9k=; h=Date:From:To:Cc:Message-ID:In-Reply-To:References:Subject: Mime-Version:Content-Type; b=h1iaSBLQ7lY/qoPobHZ1LZhgg1QwOsQ6+3FzdaVzEkI1dBcmAEMs82eFffnk9xJ+yt5mxdVO8zT97ZK5YRpU3LJ0eco9sM3vQjgpf8ZTxWqyirtjBkyvz1e1Y46SuYjteBb3MSeXhvHacoTv7zCmF/TzcpweoToADke+MddGfnk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=PtLSEtXJ; 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="PtLSEtXJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 58B6EC4AF09; Sat, 11 Apr 2026 19:23:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1775935401; bh=qya5uqpvgIUd7+QRZN3R1QXtOBc6L9zzRRlirnmUS9k=; h=Date:From:To:Cc:In-Reply-To:References:Subject:From; b=PtLSEtXJ/ld5QXsFcbdy6DJFkw66bZHmHuUoeuowTcuXrAbriutuOm/muOKNO8oLR tcn3Us9jZhQoK75Xgqb7k3TlIXiG0YdrzJEv4RyRjeqJBHmW6kHz2fnBuEcETFAcoY G/q30qZTA6LhP0SJQiw0LDPmbP8B4PILTO6gVlhSUSd02IIBNbRHJJYSMcc3C9smx5 F9kFr2Jjesdadhk6QaQSV9PGQdxOdG/yXAKYJJ/5JJNkJIQSaI2GPh0USH4fkyY3OV JTXNh8vIFwRt30eYZ4vCCllUzB+gb+Ed/fRM6aAYUqe1/EJ9ftceRjO4A7C+xJKUUB fppu+jQ7luEAA== Received: from phl-compute-02.internal (phl-compute-02.internal [10.202.2.42]) by mailfauth.phl.internal (Postfix) with ESMTP id 5636AF4006F; Sat, 11 Apr 2026 15:23:20 -0400 (EDT) Received: from phl-frontend-04 ([10.202.2.163]) by phl-compute-02.internal (MEProxy); Sat, 11 Apr 2026 15:23:20 -0400 X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeefhedrtddtgdeffedvtdcutefuodetggdotefrod ftvfcurfhrohhfihhlvgemucfhrghsthforghilhdpuffrtefokffrpgfnqfghnecuuegr ihhlohhuthemuceftddtnecusecvtfgvtghiphhivghnthhsucdlqddutddtmdenucfjug hrpeffhffvvefkjghfufggtgfgsehtqhertddttdejnecuhfhrohhmpeffrghnucghihhl lhhirghmshcuoegujhgsfieskhgvrhhnvghlrdhorhhgqeenucggtffrrghtthgvrhhnpe dukeelueetjeekgeeiheelvdehleekgeejvdejvdetgfdugffgveefgfejhffhvdenucff ohhmrghinhepkhgvrhhnvghlrdhorhhgnecuvehluhhsthgvrhfuihiivgeptdenucfrrg hrrghmpehmrghilhhfrhhomhepughjsgifodhmvghsmhhtphgruhhthhhpvghrshhonhgr lhhithihqddujeejvdeftdegheehqdeffeefleegtdegjedqughjsgifpeepkhgvrhhnvg hlrdhorhhgsehfrghsthhmrghilhdrtghomhdpnhgspghrtghpthhtohepudefpdhmohgu vgepshhmthhpohhuthdprhgtphhtthhopegurghvvgdrjhhirghnghesihhnthgvlhdrtg homhdprhgtphhtthhopegurhhivhgvrhdqtghorhgvsehlihhsthhsrdhlihhnuhigrdgu vghvpdhrtghpthhtoheplhhinhhugidqkhgvrhhnvghlsehvghgvrhdrkhgvrhhnvghlrd horhhgpdhrtghpthhtoheplhhinhhugidqtgiglhesvhhgvghrrdhkvghrnhgvlhdrohhr ghdprhgtphhtthhopehgrhgvghhkhheslhhinhhugihfohhunhgurghtihhonhdrohhrgh dprhgtphhtthhopehrrghfrggvlheskhgvrhhnvghlrdhorhhgpdhrtghpthhtohepihhr rgdrfigvihhnhiesihhnthgvlhdrtghomhdprhgtphhtthhopegshhgvlhhgrggrshesgh hoohhglhgvrdgtohhmpdhrtghpthhtohepuggrkhhrsehkvghrnhgvlhdrohhrgh X-ME-Proxy: Feedback-ID: i67ae4b3e:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Sat, 11 Apr 2026 15:23:19 -0400 (EDT) Date: Sat, 11 Apr 2026 12:23:18 -0700 From: Dan Williams To: Dave Jiang Cc: driver-core@lists.linux.dev, linux-kernel@vger.kernel.org, linux-cxl@vger.kernel.org, Greg Kroah-Hartman , "Rafael J. Wysocki" , Ira Weiny , Bjorn Helgaas , Danilo Krummrich , Davidlohr Bueso , Jonathan Cameron , Vishal Verma , Ben Cheatham Message-ID: <69da9fa696d0f_6c31a100e8@djbw-dev.notmuch> In-Reply-To: References: <20260314-fix_access_endpoint_without_drv_check-v2-0-4c09edf2e1db@zohomail.com> <20260314-fix_access_endpoint_without_drv_check-v2-2-4c09edf2e1db@zohomail.com> Subject: Re: [PATCH v2 2/4] cxl/memdev: Hold memdev lock during memdev poison injection/clear Precedence: bulk X-Mailing-List: linux-cxl@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Dave Jiang wrote: > = > = > On 3/18/26 4:59 AM, Li Ming wrote: > > = > > =E5=9C=A8 2026/3/17 23:00, Dave Jiang =E5=86=99=E9=81=93: > >> > >> On 3/14/26 12:06 AM, Li Ming wrote: > >>> CXL memdev poison injection/clearing debugfs interfaces are visible= > >>> before the CXL memdev endpoint initialization, If user accesses the= > >>> interfaces before cxlmd->endpoint updated, it is possible to access= an > >>> invalid endpoint in cxl_dpa_to_region(). > >>> > >>> Hold CXL memdev lock at the beginning of the interfaces, this block= s the > >>> interfaces until CXL memdev probing completed. > >>> > >>> The following patch will check the given endpoint validity in > >>> cxl_dpa_to_region(). > >>> > >>> Suggested-by: Dan Williams > >>> Reviewed-by: Dave Jiang > >>> Reviewed-by: Alison Schofield > >>> Signed-off-by: Li Ming > >> Hi Ming, I dropped this patch with Dan's comments [1] and updated cx= l/next. Please check and make sure everything looks ok to you. Thanks! > >> > >> [1]: https://lore.kernel.org/linux-cxl/69b8b81621e16_452b100e@dwilli= a2-mobl4.notmuch/ > > = > > Hi Dave, > > = > > I think there is no change needed in this patch, just need a independ= ent patch for holding memdev lock in cxl_region_debugfs_poison_inject/cle= ar. > > = > > Or you want to review this patch again? > = > No. Maybe I misunderstood the comment from Dan. So we should keep this = patch? tl;dr: yes, this patch is *now* valid. As originally structured having patch2 before patch3 added no value. Going forward I would say do not structure a series such that a new lock taken in patch N starts being useful in patch N+1. I assume that is what: "The following patch will check the given endpoint validity in cxl_dpa_to_region()." ...is trying to say, but when commits are applied to the tree it is difficult to see that this commit was from a series. So do pick this one up, but the changelog needs adjusting. Something like: "cxl_dpa_to_region() assumes that it is running a context where it is not= racing changes to "cxlmd->dev.driver". Acquire the memdev device lock in the debugfs entry points to preclude debugfs usage racing cxl_mem driver detach." With that you can add: Reviewed-by: Dan Williams =