On Mon, 1 Jan 2024 14:11:02 +0000 Matthew Wilcox > > From an mm point of view, what is implicit is that truncate calls > unmap_mapping_folio -> unmap_mapping_range_tree -> > unmap_mapping_range_vma -> zap_page_range_single -> unmap_single_vma -> > unmap_page_range -> zap_p4d_range -> zap_pud_range -> zap_pmd_range -> > zap_pte_range -> pte_offset_map_lock() > > So a truncate will take the page lock, then spin on the pte lock > until the racing munmap() has finished (ok, this was an exit(), not > a munmap(), but exit() does an implicit munmap()). > But ptl fails to explain the warning reported, while the sequence in __block_commit_write() mark_buffer_dirty(); folio_mark_uptodate(); hints the warning is bogus.
