Comment # 13 on bug 1205496 from Jan Kara

The fix has been merged upstream now as commit b40ebaf63851 ("ext4: avoid
BUG_ON when creating xattrs"). I've pushed the fix to SLE15-SP4 branch so it
should appear as part of maintenance update in January. It occurred to me now:
If you need it earlier, you can also install the kernel-of-the-day kernel from
https://download.opensuse.org/repositories/Kernel:/SLE15-SP4/pool/
The Thursday build or so should already contain the fix.

Thanks for your help debugging this! Closing the bug.