linux-kernel - Re: [PATCH] s390/cio: fix device lifecycle handling in css_alloc

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <20260204115952.6906A12-hca@linux.ibm.com>
Date: Wed, 4 Feb 2026 12:59:52 +0100
From: Heiko Carstens <hca@...ux.ibm.com>
To: Salah Triki <salah.triki@...il.com>
Cc: Vineeth Vijayan <vneethv@...ux.ibm.com>,
        Peter Oberparleiter <oberpar@...ux.ibm.com>,
        Vasily Gorbik <gor@...ux.ibm.com>,
        Alexander Gordeev <agordeev@...ux.ibm.com>,
        Christian Borntraeger <borntraeger@...ux.ibm.com>,
        Sven Schnelle <svens@...ux.ibm.com>, linux-s390@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] s390/cio: fix device lifecycle handling in
 css_alloc_subchannel()

On Fri, Jan 30, 2026 at 09:47:59PM +0100, Salah Triki wrote:
> `css_alloc_subchannel()` calls `device_initialize()` before setting up
> the DMA masks. If `dma_set_coherent_mask()` or `dma_set_mask()` fails,
> the error path frees the subchannel structure directly, bypassing
> the device model reference counting.
> 
> Once `device_initialize()` has been called, the embedded struct device
> must be released via `put_device()`, allowing the release callback to
> free the container structure.
> 
> Fix the error path by dropping the initial device reference with
> `put_device()` instead of calling `kfree()` directly.
> 
> This ensures correct device lifetime handling and avoids potential
> use-after-free or double-free issues.
> 
> Fixes: e5dcf0025d7af ("s390/css: move subchannel lock allocation")
> 
> Signed-off-by: Salah Triki <salah.triki@...il.com>
> ---
>  drivers/s390/cio/css.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Applied, thanks.