When running "find /", where / and /home are both btrfs filesystems, it segfaults, and the BUG occurs. A git bisect has shown that the bug is introduced in commit f0486c68e4bd9a06a5904d3eeb3a0d73a83befb8, which is pretty much the commit that introduced this function. The end-result is that everything that attempts to perform any I/O that touches the disk just hangs. Attached is the relevant snippet from my kern.log containing the stack trace.
Created attachment 26663 [details] Stack trace for BUG
Yan Zheng has this one fixed. I'll push it out. https://patchwork.kernel.org/patch/103235/
I've tested the patch and confirm it fixes the issue.
Handled-By : Yan Zheng <zheng.yan@oracle.com> Patch : https://patchwork.kernel.org/patch/103235/
Fixed by commit 3bf84a5a834d13e7c5c3e8e5b5c6b26012118dd8 .