linux-kernel - Re: [PATCH] fuse: add missing iput() in fuse

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Message-ID: <20251219221031.GZ1712166@ZenIV>
Date: Fri, 19 Dec 2025 22:10:31 +0000
From: Al Viro <viro@...iv.linux.org.uk>
To: Luis Henriques <luis@...lia.com>
Cc: Miklos Szeredi <miklos@...redi.hu>, mszeredi@...e.cz,
	linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
	kernel-dev@...lia.com
Subject: Re: [PATCH] fuse: add missing iput() in fuse_lookup() error path

On Fri, Dec 19, 2025 at 05:43:09PM +0000, Luis Henriques wrote:
> The inode use count needs to be dropped in the fuse_lookup() error path,
> when there's an error returned by d_splice_alias().
> 
> (While there, remove extra white spaces before labels.)
> 
> Fixes: 5835f3390e35 ("fuse: use d_materialise_unique()")
> Signed-off-by: Luis Henriques <luis@...lia.com>

Have you actually looked at d_splice_alias()?

It does consume inode reference in all cases, success or error.  On success
it gets transferred to dentry; on failure it is dropped.  That's quite
deliberate, since it makes life much simplier for failure handling in the
callers.

If you can reproduce a leak there, I would like to see a reproducer.
If not, I would say that your patch introduces a double-iput.

NAK.