| Message ID | 20241102014211.348731-1-ming.lei@redhat.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | lib/iov_iter: fix bvec iterator setup | expand |
On 11/1/24 7:42 PM, Ming Lei wrote: > .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 <edumazet@google.com> > 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 <ming.lei@redhat.com> > --- > Hi Jens, > > If possible, please merge this one with Eric's commit. I can just swap them out.
diff --git a/lib/iov_iter.c b/lib/iov_iter.c index 3026bdcb4738..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); @@ -1724,10 +1724,6 @@ static ssize_t iov_iter_extract_bvec_pages(struct iov_iter *i, (*pages)[k++] = bv.bv_page; size += bv.bv_len; - if (size >= maxsize) { - size = maxsize; - break; - } if (k >= maxpages) break;
.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 <edumazet@google.com> 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 <ming.lei@redhat.com> --- Hi Jens, If possible, please merge this one with Eric's commit. lib/iov_iter.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-)