Re: [PATCH 5.4 000/215] 5.4.274-rc1 review

[Guenter Roeck]

On Thu, Apr 11, 2024 at 11:53:29AM +0200, Greg Kroah-Hartman wrote:
> This is the start of the stable review cycle for the 5.4.274 release.
> There are 215 patches in this series, all will be posted as a response
> to this one.  If anyone has any issues with these being applied, please
> let me know.
> 
> Responses should be made by Sat, 13 Apr 2024 09:53:55 +0000.
> Anything received after that time might be too late.
> 
[ ... ]
> 
> Sean Christopherson <seanjc@xxxxxxxxxx>
>     KVM: Always flush async #PF workqueue when vCPU is being destroyed
> 

This backport is bad. In kvm_setup_async_pf(), it removes a call to
kvm_get_kvm(). However, it does not remove the call to kvm_put_kvm()
in its error handler. Also see upstream commit 7863e346e108 ("KVM:
async_pf: Cleanup kvm_setup_async_pf()") which explains that one of
the error paths in kvm_setup_async_pf() which is not supposed to be
observed can be observed after all.

Guenter