From 80c739c4435707f5d680884e4d23245351cd16db Mon Sep 17 00:00:00 2001 From: Kent Overstreet Date: Wed, 13 Oct 2021 13:45:46 -0400 Subject: bcachefs: Don't allocate too-big bios This fixes a null ptr deref in bio_alloc_bioset() -> biovec_slab() Signed-off-by: Kent Overstreet --- fs/bcachefs/io.c | 2 ++ fs/bcachefs/util.c | 6 +++++- 2 files changed, 7 insertions(+), 1 deletion(-) diff --git a/fs/bcachefs/io.c b/fs/bcachefs/io.c index 8c0697bf7828..708ba5590182 100644 --- a/fs/bcachefs/io.c +++ b/fs/bcachefs/io.c @@ -782,6 +782,8 @@ static struct bio *bch2_write_bio_alloc(struct bch_fs *c, ? ((unsigned long) buf & (PAGE_SIZE - 1)) : 0), PAGE_SIZE); + pages = min(pages, BIO_MAX_VECS); + bio = bio_alloc_bioset(GFP_NOIO, pages, &c->bio_write); wbio = wbio_init(bio); wbio->put_bio = true; diff --git a/fs/bcachefs/util.c b/fs/bcachefs/util.c index 9f21f68e84d3..52de7c49cacb 100644 --- a/fs/bcachefs/util.c +++ b/fs/bcachefs/util.c @@ -525,7 +525,11 @@ int bch2_bio_alloc_pages(struct bio *bio, size_t size, gfp_t gfp_mask) if (!page) return -ENOMEM; - BUG_ON(!bio_add_page(bio, page, len, 0)); + if (unlikely(!bio_add_page(bio, page, len, 0))) { + __free_page(page); + break; + } + size -= len; } -- cgit v1.2.3