From: Sebastian Ott Try to disable the old subchannel before we ask the driver core to move the attached device to a new parent. This way we can use the QUIESCE state during shutdown which prevents a possible use after free situation in some error cases. Signed-off-by: Sebastian Ott Signed-off-by: Martin Schwidefsky --- drivers/s390/cio/device.c | 24 ++++++++++++++++++++++-- 1 file changed, 22 insertions(+), 2 deletions(-) Index: quilt-2.6/drivers/s390/cio/device.c =================================================================== --- quilt-2.6.orig/drivers/s390/cio/device.c 2009-11-13 16:08:22.000000000 +0100 +++ quilt-2.6/drivers/s390/cio/device.c 2009-11-13 16:08:22.000000000 +0100 @@ -892,12 +892,27 @@ struct subchannel *sch) { struct subchannel *old_sch; - int rc; + int rc, old_enabled = 0; old_sch = to_subchannel(cdev->dev.parent); /* Obtain child reference for new parent. */ if (!get_device(&sch->dev)) return -ENODEV; + + if (!sch_is_pseudo_sch(old_sch)) { + spin_lock_irq(old_sch->lock); + old_enabled = old_sch->schib.pmcw.ena; + rc = 0; + if (old_enabled) + rc = cio_disable_subchannel(old_sch); + spin_unlock_irq(old_sch->lock); + if (rc == -EBUSY) { + /* Release child reference for new parent. */ + put_device(&sch->dev); + return rc; + } + } + mutex_lock(&sch->reg_mutex); rc = device_move(&cdev->dev, &sch->dev, DPM_ORDER_PARENT_BEFORE_DEV); mutex_unlock(&sch->reg_mutex); @@ -906,6 +921,12 @@ cdev->private->dev_id.ssid, cdev->private->dev_id.devno, sch->schid.ssid, sch->schib.pmcw.dev, rc); + if (old_enabled) { + /* Try to reenable the old subchannel. */ + spin_lock_irq(old_sch->lock); + cio_enable_subchannel(old_sch, (u32)(addr_t)old_sch); + spin_unlock_irq(old_sch->lock); + } /* Release child reference for new parent. */ put_device(&sch->dev); return rc; @@ -914,7 +935,6 @@ if (!sch_is_pseudo_sch(old_sch)) { spin_lock_irq(old_sch->lock); sch_set_cdev(old_sch, NULL); - cio_disable_subchannel(old_sch); spin_unlock_irq(old_sch->lock); css_schedule_eval(old_sch->schid); } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/