Patch "ext4 crypto: fix memory leak in ext4_bio_write_page()" has been added to the 4.3-stable tree

This is a note to let you know that I've just added the patch titled

ext4 crypto: fix memory leak in ext4_bio_write_page()

to the 4.3-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
ext4-crypto-fix-memory-leak-in-ext4_bio_write_page.patch
and it can be found in the queue-4.3 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Theodore Ts'o <[email protected]>
Date: Fri, 2 Oct 2015 23:54:58 -0400
Subject: ext4 crypto: fix memory leak in ext4_bio_write_page()

From: Theodore Ts'o <[email protected]>

commit 937d7b84dca58f2565715f2c8e52f14c3d65fb22 upstream.

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.

---
 fs/ext4/page-io.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

@@ -425,6 +425,7 @@ int ext4_bio_write_page(struct ext4_io_s
 	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_s
 			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);

Patches currently in stable-queue which might be from [email protected] are

queue-4.3/ext4-jbd2-ensure-entering-into-panic-after-recording-an-error-in-superblock.patch queue-4.3/ext4-crypto-replace-some-bug_on-s-with-error-checks.patch queue-4.3/ext4-crypto-fix-bugs-in-ext4_encrypted_zeroout.patch queue-4.3/ext4-crypto-fix-memory-leak-in-ext4_bio_write_page.patch