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Wed, 16 Sep 2026 23:09:45 +0000 (GMT) Received: from li-4c4c4544-0054-3910-8039-c3c04f423534.ibm.com.com (unknown [9.61.141.190]) by smtpav06.wdc07v.mail.ibm.com (Postfix) with ESMTP; Wed, 16 Sep 2026 23:09:45 +0000 (GMT) From: Tyrel Datwyler To: james.bottomley@hansenpartnership.com, martin.petersen@oracle.com Cc: linux-scsi@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, brking@linux.ibm.com, davemarq@linux.ibm.com, Tyrel Datwyler Subject: [PATCH 17/20] scsi: ibmvfc: fix TOCTOU race in ibmvfc_nvme_create_queue() on adapter removal Date: Wed, 16 Sep 2026 16:09:18 -0700 Message-ID: <20260916230921.2204729-18-tyreld@linux.ibm.com> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260916230921.2204729-1-tyreld@linux.ibm.com> References: <20260916230921.2204729-1-tyreld@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwOTE2MDMyMiBTYWx0ZWRfX3hFBk2sWSeGK 6CcBUhpGNRnfiehjvKNcJAr7EmGdUpIrTmM+uizG5tyixvSOCV0eX1wQdJPyCUasp9gxTt9Rb2u XWje7ToZk56vNQShBLNUdkiqFvOOXpooZjlKiK9BmbwrDofNDK3NC+VvnXXqOM8DNdx19RtHLgg vVacvf+bYvCred0RQ/+TFfUF6fW359A0cmuwZvNGOk0tePgJCY4wuhl6ckmtXThtlMP+WEcrPSx vVraimgRd9pTiDd89E1tKoQMVVeWvSG1wKWG3lr2i1VUUJizCIX29XmDTevM3aAj6VZk3MWAWBk ELWD9fup+QxgDLKg5tb30M7o/+PoTnDUEb5uby7+M976NSZvLer+kXuZg3Zzb9BbAdFN2zv/8rI MUKyumFYvU6ZwvQwiWODXKG5tjB18uh9zN8yw276ay9dBI6JUWUfK+UPEX9/HOckWev/Ue7IO5t eNRgm8Wpkwp0OHkPRwQ== X-Authority-Analysis: v=2.4 cv=E/NYNqdl c=1 sm=1 tr=0 ts=6aab21bc cx=c_pps a=AfN7/Ok6k8XGzOShvHwTGQ==:117 a=AfN7/Ok6k8XGzOShvHwTGQ==:17 a=VdqzKS8jKosA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=V8glGbnc2Ofi9Qvn3v5h:22 a=VnNF1IyMAAAA:8 a=M1I_nbD3KY5Z_so_vh8A:9 X-Proofpoint-ORIG-GUID: OeaXTyYp18V3aEvk-4z3Q1c3hLJLohuE X-Proofpoint-Spam-Info: AW1haW4tMjYwOTE2MDMyMiBTYWx0ZWRfX6J0s20Buri4a Fdw8Kd7iLLXi1qR9s1aS0Mqg9agGVWN2FvAZXskfRpOuMuAVk9Ue4zO1eE8oaGHGxBvstJW8G0M voTKFgeRduZ9iS5SEj9CGEwzTzznckU= X-Proofpoint-GUID: OeaXTyYp18V3aEvk-4z3Q1c3hLJLohuE X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-09-16_03,2026-09-16_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 impostorscore=0 lowpriorityscore=0 priorityscore=1501 spamscore=0 adultscore=0 clxscore=1015 bulkscore=0 malwarescore=0 suspectscore=0 phishscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2609040000 definitions=main-2609160322 ibmvfc_remove() called ibmvfc_release_sub_crqs() before ibmvfc_nvme_unregister(). ibmvfc_release_sub_crqs() frees the nvme_scrqs.scrqs array and sets active_queues to 0, but the nvme-fc transport is still live at that point and can call back into ibmvfc_nvme_create_queue(). That callback reads active_queues and dereferences scrqs without any lock, so the window between the guard check and the actual use can race with the teardown, leading to: - divide-by-zero in '(qidx - 1) % vhost->nvme_scrqs.active_queues' when active_queues has been zeroed concurrently, and - NULL pointer dereference on 'vhost->nvme_scrqs.scrqs[qhandle->index]' when scrqs has been freed and set to NULL concurrently. ibmvfc_nvme_unregister() already calls nvme_fc_unregister_localport() followed by wait_for_completion(), which blocks until the transport has fully quiesced all queue operations. It just needs to happen before the sub-CRQ memory is released. Move ibmvfc_nvme_unregister() before ibmvfc_release_sub_crqs() in ibmvfc_remove() so the transport is quiesced before the sub-CRQ arrays are freed. The reset path (ibmvfc_reset_crq) is unaffected: it only deregisters sub-CRQs at the hypervisor level and never frees them, so active_queues and scrqs remain valid across a reset. Fixes: 186f72e38029 ("scsi: ibmvfc: implement LLDD callbacks for mapping nvme-fc queues") Signed-off-by: Tyrel Datwyler --- drivers/scsi/ibmvscsi/ibmvfc-core.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/drivers/scsi/ibmvscsi/ibmvfc-core.c b/drivers/scsi/ibmvscsi/ibmvfc-core.c index 7af1867b69c5..93189692191e 100644 --- a/drivers/scsi/ibmvscsi/ibmvfc-core.c +++ b/drivers/scsi/ibmvscsi/ibmvfc-core.c @@ -6992,11 +6992,10 @@ static void ibmvfc_remove(struct vio_dev *vdev) list_splice_init(&vhost->purge, &purge); spin_unlock_irqrestore(&vhost->host->host_lock, flags); ibmvfc_complete_purge(&purge); + ibmvfc_nvme_unregister(vhost); ibmvfc_release_sub_crqs(vhost); ibmvfc_release_crq_queue(vhost); - ibmvfc_nvme_unregister(vhost); - ibmvfc_free_mem(vhost); spin_lock(&ibmvfc_driver_lock); list_del(&vhost->queue); -- 2.55.0