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Message-Id: <1192993396.3661.1.camel@lov.site> Date: Sun, 21 Oct 2007 21:03:16 +0200 From: Kay Sievers <kay.sievers@...y.org> To: Alan Stern <stern@...land.harvard.edu> Cc: Greg KH <greg@...ah.com>, Kernel development list <linux-kernel@...r.kernel.org> Subject: Re: BUG in: Driver core: convert block from raw kobjects to core devices On Sat, 2007-10-20 at 21:33 -0400, Alan Stern wrote: > On Sat, 20 Oct 2007, Kay Sievers wrote: > > > Here is what I see, the error handler hangs without the final put and > > the kobject never gets cleaned up. Note the missing: > > kobject sdb: cleaning up > > > > What is your CONFIG_SYSFS_DEPRECATED option? I have it unset, and that > > may be the difference in the behavior if you have it set. > > It's unset in my config also. No, the difference lies somewhere else. > The plug-in parts are the same, but we differ in the remove parts. On > your system, unlink_gendisk ends up dropping only one reference instead > of two. This suggests that something strange is happening to the > request_queue on your machine. > > Can you try running the attached patch (without the previous patch)? > It traces the various release routines. The idea is that both the > scsi_disk and the scsi_device hold references to the request_queue, > and these references get dropped in their respective release routines. Here is the output. I used a device with a partition now, like your setup, but it's still the same difference to the behavior you see. What's your event sequence? Here is the output of "udevmonitor -k": UEVENT[1192992135.385043] add /devices/pci0000:00/0000:00:1d.7/usb2/2-2 (usb) UEVENT[1192992135.385088] add /devices/pci0000:00/0000:00:1d.7/usb2/2-2/usb_endpoint/usbdev2.7_ep00 (usb_endpoint) UEVENT[1192992135.385244] add /devices/pci0000:00/0000:00:1d.7/usb2/2-2/2-2:1.0 (usb) UEVENT[1192992135.385761] add /class/scsi_host/host8 (scsi_host) UEVENT[1192992135.386199] add /devices/pci0000:00/0000:00:1d.7/usb2/2-2/2-2:1.0/usb_endpoint/usbdev2.7_ep02 (usb_endpoint) UEVENT[1192992135.386212] add /devices/pci0000:00/0000:00:1d.7/usb2/2-2/2-2:1.0/usb_endpoint/usbdev2.7_ep86 (usb_endpoint) UEVENT[1192992135.386220] add /devices/pci0000:00/0000:00:1d.7/usb2/2-2/2-2:1.0/usb_endpoint/usbdev2.7_ep81 (usb_endpoint) UEVENT[1192992140.387147] add /devices/pci0000:00/0000:00:1d.7/usb2/2-2/2-2:1.0/host8/target8:0:0/8:0:0:0 (scsi) UEVENT[1192992140.387181] add /class/scsi_disk/8:0:0:0 (scsi_disk) UEVENT[1192992140.441760] add /devices/pci0000:00/0000:00:1d.7/usb2/2-2/2-2:1.0/host8/target8:0:0/8:0:0:0/block/sdb (block) UEVENT[1192992140.441776] add /devices/pci0000:00/0000:00:1d.7/usb2/2-2/2-2:1.0/host8/target8:0:0/8:0:0:0/block/sdb/sdb1 (block) UEVENT[1192992140.441785] add /class/scsi_device/8:0:0:0 (scsi_device) UEVENT[1192992140.441792] add /class/scsi_generic/sg2 (scsi_generic) UEVENT[1192992140.441800] add /class/bsg/8:0:0:0 (bsg) UEVENT[1192992143.163514] remove /devices/pci0000:00/0000:00:1d.7/usb2/2-2/2-2:1.0/usb_endpoint/usbdev2.7_ep02 (usb_endpoint) UEVENT[1192992143.163529] remove /devices/pci0000:00/0000:00:1d.7/usb2/2-2/2-2:1.0/usb_endpoint/usbdev2.7_ep86 (usb_endpoint) UEVENT[1192992143.163537] remove /devices/pci0000:00/0000:00:1d.7/usb2/2-2/2-2:1.0/usb_endpoint/usbdev2.7_ep81 (usb_endpoint) UEVENT[1192992143.163544] remove /class/bsg/8:0:0:0 (bsg) UEVENT[1192992143.163551] remove /class/scsi_generic/sg2 (scsi_generic) UEVENT[1192992143.163559] remove /class/scsi_device/8:0:0:0 (scsi_device) UEVENT[1192992143.163846] remove /class/scsi_disk/8:0:0:0 (scsi_disk) UEVENT[1192992143.163858] remove /devices/pci0000:00/0000:00:1d.7/usb2/2-2/2-2:1.0/host8/target8:0:0/8:0:0:0/block/sdb/sdb1 (block) UEVENT[1192992143.163866] remove /devices/pci0000:00/0000:00:1d.7/usb2/2-2/2-2:1.0/host8/target8:0:0/8:0:0:0/block/sdb (block) UEVENT[1192992143.163873] remove /devices/pci0000:00/0000:00:1d.7/usb2/2-2/2-2:1.0/host8/target8:0:0/8:0:0:0 (scsi) UEVENT[1192992143.163881] remove /class/scsi_host/host8 (scsi_host) UEVENT[1192992143.163889] remove /devices/pci0000:00/0000:00:1d.7/usb2/2-2/2-2:1.0 (usb) UEVENT[1192992143.163996] remove /devices/pci0000:00/0000:00:1d.7/usb2/2-2/usb_endpoint/usbdev2.7_ep00 (usb_endpoint) UEVENT[1192992143.164290] remove /devices/pci0000:00/0000:00:1d.7/usb2/2-2 (usb) > Just for the record, here's what happens with this patch on my system, > without the put_device call in del_gendisk (the patch comments it out). > I plugged in a USB drive and let things settle down. Then unplugging > the drive gave this: > > [ 457.916995] usb 6-4: USB disconnect, address 3 > [ 457.918459] usb 6-4: unregistering device > [ 457.920570] usb 6-4: usb_disable_device nuking all URBs > [ 457.920859] usb 6-4: unregistering interface 6-4:1.0 > [ 457.958990] disk_release: kobj cedcda50 > > The line above refers to the /dev/sda1 partition. Ignore it. > > [ 458.012317] del_gendisk sda, kobj ce8be990, queue cd9b2000, refcount before put_device 2 > > 2 references: one from the scsi_disk and one from the request_queue. > > [ 458.013133] scsi_disk_release: disk sda, kobj ce8be990, refcount before put_disk 2 > [ 458.032420] scsi_device_dev_release: rq cd9b2000 Hmm, I still don't see this without the final put. > These lines show where the two references to the request_queue get > dropped. As a result the queue is released, causing the gendisk to be > released as well: > > [ 458.032766] blk_release_queue: rq cd9b2000, parent ce8be990 > [ 458.032973] disk_release: kobj ce8be990 > [ 458.051641] usb 6-4:1.0: uevent > [ 458.052001] usb 6-4:1.0: uevent > [ 458.068665] usb 6-4: uevent > > If you don't get a similar sequence of events, it must indicate that > something on your system continues to hold an outstanding reference. > Maybe an automounter program, or something like that. I killed all userspace while catching that output. kobject <NULL>: cleaning up usb 1-2: new full speed USB device using uhci_hcd and address 4 kobject 1-2: registering. parent: usb1, set: devices kobject_uevent_env fill_kobj_path: path = '/devices/pci0000:00/0000:00:1d.0/usb1/1-2' kobject usb_endpoint: registering. parent: 1-2, set: <NULL> kobject_uevent_env unset subsystem caused the event to drop! kobject usbdev1.4_ep00: registering. parent: usb_endpoint, set: devices kobject_uevent_env fill_kobj_path: path = '/devices/pci0000:00/0000:00:1d.0/usb1/1-2/usb_endpoint/usbdev1.4_ep00' usb 1-2: configuration #1 chosen from 1 choice kobject 1-2:1.0: registering. parent: 1-2, set: devices kobject_uevent_env fill_kobj_path: path = '/devices/pci0000:00/0000:00:1d.0/usb1/1-2/1-2:1.0' scsi9 : SCSI emulation for USB Mass Storage devices kobject host9: registering. parent: 1-2:1.0, set: devices kobject_uevent_env kobject filter function caused the event to drop! kobject host9: registering. parent: scsi_host, set: class_obj kobject_uevent_env fill_kobj_path: path = '/class/scsi_host/host9' fill_kobj_path: path = '/devices/pci0000:00/0000:00:1d.0/usb1/1-2/1-2:1.0/host9' kobject usb_endpoint: registering. parent: 1-2:1.0, set: <NULL> kobject_uevent_env unset subsystem caused the event to drop! kobject usbdev1.4_ep82: registering. parent: usb_endpoint, set: devices kobject_uevent_env fill_kobj_path: path = '/devices/pci0000:00/0000:00:1d.0/usb1/1-2/1-2:1.0/usb_endpoint/usbdev1.4_ep82' kobject usbdev1.4_ep01: registering. parent: usb_endpoint, set: devices kobject_uevent_env fill_kobj_path: path = '/devices/pci0000:00/0000:00:1d.0/usb1/1-2/1-2:1.0/usb_endpoint/usbdev1.4_ep01' usb 1-2: new device found, idVendor=08ec, idProduct=0011 usb 1-2: new device strings: Mfr=1, Product=2, SerialNumber=3 usb 1-2: Product: USB 2.0 Memory Key usb 1-2: Manufacturer: IBM usb 1-2: SerialNumber: 0218B301030027E8 usb-storage: device found at 4 usb-storage: waiting for device to settle before scanning kobject target9:0:0: registering. parent: host9, set: devices kobject_uevent_env kobject filter function caused the event to drop! scsi 9:0:0:0: Direct-Access IBM Memory Key 3.04 PQ: 0 ANSI: 0 CCS kobject 9:0:0:0: registering. parent: target9:0:0, set: devices kobject_uevent_env fill_kobj_path: path = '/devices/pci0000:00/0000:00:1d.0/usb1/1-2/1-2:1.0/host9/target9:0:0/9:0:0:0' kobject 9:0:0:0: registering. parent: scsi_disk, set: class_obj kobject_uevent_env fill_kobj_path: path = '/class/scsi_disk/9:0:0:0' fill_kobj_path: path = '/devices/pci0000:00/0000:00:1d.0/usb1/1-2/1-2:1.0/host9/target9:0:0/9:0:0:0' sd 9:0:0:0: [sdb] 127840 512-byte hardware sectors (65 MB) sd 9:0:0:0: [sdb] Write Protect is off sd 9:0:0:0: [sdb] Mode Sense: 45 00 00 08 sd 9:0:0:0: [sdb] Assuming drive cache: write through kobject block: registering. parent: 9:0:0:0, set: <NULL> kobject_uevent_env unset subsystem caused the event to drop! kobject sdb: registering. parent: block, set: devices kobject_uevent_env kobject filter function caused the event to drop! kobject holders: registering. parent: sdb, set: <NULL> kobject_uevent_env kobject filter function caused the event to drop! kobject slaves: registering. parent: sdb, set: <NULL> kobject_uevent_env kobject filter function caused the event to drop! sd 9:0:0:0: [sdb] 127840 512-byte hardware sectors (65 MB) sd 9:0:0:0: [sdb] Write Protect is off sd 9:0:0:0: [sdb] Mode Sense: 45 00 00 08 sd 9:0:0:0: [sdb] Assuming drive cache: write through sdb: sdb1 kobject sdb1: registering. parent: sdb, set: devices kobject_uevent_env kobject filter function caused the event to drop! kobject holders: registering. parent: sdb1, set: <NULL> kobject_uevent_env kobject filter function caused the event to drop! kobject_uevent_env fill_kobj_path: path = '/devices/pci0000:00/0000:00:1d.0/usb1/1-2/1-2:1.0/host9/target9:0:0/9:0:0:0/block/sdb' kobject_uevent_env fill_kobj_path: path = '/devices/pci0000:00/0000:00:1d.0/usb1/1-2/1-2:1.0/host9/target9:0:0/9:0:0:0/block/sdb/sdb1' kobject queue: registering. parent: sdb, set: <NULL> kobject_uevent_env kobject filter function caused the event to drop! kobject iosched: registering. parent: queue, set: <NULL> kobject_uevent_env kobject filter function caused the event to drop! sd 9:0:0:0: [sdb] Attached SCSI removable disk kobject 9:0:0:0: registering. parent: scsi_device, set: class_obj kobject_uevent_env fill_kobj_path: path = '/class/scsi_device/9:0:0:0' fill_kobj_path: path = '/devices/pci0000:00/0000:00:1d.0/usb1/1-2/1-2:1.0/host9/target9:0:0/9:0:0:0' kobject sg2: registering. parent: scsi_generic, set: class_obj kobject_uevent_env fill_kobj_path: path = '/class/scsi_generic/sg2' fill_kobj_path: path = '/devices/pci0000:00/0000:00:1d.0/usb1/1-2/1-2:1.0/host9/target9:0:0/9:0:0:0' sd 9:0:0:0: Attached scsi generic sg2 type 0 kobject 9:0:0:0: registering. parent: bsg, set: class_obj kobject_uevent_env fill_kobj_path: path = '/class/bsg/9:0:0:0' fill_kobj_path: path = '/devices/pci0000:00/0000:00:1d.0/usb1/1-2/1-2:1.0/host9/target9:0:0/9:0:0:0' kobject <NULL>: cleaning up scsi_device_dev_release: rq ffff810005518690 kobject iosched: cleaning up kobject queue: cleaning up blk_release_queue: rq ffff810005518690, parent 0000000000000000 kobject target9:0:1: registering. parent: host9, set: devices kobject_uevent_env kobject filter function caused the event to drop! kobject <NULL>: cleaning up scsi_device_dev_release: rq ffff810005518690 kobject iosched: cleaning up kobject queue: cleaning up blk_release_queue: rq ffff810005518690, parent 0000000000000000 kobject_uevent_env kobject filter function caused the event to drop! kobject target9:0:1: cleaning up kobject target9:0:2: registering. parent: host9, set: devices kobject_uevent_env kobject filter function caused the event to drop! kobject <NULL>: cleaning up scsi_device_dev_release: rq ffff810005518690 kobject iosched: cleaning up kobject queue: cleaning up blk_release_queue: rq ffff810005518690, parent 0000000000000000 kobject_uevent_env kobject filter function caused the event to drop! kobject target9:0:2: cleaning up kobject target9:0:3: registering. parent: host9, set: devices kobject_uevent_env kobject filter function caused the event to drop! kobject <NULL>: cleaning up scsi_device_dev_release: rq ffff810005518690 kobject iosched: cleaning up kobject queue: cleaning up blk_release_queue: rq ffff810005518690, parent 0000000000000000 kobject_uevent_env kobject filter function caused the event to drop! kobject target9:0:3: cleaning up kobject target9:0:4: registering. parent: host9, set: devices kobject_uevent_env kobject filter function caused the event to drop! kobject <NULL>: cleaning up scsi_device_dev_release: rq ffff810005518690 kobject iosched: cleaning up kobject queue: cleaning up blk_release_queue: rq ffff810005518690, parent 0000000000000000 kobject_uevent_env kobject filter function caused the event to drop! kobject target9:0:4: cleaning up kobject target9:0:5: registering. parent: host9, set: devices kobject_uevent_env kobject filter function caused the event to drop! kobject <NULL>: cleaning up scsi_device_dev_release: rq ffff810005518690 kobject iosched: cleaning up kobject queue: cleaning up blk_release_queue: rq ffff810005518690, parent 0000000000000000 kobject_uevent_env kobject filter function caused the event to drop! kobject target9:0:5: cleaning up kobject target9:0:6: registering. parent: host9, set: devices kobject_uevent_env kobject filter function caused the event to drop! kobject <NULL>: cleaning up scsi_device_dev_release: rq ffff810005518690 kobject iosched: cleaning up kobject queue: cleaning up blk_release_queue: rq ffff810005518690, parent 0000000000000000 kobject_uevent_env kobject filter function caused the event to drop! kobject target9:0:6: cleaning up kobject target9:0:7: registering. parent: host9, set: devices kobject_uevent_env kobject filter function caused the event to drop! kobject <NULL>: cleaning up scsi_device_dev_release: rq ffff810005518690 kobject iosched: cleaning up kobject queue: cleaning up blk_release_queue: rq ffff810005518690, parent 0000000000000000 kobject_uevent_env kobject filter function caused the event to drop! kobject target9:0:7: cleaning up usb-storage: device scan complete usb 1-2: USB disconnect, address 4 kobject_uevent_env fill_kobj_path: path = '/devices/pci0000:00/0000:00:1d.0/usb1/1-2/1-2:1.0/usb_endpoint/usbdev1.4_ep82' kobject usbdev1.4_ep82: cleaning up kobject_uevent_env fill_kobj_path: path = '/devices/pci0000:00/0000:00:1d.0/usb1/1-2/1-2:1.0/usb_endpoint/usbdev1.4_ep01' kobject usbdev1.4_ep01: cleaning up kobject usb_endpoint: cleaning up kobject_uevent_env fill_kobj_path: path = '/class/bsg/9:0:0:0' fill_kobj_path: path = '/devices/pci0000:00/0000:00:1d.0/usb1/1-2/1-2:1.0/host9/target9:0:0/9:0:0:0' kobject 9:0:0:0: cleaning up kobject_uevent_env fill_kobj_path: path = '/class/scsi_generic/sg2' fill_kobj_path: path = '/devices/pci0000:00/0000:00:1d.0/usb1/1-2/1-2:1.0/host9/target9:0:0/9:0:0:0' kobject sg2: cleaning up kobject <NULL>: cleaning up kobject <NULL>: cleaning up disk_release: kobj ffff810003bcbd58 kobject_uevent_env fill_kobj_path: path = '/class/scsi_device/9:0:0:0' fill_kobj_path: path = '/devices/pci0000:00/0000:00:1d.0/usb1/1-2/1-2:1.0/host9/target9:0:0/9:0:0:0' kobject 9:0:0:0: cleaning up kobject_uevent_env fill_kobj_path: path = '/class/scsi_disk/9:0:0:0' fill_kobj_path: path = '/devices/pci0000:00/0000:00:1d.0/usb1/1-2/1-2:1.0/host9/target9:0:0/9:0:0:0' kobject holders: unregistering kobject_uevent_env kobject filter function caused the event to drop! kobject holders: cleaning up kobject_uevent_env fill_kobj_path: path = '/devices/pci0000:00/0000:00:1d.0/usb1/1-2/1-2:1.0/host9/target9:0:0/9:0:0:0/block/sdb/sdb1' kobject sdb1: cleaning up kobject_uevent_env kobject filter function caused the event to drop! kobject_uevent_env kobject filter function caused the event to drop! kobject holders: unregistering kobject_uevent_env kobject filter function caused the event to drop! kobject holders: cleaning up kobject slaves: unregistering kobject_uevent_env kobject filter function caused the event to drop! kobject slaves: cleaning up kobject_uevent_env fill_kobj_path: path = '/devices/pci0000:00/0000:00:1d.0/usb1/1-2/1-2:1.0/host9/target9:0:0/9:0:0:0/block/sdb' del_gendisk sdb, kobj ffff810004825158, queue ffff810005518000, refcount before put_device 2 kobject 9:0:0:0: cleaning up scsi_disk_release: disk sdb, kobj ffff810004825158, refcount before put_disk 2 kobject_uevent_env fill_kobj_path: path = '/devices/pci0000:00/0000:00:1d.0/usb1/1-2/1-2:1.0/host9/target9:0:0/9:0:0:0' kobject_uevent_env fill_kobj_path: path = '/class/scsi_host/host9' fill_kobj_path: path = '/devices/pci0000:00/0000:00:1d.0/usb1/1-2/1-2:1.0/host9' kobject host9: cleaning up kobject_uevent_env kobject filter function caused the event to drop! kobject_uevent_env fill_kobj_path: path = '/devices/pci0000:00/0000:00:1d.0/usb1/1-2/1-2:1.0' kobject_uevent_env fill_kobj_path: path = '/devices/pci0000:00/0000:00:1d.0/usb1/1-2/usb_endpoint/usbdev1.4_ep00' kobject usbdev1.4_ep00: cleaning up kobject usb_endpoint: cleaning up kobject_uevent_env fill_kobj_path: path = '/devices/pci0000:00/0000:00:1d.0/usb1/1-2' Thanks, Kay - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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