From 937d7b84dca58f2565715f2c8e52f14c3d65fb22 Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Fri, 2 Oct 2015 23:54:58 -0400 Subject: [PATCH] ext4 crypto: fix memory leak in ext4_bio_write_page() There are times when ext4_bio_write_page() is called even though we don't actually need to do any I/O. This happens when ext4_writepage() gets called by the jbd2 commit path when an inode needs to force its pages written out in order to provide data=ordered guarantees --- and a page is backed by an unwritten (e.g., uninitialized) block on disk, or if delayed allocation means the page's backing store hasn't been allocated yet. In that case, we need to skip the call to ext4_encrypt_page(), since in addition to wasting CPU, it leads to a bounce page and an ext4 crypto context getting leaked. Signed-off-by: Theodore Ts'o Cc: stable@vger.kernel.org --- fs/ext4/page-io.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/fs/ext4/page-io.c b/fs/ext4/page-io.c index 84ba4d2b3a35..17fbe3882b8e 100644 --- a/fs/ext4/page-io.c +++ b/fs/ext4/page-io.c @@ -425,6 +425,7 @@ int ext4_bio_write_page(struct ext4_io_submit *io, struct buffer_head *bh, *head; int ret = 0; int nr_submitted = 0; + int nr_to_submit = 0; blocksize = 1 << inode->i_blkbits; @@ -477,11 +478,13 @@ int ext4_bio_write_page(struct ext4_io_submit *io, unmap_underlying_metadata(bh->b_bdev, bh->b_blocknr); } set_buffer_async_write(bh); + nr_to_submit++; } while ((bh = bh->b_this_page) != head); bh = head = page_buffers(page); - if (ext4_encrypted_inode(inode) && S_ISREG(inode->i_mode)) { + if (ext4_encrypted_inode(inode) && S_ISREG(inode->i_mode) && + nr_to_submit) { data_page = ext4_encrypt(inode, page); if (IS_ERR(data_page)) { ret = PTR_ERR(data_page); -- 2.39.5