From 341468e0ab4bb1b26ad0b0cee7c6db4bf283043a Mon Sep 17 00:00:00 2001 From: Ming Lei Date: Sat, 2 Nov 2024 09:42:11 +0800 Subject: [PATCH] lib/iov_iter: fix bvec iterator setup .bi_size of bvec iterator should be initialized as real max size for walking, and .bi_bvec_done just counts how many bytes need to be skipped in the 1st bvec, so .bi_size isn't related with .bi_bvec_done. This patch fixes bvec iterator initialization, and the inner `size` check isn't needed any more, so revert Eric Dumazet's commit 7bc802acf193 ("iov-iter: do not return more bytes than requested in iov_iter_extract_bvec_pages()"). Cc: Eric Dumazet Fixes: e4e535bff2bc ("iov_iter: don't require contiguous pages in iov_iter_extract_bvec_pages") Reported-by: syzbot+71abe7ab2b70bca770fd@syzkaller.appspotmail.com Tested-by: syzbot+71abe7ab2b70bca770fd@syzkaller.appspotmail.com Signed-off-by: Ming Lei Signed-off-by: Jens Axboe --- lib/iov_iter.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/lib/iov_iter.c b/lib/iov_iter.c index c761f6db3cb4..4a54c7af62c0 100644 --- a/lib/iov_iter.c +++ b/lib/iov_iter.c @@ -1700,7 +1700,7 @@ static ssize_t iov_iter_extract_bvec_pages(struct iov_iter *i, skip = 0; } bi.bi_idx = 0; - bi.bi_size = maxsize + skip; + bi.bi_size = maxsize; bi.bi_bvec_done = skip; maxpages = want_pages_array(pages, maxsize, skip, maxpages); -- 2.50.1