syzbot report KMSAN: uninit-value in pick_link, this is because the corresponding folio was not found from the mapping, and the memory was not initialized when allocating a new folio for the filemap. To avoid the occurrence of kmsan report uninit-value, initialize the newly allocated folio memory to 0. Reported-and-tested-by: syzbot+24ac24ff58dc5b0d26b9@xxxxxxxxxxxxxxxxxxxxxxxxx Closes: https://syzkaller.appspot.com/bug?extid=24ac24ff58dc5b0d26b9 Signed-off-by: Lizhi Xu <lizhi.xu@xxxxxxxxxxxxx> --- mm/filemap.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/mm/filemap.c b/mm/filemap.c index 657bcd887fdb..1b22eab691e8 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -3753,6 +3753,11 @@ static struct folio *do_read_cache_folio(struct address_space *mapping, folio = filemap_alloc_folio(gfp, 0); if (!folio) return ERR_PTR(-ENOMEM); + + void *kaddr = kmap_local_folio(folio, 0); + memset(kaddr, 0, folio_size(folio)); + kunmap_local(kaddr); + err = filemap_add_folio(mapping, folio, index, gfp); if (unlikely(err)) { folio_put(folio); -- 2.43.0
