Date: Mon, 5 Mar 2012 18:46:29 GMT From: HPS <hselasky@c2i.net> To: freebsd-gnats-submit@FreeBSD.org Subject: kern/165740: SCSI code must drain callbacks before free Message-ID: <201203051846.q25IkTuN022061@red.freebsd.org> Resent-Message-ID: <201203051850.q25IoD8O072512@freefall.freebsd.org>
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>Number: 165740
>Category: kern
>Synopsis: SCSI code must drain callbacks before free
>Confidential: no
>Severity: critical
>Priority: medium
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Mon Mar 05 18:50:13 UTC 2012
>Closed-Date:
>Last-Modified:
>Originator: HPS
>Release: FreeBSD 8/9/10
>Organization:
>Environment:
FreeBSD 8.3-PRERELEASE amd64
>Description:
In /sys/cam/cam_xpt.c:
4569 void
4570 xpt_release_device(struct cam_ed *device)
4571 {
4572
4573 mjacob 224806 if (device->refcount == 1) {
4574 gibbs 39212 struct cam_devq *devq;
4575
4576 gibbs 44500 if (device->alloc_ccb_entry.pinfo.index != CAM_UNQUEUED_INDEX
4577 || device->send_ccb_entry.pinfo.index != CAM_UNQUEUED_INDEX)
4578 panic("Removing device while still queued for ccbs");
4579 gibbs 49927
4580 if ((device->flags & CAM_DEV_REL_TIMEOUT_PENDING) != 0)
Here callout_drain() should be used unconditionally. callout_drain() requires that the caller is not locked. I don't have enough information if it is possible to drop/pickup locks at this point in the code.
4581 mjacob 224806 callout_stop(&device->callout);
4583 mav 198748 TAILQ_REMOVE(&device->target->ed_entries, device,links);
4584 device->target->generation++;
4585 device->target->bus->sim->max_ccbs -= device->ccbq.devq_openings;
4586 trasz 186184 /* Release our slot in the devq */
4587 mav 198748 devq = device->target->bus->sim->devq;
4588 trasz 186184 cam_devq_resize(devq, devq->alloc_queue.array_size - 1);
4589 avatar 147571 camq_fini(&device->drvq);
4590 mav 198377 cam_ccbq_fini(&device->ccbq);
4591 ken 230590 /*
4592 * Free allocated memory. free(9) does nothing if the
4593 * supplied pointer is NULL, so it is safe to call without
4594 * checking.
4595 */
4596 free(device->supported_vpds, M_CAMXPT);
4597 free(device->device_id, M_CAMXPT);
4598 free(device->physpath, M_CAMXPT);
4599 free(device->rcap_buf, M_CAMXPT);
4600 free(device->serial_num, M_CAMXPT);
4601
4602 mav 198748 xpt_release_target(device->target);
4603 avatar 147723 free(device, M_CAMXPT);
--HPS
>How-To-Repeat:
>Fix:
>Release-Note:
>Audit-Trail:
>Unformatted:
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