From: Jakub Kicinski <kuba@kernel.org>
To: Mina Almasry <almasrymina@google.com>
Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Paolo Abeni <pabeni@redhat.com>, Simon Horman <horms@kernel.org>,
Stanislav Fomichev <sdf@fomichev.me>
Subject: Re: [PATCH net-next v1] net: devmem: NULL check netdev_nl_get_dma_dev return value
Date: Fri, 29 Aug 2025 17:52:22 -0700 [thread overview]
Message-ID: <20250829175222.32d500ca@kernel.org> (raw)
In-Reply-To: <20250829220003.3310242-1-almasrymina@google.com>
On Fri, 29 Aug 2025 21:59:38 +0000 Mina Almasry wrote:
> netdev_nl_get_dma_dev can return NULL. This happens in the unlikely
> scenario that netdev->dev.parent is NULL, or all the calls to the
> ndo_queue_get_dma_dev return NULL from the driver.
I probably have Friday brain but I don't see what you mean..
In net-next net_devmem_bind_dmabuf() gets a dma_dev and returns
-EOPNOTSUPP PTR if its NULL.
> Current code doesn't NULL check the return value, so it may be passed to
> net_devmem_bind_dmabuf, which AFAICT will eventually hit
> WARN_ON(!dmabuf || !dev) in dma_buf_dynamic_attach and do a kernel
> splat. Avoid this scenario by using IS_ERR_OR_NULL in place of IS_ERR.
>
> Found by code inspection.
>
> Note that this was a problem even before the fixes patch, since we
> passed netdev->dev.parent to net_devmem_bind_dmabuf before NULL checking
> it anyway :( But that code got removed in the fixes patch (and retained
> the bug).
If the bug exists in net please send a fix for net, and ignore net-next.
Maintainers will cope with the merge.
next prev parent reply other threads:[~2025-08-30 0:52 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-08-29 21:59 [PATCH net-next v1] net: devmem: NULL check netdev_nl_get_dma_dev return value Mina Almasry
2025-08-29 22:02 ` Mina Almasry
2025-08-30 0:52 ` Jakub Kicinski [this message]
2025-09-02 15:54 ` Stanislav Fomichev
2025-09-02 16:14 ` Mina Almasry
2025-09-01 11:35 ` Dan Carpenter
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