Received-SPF: pass (google.com: domain of linux-kernel+bounces-102548-linux.lists.archive=gmail.com@vger.kernel.org designates 147.75.80.249 as permitted sender) client-ip=147.75.80.249;
Sender: Tejun Heo <htejun@gmail.com>
Date: Wed, 13 Mar 2024 11:44:32 -1000
From: Tejun Heo <tj@kernel.org>
To: Alan Stern <stern@rowland.harvard.edu>
Cc: Bart Van Assche <bvanassche@acm.org>,
	Greg KH <gregkh@linuxfoundation.org>,
	Kernel development list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] fs: sysfs: Fix reference leak in
 sysfs_break_active_protection()
Message-ID: <ZfIeQKluEeh7TulW@slm.duckdns.org>
References: <CAEkJfYO6jRVC8Tfrd_R=cjO0hguhrV31fDPrLrNOOHocDkPoAA@mail.gmail.com>
 <e9d710fc-eace-44de-b3cc-1117c3575ef7@rowland.harvard.edu>
 <2024030428-graph-harmful-1597@gregkh>
 <416a8311-c725-419a-8b22-74c80207347f@rowland.harvard.edu>
 <9c2484f4-df62-4d23-97a2-55a160eba55f@rowland.harvard.edu>
 <ZfIKwFSmw-ACj_jO@slm.duckdns.org>
 <8a4d3f0f-c5e3-4b70-a188-0ca433f9e6f9@rowland.harvard.edu>
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <8a4d3f0f-c5e3-4b70-a188-0ca433f9e6f9@rowland.harvard.edu>

On Wed, Mar 13, 2024 at 05:43:41PM -0400, Alan Stern wrote:
> The sysfs_break_active_protection() routine has an obvious reference
> leak in its error path.  If the call to kernfs_find_and_get() fails then
> kn will be NULL, so the companion sysfs_unbreak_active_protection()
> routine won't get called (and would only cause an access violation by
> trying to dereference kn->parent if it was called).  As a result, the
> reference to kobj acquired at the start of the function will never be
> released.
> 
> Fix the leak by adding an explicit kobject_put() call when kn is NULL.
> 
> Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
> Fixes: 2afc9166f79b ("scsi: sysfs: Introduce sysfs_{un,}break_active_protection()")
> Cc: Bart Van Assche <bvanassche@acm.org>
> Cc: <stable@vger.kernel.org>

Acked-by: Tejun Heo <tj@kernel.org>

Thanks.

-- 
tejun