Hi, On Wed, Apr 13, 2016 at 11:14 PM, James Bottomley <jejb@xxxxxxxxxxxxxxxxxx> wrote: > On Wed, 2016-04-13 at 10:41 +0200, Johannes Thumshirn wrote: >> Hi Sergey, Xiong, >> >> Can you try below patch? >> >> On Montag, 11. April 2016 18:01:47 CEST Sergey Senozhatsky wrote: >> > Hello, >> > >> > commit 7b106f2de6938c31ce5e9c86bc70ad3904666b96 >> > Author: Johannes Thumshirn <jthumshirn@xxxxxxx> >> > Date: Tue Apr 5 11:50:44 2016 +0200 >> > >> > scsi: Add intermediate STARGET_REMOVE state to >> > scsi_target_state >> > >> > >> > BUG_ON()s (next-20160411) each time I remove a usb flash >> > >> > [ 49.561600] [<ffffffffa0087f42>] scsi_target_destroy+0x5a/0xcb >> > [scsi_mod] >> > [ 49.561607] [<ffffffffa0089099>] scsi_target_reap+0x4a/0x4f >> > [scsi_mod] >> > [ 49.561613] [<ffffffffa008b453>] __scsi_remove_device+0xc3/0xd0 >> > [scsi_mod] >> > [ 49.561619] [<ffffffffa0089d7b>] scsi_forget_host+0x52/0x63 >> > [scsi_mod] >> > [ 49.561623] [<ffffffffa0080dbc>] scsi_remove_host+0x8c/0x102 >> > [scsi_mod] >> > [ 49.561627] [<ffffffffa015c447>] usb_stor_disconnect+0x6b/0xab >> > [usb_storage] >> > [ 49.561634] [<ffffffffa0013f73>] >> > usb_unbind_interface+0x77/0x1ca [usbcore] >> > [ 49.561636] [<ffffffff813ae064>] >> > __device_release_driver+0x9d/0x121 >> > [ 49.561638] [<ffffffff813ae10b>] >> > device_release_driver+0x23/0x30 >> > [ 49.561639] [<ffffffff813ad2d1>] bus_remove_device+0xfb/0x10e >> > [ 49.561641] [<ffffffff813aac05>] device_del+0x164/0x1e6 >> > [ 49.561648] [<ffffffffa0011b09>] ? >> > remove_intf_ep_devs+0x3b/0x48 [usbcore] >> > [ 49.561655] [<ffffffffa001200e>] usb_disable_device+0x84/0x1a5 >> > [usbcore] >> > [ 49.561661] [<ffffffffa000ac7b>] usb_disconnect+0x94/0x19f >> > [usbcore] >> > [ 49.561667] [<ffffffffa000c2ab>] hub_event+0x5c1/0xdea >> > [usbcore] >> > [ 49.561670] [<ffffffff810530b1>] process_one_work+0x1dc/0x37f >> > [ 49.561672] [<ffffffff81053dc5>] worker_thread+0x282/0x36d >> > [ 49.561673] [<ffffffff81053b43>] ? rescuer_thread+0x2ae/0x2ae >> > [ 49.561675] [<ffffffff810580a8>] kthread+0xd2/0xda >> > [ 49.561678] [<ffffffff814bbf92>] ret_from_fork+0x22/0x40 >> > [ 49.561679] [<ffffffff81057fd6>] ? >> > kthread_worker_fn+0x13e/0x13e >> > >> > -ss >> > -- >> > To unsubscribe from this list: send the line "unsubscribe linux >> > -scsi" in >> > the body of a message to majordomo@xxxxxxxxxxxxxxx >> > More majordomo info at http://vger.kernel.org/majordomo-info.html >> > >> >> diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c >> index 0734927..0c00928 100644 >> --- a/drivers/scsi/scsi_sysfs.c >> +++ b/drivers/scsi/scsi_sysfs.c >> @@ -1276,6 +1276,7 @@ int scsi_sysfs_add_sdev(struct scsi_device >> *sdev) >> void __scsi_remove_device(struct scsi_device *sdev) >> { >> struct device *dev = &sdev->sdev_gendev; >> + struct scsi_target *starget; >> >> /* >> * This cleanup path is not reentrant and while it is >> impossible >> @@ -1315,7 +1316,9 @@ void __scsi_remove_device(struct scsi_device >> *sdev) >> * remoed sysfs visibility from the device, so make the >> target >> * invisible if this was the last device underneath it. >> */ >> - scsi_target_reap(scsi_target(sdev)); >> + starget = scsi_target(sdev); >> + starget->state = STARGET_REMOVE; >> + scsi_target_reap(starget); > > How about good grief no! A device with multiple targets will get it's > lists screwed with this > > The STARGET_REMOVE state you added only applies to the case we're > trying to kill a target. In the natural operation case, which is what > everyone else is running into, we will try to remove a running target > when it has no more scsi devices left on it. So the correct patch > should be to make the BUG_ON see this: > > James > > --- > > diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c > index 27df7e7..e0a78f5 100644 > --- a/drivers/scsi/scsi_scan.c > +++ b/drivers/scsi/scsi_scan.c > @@ -319,8 +319,7 @@ static void scsi_target_destroy(struct scsi_target *starget) > struct Scsi_Host *shost = dev_to_shost(dev->parent); > unsigned long flags; > > - BUG_ON(starget->state != STARGET_REMOVE && > - starget->state != STARGET_CREATED); > + BUG_ON(starget->state == STARGET_DEL); > starget->state = STARGET_DEL; > transport_destroy_device(dev); > spin_lock_irqsave(shost->host_lock, flags); > This will survive modprobe -r scsi_debug .. Just to make sure, is this _REMOVE state able to do the latter thing what it was trying to do, in this way ? commit 7b106f2de6938c31ce5e9c86bc70ad3904666b96 Author: Johannes Thumshirn <jthumshirn@xxxxxxx> Date: Tue Apr 5 11:50:44 2016 +0200 scsi: Add intermediate STARGET_REMOVE state to scsi_target_state Add intermediate STARGET_REMOVE state to scsi_target_state to avoid running into the BUG_ON() in scsi_target_reap(). The STARGET_REMOVE state is only valid in the path from scsi_remove_target() to scsi_target_destroy() indicating this target is going to be removed. This re-fixes the problem introduced in commits bc3f02a795d3 ("[SCSI] scsi_remove_target: fix softlockup regression on hot remove") and 40998193560d ("scsi: restart list search after unlock in scsi_remove_target") in a more comprehensive way. -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
