linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Peter Ujfalusi <peter.ujfalusi@ti.com>
To: Al Viro <viro@zeniv.linux.org.uk>, <tytso@mit.edu>,
	<adilger.kernel@dilger.ca>
Cc: <linux-ext4@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
	<linux-fsdevel@vger.kernel.org>
Subject: [PATCH 1/2] fs: read_write: Check ->aio_write in __kernel_write() and vfs_write()
Date: Wed, 23 Apr 2014 16:46:45 +0300	[thread overview]
Message-ID: <1398260806-19340-2-git-send-email-peter.ujfalusi@ti.com> (raw)
In-Reply-To: <1398260806-19340-1-git-send-email-peter.ujfalusi@ti.com>

Do similar checks as it has been done in vfs_read for the aio_write
callback.
ext4 for example does not provide aio_write callback causing NULL pointer
dereference in do_sync_write() without this check.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
---
 fs/read_write.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/fs/read_write.c b/fs/read_write.c
index b6336a54f70d..009d8542a889 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -500,8 +500,10 @@ ssize_t __kernel_write(struct file *file, const char *buf, size_t count, loff_t
 		count =  MAX_RW_COUNT;
 	if (file->f_op->write)
 		ret = file->f_op->write(file, p, count, pos);
-	else
+	else if (file->f_op->aio_write)
 		ret = do_sync_write(file, p, count, pos);
+	else
+		ret = new_sync_write(file, p, count, pos);
 	set_fs(old_fs);
 	if (ret > 0) {
 		fsnotify_modify(file);
@@ -528,8 +530,10 @@ ssize_t vfs_write(struct file *file, const char __user *buf, size_t count, loff_
 		file_start_write(file);
 		if (file->f_op->write)
 			ret = file->f_op->write(file, buf, count, pos);
-		else
+		else if (file->f_op->aio_write)
 			ret = do_sync_write(file, buf, count, pos);
+		else
+			ret = new_sync_write(file, buf, count, pos);
 		if (ret > 0) {
 			fsnotify_modify(file);
 			add_wchar(current, ret);
-- 
1.9.2


  reply	other threads:[~2014-04-23 13:47 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-04-23 13:46 [PATCH 0/2] fs/ext4: fix for aio_write related kernel crash in linux-next Peter Ujfalusi
2014-04-23 13:46 ` Peter Ujfalusi [this message]
2014-04-23 13:46 ` [PATCH 2/2] ext4: Fix up the .write callback to use new_sync_write Peter Ujfalusi

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1398260806-19340-2-git-send-email-peter.ujfalusi@ti.com \
    --to=peter.ujfalusi@ti.com \
    --cc=adilger.kernel@dilger.ca \
    --cc=linux-ext4@vger.kernel.org \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=tytso@mit.edu \
    --cc=viro@zeniv.linux.org.uk \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).