On Thu, Mar 22, 2012 at 7:47 AM, James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx> wrote: > On Wed, 2012-03-21 at 23:32 -0700, Dan Williams wrote: >> In scsi at least two cases of the parent device being deleted before the >> child is added have been observed. >> >> 1/ scsi is performing async scans and the device is removed prior to the >> async can thread running. > > This doesn't sound right. We do an explicit get on the sdkp (and the > sdkp holds the sdp) before we schedule an async scan. That's only > removed after the async scan has completed, so it should be impossible > for the parent to vanish. Right, the parent does not get freed because we have a reference, but it still gets device_del()'d which leads to: device_del()->kobject_del()->sysfs_remove_dir() kobj->sd = NULL; ...and then sysfs_create_dir() (without this fix) goes ahead and de-references parent_sd via sysfs_ns_type(): return (sd->s_flags & SYSFS_NS_TYPE_MASK) >> SYSFS_NS_TYPE_SHIFT; -- Dan -- 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
