patch "Revert "kernfs: fix memleak in kernel_ops_readdir()"" added to driver-core-linus

patch "Revert "kernfs: fix memleak in kernel_ops_readdir()"" added to driver-core-linus

[gregkh]

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

    Revert "kernfs: fix memleak in kernel_ops_readdir()"

to my driver-core git tree which can be found at
    git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core.git
in the driver-core-linus branch.

The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.

If you have any questions about this process, please let me know.


From 8097c43bcbec56fbd0788d99e1e236c0e0d4013f Mon Sep 17 00:00:00 2001
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: Thu, 8 Aug 2019 08:39:35 +0200
Subject: Revert "kernfs: fix memleak in kernel_ops_readdir()"

This reverts commit cc798c83898ea0a77fcaa1a92afda35c3c3ded74.

Tony writes:
	Somehow this causes a regression in Linux next for me where I'm
	seeing lots of sysfs entries now missing under
	/sys/bus/platform/devices.

	For example, I now only see one .serial entry show up in sysfs.
	Things work again if I revert commit cc798c83898e ("kernfs: fix
	memleak inkernel_ops_readdir()"). Any ideas why that would be?

Tejun says:
	Ugh, you're right.  It can get double-put cuz ctx->pos is put by
	release too.

So reverting it for now.

Reported-by: Tony Lindgren <tony@atomide.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Fixes: cc798c83898e ("kernfs: fix memleak in kernel_ops_readdir()")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 fs/kernfs/dir.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c
index 1e98efc2bf6d..a387534c9577 100644
--- a/fs/kernfs/dir.c
+++ b/fs/kernfs/dir.c
@@ -1684,14 +1684,11 @@ static int kernfs_fop_readdir(struct file *file, struct dir_context *ctx)
 		kernfs_get(pos);
 
 		mutex_unlock(&kernfs_mutex);
-		if (unlikely(!dir_emit(ctx, name, len, ino, type))) {
-			kernfs_put(pos);
-			goto out;
-		}
+		if (!dir_emit(ctx, name, len, ino, type))
+			return 0;
 		mutex_lock(&kernfs_mutex);
 	}
 	mutex_unlock(&kernfs_mutex);
-out:
 	file->private_data = NULL;
 	ctx->pos = INT_MAX;
 	return 0;
-- 
2.22.0