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	Tue, 11 Mar 2025 00:35:54 +0000
Date: Tue, 11 Mar 2025 00:35:54 +0000
From: Al Viro <viro@zeniv.linux.org.uk>
To: Amit <amitchoudhary0523@gmail.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Catching use-after-free easily in linux kernel.
Message-ID: <20250311003554.GN2023217@ZenIV>
References: <CAFf+5zj=KmBG0Avqy6cq9qtpGKR3HnYNc6rK6y8B_78Ajt4RhQ@mail.gmail.com>
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Sender: Al Viro <viro@ftp.linux.org.uk>

On Mon, Mar 10, 2025 at 01:24:54PM +0530, Amit wrote:
> Hi,
> 
> We can catch use-after-free easily if we do the following:
> 
> kfree(x);
> (x) = NULL;
> 
> Now, if someone uses 'x' again then the kernel will crash and we will know where
> the use-after-free is happening and then we can fix it.

That assumes that no pointer is ever stored in more than one place.
Which is very clearly false.