diff options
| author | Matthew Wilcox (Oracle) <willy@infradead.org> | 2026-04-13 19:43:11 +0100 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2026-04-18 23:24:27 -0700 |
| commit | 615d9bb2ccad42f9e21d837431e401db2e471195 (patch) | |
| tree | a1b1a7b28eeff29f219a9870af8e28ab347f6a27 /mm | |
| parent | 8f5857be99f1ed1fa80991c72449541f634626ee (diff) | |
mm: call ->free_folio() directly in folio_unmap_invalidate()
We can only call filemap_free_folio() if we have a reference to (or hold a
lock on) the mapping. Otherwise, we've already removed the folio from the
mapping so it no longer pins the mapping and the mapping can be removed,
causing a use-after-free when accessing mapping->a_ops.
Follow the same pattern as __remove_mapping() and load the free_folio
function pointer before dropping the lock on the mapping. That lets us
make filemap_free_folio() static as this was the only caller outside
filemap.c.
Link: https://lore.kernel.org/20260413184314.3419945-1-willy@infradead.org
Fixes: fb7d3bc41493 ("mm/filemap: drop streaming/uncached pages when writeback completes")
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reported-by: Google Big Sleep <big-sleep-vuln-reports+bigsleep-501448199@google.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Jan Kara <jack@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/filemap.c | 3 | ||||
| -rw-r--r-- | mm/internal.h | 1 | ||||
| -rw-r--r-- | mm/truncate.c | 6 |
3 files changed, 7 insertions, 3 deletions
diff --git a/mm/filemap.c b/mm/filemap.c index 3c1e785542dd..793bf4816ea3 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -228,7 +228,8 @@ void __filemap_remove_folio(struct folio *folio, void *shadow) page_cache_delete(mapping, folio, shadow); } -void filemap_free_folio(struct address_space *mapping, struct folio *folio) +static void filemap_free_folio(const struct address_space *mapping, + struct folio *folio) { void (*free_folio)(struct folio *); diff --git a/mm/internal.h b/mm/internal.h index cb0af847d7d9..546114d3ee44 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -540,7 +540,6 @@ unsigned find_lock_entries(struct address_space *mapping, pgoff_t *start, pgoff_t end, struct folio_batch *fbatch, pgoff_t *indices); unsigned find_get_entries(struct address_space *mapping, pgoff_t *start, pgoff_t end, struct folio_batch *fbatch, pgoff_t *indices); -void filemap_free_folio(struct address_space *mapping, struct folio *folio); int truncate_inode_folio(struct address_space *mapping, struct folio *folio); bool truncate_inode_partial_folio(struct folio *folio, loff_t start, loff_t end); diff --git a/mm/truncate.c b/mm/truncate.c index 12467c1bd711..8617a12cb169 100644 --- a/mm/truncate.c +++ b/mm/truncate.c @@ -622,6 +622,7 @@ static int folio_launder(struct address_space *mapping, struct folio *folio) int folio_unmap_invalidate(struct address_space *mapping, struct folio *folio, gfp_t gfp) { + void (*free_folio)(struct folio *); int ret; VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio); @@ -648,9 +649,12 @@ int folio_unmap_invalidate(struct address_space *mapping, struct folio *folio, xa_unlock_irq(&mapping->i_pages); if (mapping_shrinkable(mapping)) inode_lru_list_add(mapping->host); + free_folio = mapping->a_ops->free_folio; spin_unlock(&mapping->host->i_lock); - filemap_free_folio(mapping, folio); + if (free_folio) + free_folio(folio); + folio_put_refs(folio, folio_nr_pages(folio)); return 1; failed: xa_unlock_irq(&mapping->i_pages); |