Miaohe Lin wrote: > On 2022/8/27 1:18, Dan Williams wrote: > > In the case where a filesystem is polled to take over the memory failure > > and receives -EOPNOTSUPP it indicates that page->index and page->mapping > > are valid for reverse mapping the failure address. Introduce > > FSDAX_INVALID_PGOFF to distinguish when add_to_kill() is being called > > from mf_dax_kill_procs() by a filesytem vs the typical memory_failure() > > path. > > Thanks for fixing. > I'm sorry but I can't find the bug report email. Report is here: https://lore.kernel.org/all/63069db388d43_1b3229426@xxxxxxxxxxxxxxxxxxxxxxxxx.notmuch/ > Do you mean mf_dax_kill_procs() can pass an invalid pgoff to the > add_to_kill()? No, the problem is that ->notify_failure() returns -EOPNOTSUPP so memory_failure_dev_pagemap() falls back to mf_generic_kill_procs(). However, mf_generic_kill_procs() end up passing '0' for fsdax_pgoff from collect_procs_file() to add_to_kill(). A '0' for fsdax_pgoff results in vma_pgoff_address() returning -EFAULT which causes the VM_BUG_ON() in dev_pagemap_mapping_shift().
