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Date: Fri, 17 Jul 2026 12:48:12 +0200
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: leixiang <leixiang@kylinos.cn>
Cc: Bjorn Helgaas <bhelgaas@google.com>,
	Logan Gunthorpe <logang@deltatee.com>,
	Chaitanya Kulkarni <kch@nvidia.com>, Jens Axboe <axboe@kernel.dk>,
	linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] PCI/P2PDMA: Fix use-after-free in
 pci_p2pdma_add_resource() error path
Message-ID: <2026071700-chitchat-uninsured-0767@gregkh>
References: <20260717095120.51111-1-leixiang@kylinos.cn>
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In-Reply-To: <20260717095120.51111-1-leixiang@kylinos.cn>

On Fri, Jul 17, 2026 at 05:51:17PM +0800, leixiang wrote:
> In pci_p2pdma_add_resource(), a devm action is registered to call
> pci_p2pdma_unmap_mappings() with the 'p2p_pgmap' context. If the subsequent
> call to gen_pool_add_owner() fails, the code jumps to the 'pages_free'
> error path.
> 
> In this error path, 'p2p_pgmap' is explicitly freed via devm_kfree().
> However, the previously registered devm action is never removed. This
> leaves a dangling pointer in the device's devres list. When the device
> is unbound and devres is cleaning up resources, the unmap action will be
> called with the already-freed 'p2p_pgmap', resulting in a use-after-free
> bug.
> 
> Fix this by properly calling devm_remove_action() in the error path before
> freeing 'p2p_pgmap'.
> 
> Fixes: 7e9c7ef83d78 ("PCI/P2PDMA: Allow userspace VMA allocations through sysfs")
> Assisted-by: Antigravity:Gemini [tools]
> Signed-off-by: leixiang <leixiang@kylinos.cn>

We need a full name here, not just an email alias.

thanks,

greg k-h