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Wed, 4 Mar 2026 18:14:08 +0000 (GMT) Message-ID: Date: Wed, 4 Mar 2026 13:14:07 -0500 Precedence: bulk X-Mailing-List: linux-scsi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/1] scsi: virtio_scsi: move INIT_WORK calls to virtscsi_init To: Eric Farman , linux-scsi@vger.kernel.org Cc: linux-kernel@vger.kernel.org, virtualization@lists.linux.dev, mst@redhat.com, jasowang@redhat.com, pbonzini@redhat.com, stefanha@redhat.com, eperezma@redhat.com, James.Bottomley@HansenPartnership.com, martin.petersen@oracle.com, mjrosato@linux.ibm.com, frankja@linux.ibm.com References: <20260226204345.1904786-1-jdaley@linux.ibm.com> <20260226204345.1904786-2-jdaley@linux.ibm.com> <77b2b44d7101d55151c8e9852ce41783205ed987.camel@linux.ibm.com> Content-Language: en-US From: Joshua Daley In-Reply-To: <77b2b44d7101d55151c8e9852ce41783205ed987.camel@linux.ibm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwMzA0MDE0OCBTYWx0ZWRfX4KpazI42zp4Q nvCMLCxG0s7tGjhqmxqKZ4gtV/Z+LkqAJ/BUd0A1hVoPrmVbdIQAyPVbw7mJ7q4oCuB6V8c59Qf z4P2t99M0hKhjCric1CW73OS8lRkXs0HC14SKdjaMag/UN5bV7QXdRq33I93ezcG468W12GygV4 W+cD2l6omwRv2yGN8rCCipiJVUZ3ZL2fynBin50NrJSgXYnNtXbMeb6d7SUKu9gf4MXU1rf5nHN FcER47W/r8JNh56WKeV50sg+Wi1loQrN6xWCwrZMSUiGm/glmGIozhGnc764mFsKlMqQwqnUXAl aayr3HnWCi1Qe/NqQe9B5FNThIkiHNOgbE/d0O4VgNp3+Qa3OPB8S+RAxQ1VXah4/XACZ0IjhH7 zyqGJrgz8yXPofv2n6DuyfkDL6sX/NroRaFT/t9/xait9hM+8O4XVdYQcrQ5AfpRb9NeDOrxksN TU5Hog3h1LAIBSk+0ig== X-Proofpoint-ORIG-GUID: UWWdT2tYBCkJBGFJiu7PLn4JWP3ZAbku X-Proofpoint-GUID: UWWdT2tYBCkJBGFJiu7PLn4JWP3ZAbku X-Authority-Analysis: v=2.4 cv=AobjHe9P c=1 sm=1 tr=0 ts=69a87673 cx=c_pps a=3Bg1Hr4SwmMryq2xdFQyZA==:117 a=3Bg1Hr4SwmMryq2xdFQyZA==:17 a=IkcTkHD0fZMA:10 a=Yq5XynenixoA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=RzCfie-kr_QcCd8fBx8p:22 a=VnNF1IyMAAAA:8 a=eS4R6lfaZEnlwP-vdxAA:9 a=QEXdDO2ut3YA:10 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.51,FMLib:17.12.100.49 definitions=2026-03-04_07,2026-03-04_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 phishscore=0 lowpriorityscore=0 bulkscore=0 impostorscore=0 malwarescore=0 spamscore=0 clxscore=1015 suspectscore=0 adultscore=0 priorityscore=1501 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2602130000 definitions=main-2603040148 On 3/3/2026 4:45 PM, Eric Farman wrote: > On Thu, 2026-02-26 at 21:43 +0100, Joshua Daley wrote: >> The last step of virtscsi_handle_event is to call virtscsi_kick_event, >> which calls INIT_WORK on it's own work item. INIT_WORK resets the >> work item's data bits to 0. >> >> If this occurs while the work item is being flushed by >> cancel_work_sync, then kernel/workqueue.c/work_offqd_enable triggers a >> kernel warning, as it expects the "disable" bit to be 1: >> >> [ 21.450115] workqueue: work disable count underflowed >> [ 21.450117] WARNING: CPU: 1 PID: 56 at kernel/workqueue.c:4328 enable_work+0x10a/0x120 >> ... >> [ 21.450171] Call Trace: >> [ 21.450173] [<000003db2e5bdc3e>] enable_work+0x10e/0x120 >> [ 21.450176] ([<000003db2e5bdc3a>] enable_work+0x10a/0x120) >> [ 21.450178] [<000003db2e5bdd86>] cancel_work_sync+0x86/0xa0 >> [ 21.450181] [<000003daae97d9e4>] virtscsi_remove+0xb4/0xd0 [virtio_scsi] >> [ 21.450184] [<000003db2ef3b5ca>] virtio_dev_remove+0x6a/0xd0 >> [ 21.450186] [<000003db2ef9106c>] device_release_driver_internal+0x1ac/0x260 >> [ 21.450190] [<000003db2ef8edc8>] bus_remove_device+0xf8/0x190 >> [ 21.450192] [<000003db2ef88d72>] device_del+0x142/0x340 >> [ 21.450194] [<000003db2ef88fa0>] device_unregister+0x30/0xa0 >> [ 21.450196] [<000003db2ef3b2fa>] unregister_virtio_device+0x2a/0x40 >> >> This warning may occur if a controller is detached immediately >> following a disk detach. >> >> Move the INIT_WORK call to prevent this. Don't re-init event list >> work items in virtscsi_kick_event, init them only once in >> virtscsi_init instead. >> >> Signed-off-by: Joshua Daley > > The fact that the INIT_WORK points to virtscsi_handle_event(), which itself calls > virtscsi_kick_event() and re-inits the workqueue struct today, does seem odd. Moving this to _init, > as part of the _probe() process, seems correct to me. One nit below, but FWIW: > > Reviewed-by: Eric Farman > Tested-by: Eric Farman > >> --- >> drivers/scsi/virtio_scsi.c | 6 +++++- >> 1 file changed, 5 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c >> index 0ed8558dad72..173092931df6 100644 >> --- a/drivers/scsi/virtio_scsi.c >> +++ b/drivers/scsi/virtio_scsi.c >> @@ -242,7 +242,6 @@ static int virtscsi_kick_event(struct virtio_scsi *vscsi, > > Just before this hunk is a prototype for virtscsi_handle_event(), since it was previously used in > this function but defined afterwards. I suspect it can be removed now? > Yes, looks like it can be removed safely. That should probably be done in a separate patch. >> struct scatterlist sg; >> unsigned long flags; >> >> - INIT_WORK(&event_node->work, virtscsi_handle_event); >> sg_init_one(&sg, event_node->event, sizeof(struct virtio_scsi_event)); >> >> spin_lock_irqsave(&vscsi->event_vq.vq_lock, flags); >> @@ -898,6 +897,11 @@ static int virtscsi_init(struct virtio_device *vdev, >> virtscsi_config_set(vdev, cdb_size, VIRTIO_SCSI_CDB_SIZE); >> virtscsi_config_set(vdev, sense_size, VIRTIO_SCSI_SENSE_SIZE); >> >> + if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG)) { >> + for (i = 0; i < VIRTIO_SCSI_EVENT_LEN; i++) >> + INIT_WORK(&vscsi->event_list[i].work, virtscsi_handle_event); >> + } >> + >> err = 0; >> >> out: