>On Thu, Sep 02, 2021 at 01:57:13PM +0000, Christian L?hle wrote: >> sd and parent devices must not be removed as sd_open checks for events >> >> sd_need_revalidate and sd_revalidate_disk traverse the device path >> to check for event changes. If during this, e.g. the scsi host is being >> removed and its resources freed, this traversal crashes. >> Locking with scan_mutex for just a scsi disk open may seem blunt, but there >> does not seem to be a more granular option. Also opening /dev/sdX directly >> happens rarely enough that this shouldn't cause any issues. > > Can you please root cause how the device could not be valid, as that > should not happen? The device is being removed physically, the driver e.g. uas calls scsi_remove_host while user-space opens the /dev/sdX. >> >> The issue occurred on an older kernel with the following trace: >> stack segment: 0000 [#1] PREEMPT SMP PTI >> CPU: 1 PID: 121457 Comm: python3 Not tainted 4.14.238hyLinux #1 > > .. preferably with a current mainline kernel as things changed a lot > in this area. I will, but might take a while to get a setup to reproduce the issue. (The setup where this occurred actually powerfails the usb device repreatedly.)= Hyperstone GmbH | Line-Eid-Strasse 3 | 78467 Konstanz Managing Directors: Dr. Jan Peter Berns. Commercial register of local courts: Freiburg HRB381782
