https://bugzilla.kernel.org/show_bug.cgi?id=207383
--- Comment #12 from Duncan (1i5t5.duncan@cox.net) --- OK, bisect says:
4064b9827 Peter Xu mm: allow VM_FAULT_RETRY for multiple times
... which came in via akpm and touches drivers/drm/ttm/ttm_bo_vm.c.
But I'm not entirely confident in that result ATM. Among other things I had set ZSWAP_DEFAULT_ON for 5.7, and I had zswap configured but not active previously, so that could be it too. I'm not typically under enough memory pressure to trigger it, but...
Luckily a git show -R generated patch still applies cleanly on current master (5.7.0-rc4-00029-gdc56c5acd, tho I've only built it not rebooted to test it yet) so I can test both the commit-revert patch and the changed zswap options now.
So I'm confirming still.
But perhaps take another look at that commit and see if there's some way allowing unlimited VM_FAULT_RETRY could leave drm at least on on amdgpu eternally stalled, which does seem to fit the symptoms, whether it's unlimited VM_FAULT_RETRY or not.