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[103.229.16.4]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-7a22ff34b8bsm11057337b3a.22.2025.10.21.04.08.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 21 Oct 2025 04:08:12 -0700 (PDT) From: Cong Zhang Date: Tue, 21 Oct 2025 19:07:56 +0800 Subject: [PATCH] virtio_blk: NULL out vqs to avoid double free on failed resume Precedence: bulk X-Mailing-List: linux-kernel@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 Message-Id: <20251021-virtio_double_free-v1-1-4dd0cfd258f1@oss.qualcomm.com> X-B4-Tracking: v=1; b=H4sIAItp92gC/33NwQqDMAyA4VeRnldJ21XrTnuPMaRqnAW1W6tlQ 3z3VQ87yS6BP5AvC/HoDHpySRbiMBhv7BiDnRJSd3p8IDVNbMKBSyh4RoNxk7FlY+eqx7J1iDT XlVLQKK5ZTuLh02Fr3jt6u8fujJ+s++w/Atu2f7nAKFApMXJnUIWEq/U+fc26r+0wpHGQTQ38J zFg4lDiURKFLgQILTLUB9K6rl8bkiQoBQEAAA== X-Change-ID: 20250926-virtio_double_free-7ab880d82a17 To: "Michael S. Tsirkin" , Jason Wang , Xuan Zhuo , =?utf-8?q?Eugenio_P=C3=A9rez?= , Paolo Bonzini , Stefan Hajnoczi , Jens Axboe Cc: linux-arm-msm@vger.kernel.org, virtualization@lists.linux.dev, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, pavan.kondeti@oss.qualcomm.com, Cong Zhang X-Mailer: b4 0.14.2 X-Developer-Signature: v=1; a=ed25519-sha256; t=1761044889; l=1781; i=cong.zhang@oss.qualcomm.com; s=20250926; h=from:subject:message-id; bh=UVetEv7dc6qihnycViKp+IETEpl1ulKaq7ZGfb1R8FA=; b=+2jE96K3P2nEDXz2nqE32h52ySapgBjuDfpmmaxvxcyWPTxgX5cVa+SqtSFX28dIRkmrmz6yb Jdz/4pJqCx6ADrZYPgriwtXjoi41c4t2eZrsNiJTuuDbB4J+X2dr/fb X-Developer-Key: i=cong.zhang@oss.qualcomm.com; a=ed25519; pk=8SBh3ey5igz2nlW+UFC6khFvaNPgG7MmbWtAeO2s6n8= X-Proofpoint-ORIG-GUID: OMR-Mw7HuPJxqHJfbc5croBpro8Ravz_ X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUxMDE4MDAzMiBTYWx0ZWRfX4MFCOfivin1a ihhIu6CBC6RLN2eRq2sa5kEpN+Ps525YWyQlO6b9WkjN9eP3kUhtyxJfDcOg09ZyKVNSoqBmIBO nG86hfbNMkZ3+sFVF9+9vTt6pYXYqAURhhScwHN1GagHoBm04NA9a8o4KquUo96AGNSoDDf+Xqc EnllHaG5uKw65bfZ7pG1DMhnudPGv6ohb2ntCaLW2RFId4nIXwGjFt/mPDEAo7ydQxEPQmqndaq eFCpfgYt5kAlyY9RRT1UTUqe7y1VN74Cnw7WLGeXrXe3eW4Y003QtgA+YF085V6L7CtwZxM1Oef UFb0O423qh54MJU1vAw+p8o+lXmi4WLj/gt7J9W0lD2Qk8tDE7CZKiJisCkRtIDIxSuVKm84HmO FArktUvMK1SB1Z7YWiEG8ie/emza6Q== X-Authority-Analysis: v=2.4 cv=U8qfzOru c=1 sm=1 tr=0 ts=68f7699e cx=c_pps a=rEQLjTOiSrHUhVqRoksmgQ==:117 a=nuhDOHQX5FNHPW3J6Bj6AA==:17 a=IkcTkHD0fZMA:10 a=x6icFKpwvdMA:10 a=VkNPw1HP01LnGYTKEx00:22 a=EUspDBNiAAAA:8 a=47QlDNkPX5KzPiwYzcgA:9 a=QEXdDO2ut3YA:10 a=2VI0MkxyNR6bbpdq8BZq:22 X-Proofpoint-GUID: OMR-Mw7HuPJxqHJfbc5croBpro8Ravz_ X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.9,FMLib:17.12.80.40 definitions=2025-10-21_01,2025-10-13_01,2025-03-28_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 impostorscore=0 adultscore=0 bulkscore=0 malwarescore=0 priorityscore=1501 spamscore=0 clxscore=1011 lowpriorityscore=0 phishscore=0 suspectscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2510020000 definitions=main-2510180032 The vblk->vqs releases during freeze. If resume fails before vblk->vqs is allocated, later freeze/remove may attempt to free vqs again. Set vblk->vqs to NULL after freeing to avoid double free. Signed-off-by: Cong Zhang Acked-by: Jason Wang --- The patch fixes a double free issue that occurs in virtio_blk during freeze/resume. The issue is caused by: 1. During the first freeze, vblk->vqs is freed but pointer is not set to NULL. 2. Virtio block device fails before vblk->vqs is allocated during resume. 3. During the next freeze, vblk->vqs gets freed again, causing the double free crash. --- drivers/block/virtio_blk.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c index f061420dfb10c40b21765b173fab7046aa447506..746795066d7f56a01c9a9c0344d= 24f9fa06841eb 100644 --- a/drivers/block/virtio_blk.c +++ b/drivers/block/virtio_blk.c @@ -1026,8 +1026,13 @@ static int init_vq(struct virtio_blk *vblk) out: kfree(vqs); kfree(vqs_info); - if (err) + if (err) { kfree(vblk->vqs); + /* + * Set to NULL to prevent freeing vqs again during freezing. + */ + vblk->vqs =3D NULL; + } return err; } =20 @@ -1598,6 +1603,12 @@ static int virtblk_freeze_priv(struct virtio_device = *vdev) =20 vdev->config->del_vqs(vdev); kfree(vblk->vqs); + /* + * Set to NULL to prevent freeing vqs again after a failed vqs + * allocation during resume. Note that kfree() already handles NULL + * pointers safely. + */ + vblk->vqs =3D NULL; =20 return 0; } --- base-commit: 8e2755d7779a95dd61d8997ebce33ff8b1efd3fb change-id: 20250926-virtio_double_free-7ab880d82a17 Best regards, --=20 Cong Zhang