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Mon, 9 Feb 2026 17:42:45 +0000 (GMT) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 Date: Mon, 09 Feb 2026 18:42:40 +0100 Message-Id: From: "Christoph Schlameuss" Cc: , , , , , , , , , , , , , , To: "Claudio Imbrenda" , Subject: Re: [PATCH v1 3/3] KVM: s390: vsie: Fix race in acquire_gmap_shadow() X-Mailer: aerc 0.21.0 References: <20260206143553.14730-1-imbrenda@linux.ibm.com> <20260206143553.14730-4-imbrenda@linux.ibm.com> In-Reply-To: <20260206143553.14730-4-imbrenda@linux.ibm.com> X-TM-AS-GCONF: 00 X-Authority-Analysis: v=2.4 cv=KZnfcAYD c=1 sm=1 tr=0 ts=698a1c9b cx=c_pps a=bLidbwmWQ0KltjZqbj+ezA==:117 a=bLidbwmWQ0KltjZqbj+ezA==:17 a=IkcTkHD0fZMA:10 a=HzLeVaNsDn8A:10 a=VkNPw1HP01LnGYTKEx00:22 a=Mpw57Om8IfrbqaoTuvik:22 a=GgsMoib0sEa3-_RKJdDe:22 a=VnNF1IyMAAAA:8 a=XBZ43gOJIXd42L75nJwA:9 a=QEXdDO2ut3YA:10 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwMjA5MDE0NSBTYWx0ZWRfX0KGuyhabyvkx 2i5TIUIwyiSLieiy70DJxfdx6DSfxEqMoaQ/clG1CSkSlql1l/CGLMhefg6GDD1eC2eP6ri6Kfb 450ndgBT1kX6Qg0JGOt1uZGe5msFgy/c8HWoWKacV+c4qRcg65fO9SPZM7hbQ6SG8TSKEspOUbB y8kpt34IaYqasiRvFJ6lU2qdHR21rG89wD488nFPGh215z+reX/+L5/Jo0HprIVoOvkvgQ50ig6 /YQyt+4pHUGCDb969ly9ZQmhrfV0BX/59VRSx4MwggHMO6t0H61OkJp1brAv1LhwydtgGs3Lujn 5mygFKkgQZMMbFesHyk0WXl7dWh9gujOtlnVRrp70z8u37brIDzP6buu8qfKnzPDA8WTNTrooRt lWBsXozztnSX7wnoqH9VJCda9zFbiIYz1xc6FvAId4IvJ5KzpAaXiKDXMa68gs+B6JuHowmsvQK 1Z9HEziQZvplg9cL7dA== X-Proofpoint-ORIG-GUID: NksxR-cadwXkKTxqUI262NmHaQ2oiJEU X-Proofpoint-GUID: NksxR-cadwXkKTxqUI262NmHaQ2oiJEU X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.51,FMLib:17.12.100.49 definitions=2026-02-09_01,2026-02-09_03,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 impostorscore=0 bulkscore=0 priorityscore=1501 adultscore=0 clxscore=1015 suspectscore=0 phishscore=0 malwarescore=0 lowpriorityscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2601150000 definitions=main-2602090145 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 Reviewed-by: Christoph Schlameuss > --- > arch/s390/kvm/gmap.c | 15 ++++++++++++--- > arch/s390/kvm/vsie.c | 6 +++++- > 2 files changed, 17 insertions(+), 4 deletions(-)