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From: Kalle Valo <kvalo@kernel.org>
To: Breno Leitao <leitao@debian.org>
Cc: kuba@kernel.org,  ath11k@lists.infradead.org,
  ath10k@lists.infradead.org,  linux-wireless@vger.kernel.org,
  imitsyanko@quantenna.com,  geomatsi@gmail.com,
  linux-kernel@vger.kernel.org,  netdev@vger.kernel.org
Subject: Re: [PATCH 0/3] wifi: Un-embed ath10k and ath11k dummy netdev
References: <20240405122123.4156104-1-leitao@debian.org>
	<87y19r264m.fsf@kernel.org> <ZhPyRHHlVot+a8Xq@gmail.com>
Date: Mon, 08 Apr 2024 19:43:42 +0300
In-Reply-To: <ZhPyRHHlVot+a8Xq@gmail.com> (Breno Leitao's message of "Mon, 8
	Apr 2024 06:33:56 -0700")
Message-ID: <87pluz24ap.fsf@kernel.org>
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Breno Leitao <leitao@debian.org> writes:

> Hello Kalle,
>
> On Fri, Apr 05, 2024 at 06:15:05PM +0300, Kalle Valo wrote:
>> Breno Leitao <leitao@debian.org> writes:
>> 
>> > struct net_device shouldn't be embedded into any structure, instead,
>> > the owner should use the private space to embed their state into
>> > net_device.
>> >
>> > This patch set fixes the problem above for ath10k and ath11k. This also
>> > fixes the conversion of qtnfmac driver to the new helper.
>> >
>> > This patch set depends on a series that is still under review:
>> > https://lore.kernel.org/all/20240404114854.2498663-1-leitao@debian.org/#t
>> >
>> > If it helps, I've pushed the tree to
>> > https://github.com/leitao/linux/tree/wireless-dummy
>> >
>> > PS: Due to lack of hardware, unfortunately all these patches are
>> > compiled tested only.
>> >
>> > Breno Leitao (3):
>> >   wifi: qtnfmac: Use netdev dummy allocator helper
>> >   wifi: ath10k: allocate dummy net_device dynamically
>> >   wifi: ath11k: allocate dummy net_device dynamically
>> 
>> Thanks for setting up the branch, that makes the testing very easy. I
>> now tested the branch using the commit below with ath11k WCN6855 hw2.0
>> on an x86 box:
>> 
>> 5be9a125d8e7 wifi: ath11k: allocate dummy net_device dynamically
>> 
>> But unfortunately it crashes, the stack trace below. I can easily test
>> your branches, just let me know what to test. A direct 'git pull'
>> command is the best.
>
> Thanks for the test.
>
> Reading the issue, I am afraid that freeing netdev explicitly
> (free_netdev()) might not be the best approach at the exit path.
>
> I would like to try to leverage the ->needs_free_netdev netdev
> mechanism to do the clean-up, if that makes sense. I've updated the
> ath11k patch, and I am curious if that is what we want.
>
> Would you mind testing a net patch I have, please?
>
>   https://github.com/leitao/linux/tree/wireless-dummy_v2

I tested this again with my WCN6855 hw2.0 x86 test box on this commit:

a87674ac820e wifi: ath11k: allocate dummy net_device dynamically

It passes my tests and doesn't crash, but I see this kmemleak warning a
lot:

unreferenced object 0xffff888127109400 (size 128):
  comm "insmod", pid 2813, jiffies 4294926528
  hex dump (first 32 bytes):
    d0 93 d5 0a 81 88 ff ff d0 93 d5 0a 81 88 ff ff  ................
    01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace (crc 870e4f12):
    [<ffffffff99bcd375>] kmemleak_alloc+0x45/0x80
    [<ffffffff975707a8>] kmalloc_trace+0x278/0x2c0
    [<ffffffff992904c5>] __hw_addr_create+0x55/0x260
    [<ffffffff992909cb>] __hw_addr_add_ex+0x2fb/0x6d0
    [<ffffffff99294004>] dev_addr_init+0x144/0x230
    [<ffffffff992629ee>] alloc_netdev_mqs+0x12e/0xfe0
    [<ffffffff992638c5>] alloc_netdev_dummy+0x25/0x30
    [<ffffffffc0b6b0cd>] ath11k_pcic_ext_irq_config+0x1ad/0xc10 [ath11k]
    [<ffffffffc0b6c431>] ath11k_pcic_config_irq+0x2f1/0x4b0 [ath11k]
    [<ffffffffc0cb8314>] ath11k_pci_probe+0x874/0x1210 [ath11k_pci]
    [<ffffffff97febf06>] local_pci_probe+0xd6/0x180
    [<ffffffff97feefaa>] pci_call_probe+0x15a/0x400
    [<ffffffff97ff03d6>] pci_device_probe+0xa6/0x100
    [<ffffffff98abe315>] really_probe+0x1d5/0x920
    [<ffffffff98abed48>] __driver_probe_device+0x2e8/0x3f0
    [<ffffffff98abee9a>] driver_probe_device+0x4a/0x140


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