RE: [PATCH net,v3] net: mana: Fix accessing freed irq affinity_hint

-----Original Message-----
From: Jakub Kicinski <kuba@kernel.org>
Sent: Monday, February 6, 2023 9:33 PM
To: Haiyang Zhang <haiyangz@microsoft.com>
Cc: linux-hyperv@vger.kernel.org; netdev@vger.kernel.org; Dexuan Cui
[off-list ref]; KY Srinivasan [off-list ref]; Paul Rosswurm
[off-list ref]; olaf@aepfle.de; vkuznets@redhat.com;
davem@davemloft.net; wei.liu@kernel.org; edumazet@google.com;
pabeni@redhat.com; leon@kernel.org; Long Li [off-list ref];
ssengar@linux.microsoft.com; linux-kernel@vger.kernel.org;
stable@vger.kernel.org
Subject: Re: [PATCH net,v3] net: mana: Fix accessing freed irq affinity_hint

On Mon,  6 Feb 2023 13:28:49 -0800 Haiyang Zhang wrote:

quoted

After calling irq_set_affinity_and_hint(), the cpumask pointer is
saved in desc->affinity_hint, and will be used later when reading
/proc/irq/<num>/affinity_hint. So the cpumask variable needs to be
persistent. Otherwise, we are accessing freed memory when reading
the affinity_hint file.

Also, need to clear affinity_hint before free_irq(), otherwise there
is a one-time warning and stack trace during module unloading:

What's the difference from the previous posting? Did you just resend it?

Previously, it failed the auto-check due to some people were not CC-ed.
I resent it with more CCs.

Thanks,
- Haiyang