linux-kernel - Re: [PATCH v1 3/3] KVM: s390: vsie: Fix race in acquire_gmap

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 for Android: free password hash cracker in your pocket

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

Message-Id: <DGAM7SZPZQU4.3UM38Z6R1DB7Q@linux.ibm.com>
Date: Mon, 09 Feb 2026 18:42:40 +0100
From: "Christoph Schlameuss" <schlameuss@...ux.ibm.com>
To: "Claudio Imbrenda" <imbrenda@...ux.ibm.com>, <kvm@...r.kernel.org>
Cc: <linux-kernel@...r.kernel.org>, <linux-s390@...r.kernel.org>,
        <borntraeger@...ibm.com>, <frankja@...ux.ibm.com>, <nsg@...ux.ibm.com>,
        <nrb@...ux.ibm.com>, <seiden@...ux.ibm.com>, <gra@...ux.ibm.com>,
        <schlameuss@...ux.ibm.com>, <hca@...ux.ibm.com>, <svens@...ux.ibm.com>,
        <agordeev@...ux.ibm.com>, <gor@...ux.ibm.com>, <david@...nel.org>,
        <gerald.schaefer@...ux.ibm.com>
Subject: Re: [PATCH v1 3/3] KVM: s390: vsie: Fix race in
 acquire_gmap_shadow()

On Fri Feb 6, 2026 at 3:35 PM CET, Claudio Imbrenda wrote:
> The shadow gmap returned by gmap_create_shadow() could get dropped
> before taking the gmap->children_lock. This meant that the shadow gmap
> was sometimes being used while its reference count was 0.
>
> Fix this by taking the additional reference inside gmap_create_shadow()
> while still holding gmap->children_lock, instead of afterwards.
>
> Fixes: e38c884df921 ("KVM: s390: Switch to new gmap")
> Signed-off-by: Claudio Imbrenda <imbrenda@...ux.ibm.com>

Reviewed-by: Christoph Schlameuss <schlameuss@...ux.ibm.com>

> ---
>  arch/s390/kvm/gmap.c | 15 ++++++++++++---
>  arch/s390/kvm/vsie.c |  6 +++++-
>  2 files changed, 17 insertions(+), 4 deletions(-)