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Mon, 16 Mar 2026 14:37:43 +0000 (GMT) Message-ID: <74fa682c-e07a-46a2-bd4e-c03ca6d906e6@linux.ibm.com> Date: Mon, 16 Mar 2026 10:37:43 -0400 Precedence: bulk X-Mailing-List: virtualization@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 3/3] scsi: virtio_scsi: move INIT_WORK calls to virtscsi_init To: Joshua Daley , 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, farman@linux.ibm.com, frankja@linux.ibm.com References: <20260312174256.1557045-1-jdaley@linux.ibm.com> <20260312174256.1557045-4-jdaley@linux.ibm.com> Content-Language: en-US From: Matthew Rosato In-Reply-To: <20260312174256.1557045-4-jdaley@linux.ibm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: _vyRgtQyB4wCjbifA2n-9YSEpUCpcIE1 X-Authority-Analysis: v=2.4 cv=KajfcAYD c=1 sm=1 tr=0 ts=69b815bb cx=c_pps a=5BHTudwdYE3Te8bg5FgnPg==:117 a=5BHTudwdYE3Te8bg5FgnPg==:17 a=IkcTkHD0fZMA:10 a=Yq5XynenixoA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=U7nrCbtTmkRpXpFmAIza:22 a=VnNF1IyMAAAA:8 a=vZcffsv9676pwnVvzI4A:9 a=QEXdDO2ut3YA:10 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwMzE2MDEwNyBTYWx0ZWRfX29UOQOf/oojO tlE1tHB6oy8idFZMWMAw9bjthh9UYQIo37504V5+ijHMtaSoB+I5nqkTW3HcBRdcatCdkcC1DAA PwCM4nltAZm4cvc/GVe/+e79WoYQK11H9AThL3YPXEpXGU61R5jMqJkllSBn1dGCsHQdazkGY6K 4bP6J5ngVFNcC+HU84a4zp7ARfZ5Kge5qvO+Xr2pQrwB/Z+1nqtSaHpyZheBnkRpfju1ACnKQG9 c89Uc/R75ohklSHBOnfJY1YBzJJCzlw2kA3uewAoSaBCK9LVLxqQTd5nhvLBj9I9NErt8DP8cA0 Nlu8EcyRbXLR3wrT5+wOl0CmdUosV6STekHh8zXOpBLWwGaOFgSe0UaINyRMT+wJglyS4NXJEVG QZVkatbj6H6XRFdWrzfRshfR4wb11uqsYLwh6+vpddI3Y8GxXzrufzSbCsinFH6K8k2QmbT0ygb 1aW90X/6sBAh57Tj9EQ== X-Proofpoint-GUID: _vyRgtQyB4wCjbifA2n-9YSEpUCpcIE1 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=2026-03-16_04,2026-03-16_03,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 suspectscore=0 adultscore=0 spamscore=0 malwarescore=0 clxscore=1015 impostorscore=0 bulkscore=0 lowpriorityscore=0 priorityscore=1501 phishscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2603050001 definitions=main-2603160107 On 3/12/26 1:42 PM, 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 With patch 2 either squashed in OR moved after this one: Reviewed-by: Matthew Rosato