Subject: Re: [v2] cxl: Avoid double free_irq() for psl,slice interrupts

From: Michael Ellerman <[email-masked]>
Date: Thu, 8 Jun 2017 14:05:17 +1000 (AEST)

On Fri, 2017-06-02 at 16:56:48 UTC, Vaibhav Jain wrote:
> During an eeh call to cxl_remove can result in double free_irq of
> psl,slice interrupts. This can happen if perst_reloads_same_image == 1
> and call to cxl_configure_adapter() fails during slot_reset
> callback. In such a case we see a kernel oops with following back-trace:
> 
> Oops: Kernel access of bad area, sig: 11 [#1]
> Call Trace:
>   free_irq+0x88/0xd0 (unreliable)
>   cxl_unmap_irq+0x20/0x40 [cxl]
>   cxl_native_release_psl_irq+0x78/0xd8 [cxl]
>   pci_deconfigure_afu+0xac/0x110 [cxl]
>   cxl_remove+0x104/0x210 [cxl]
>   pci_device_remove+0x6c/0x110
>   device_release_driver_internal+0x204/0x2e0
>   pci_stop_bus_device+0xa0/0xd0
>   pci_stop_and_remove_bus_device+0x28/0x40
>   pci_hp_remove_devices+0xb0/0x150
>   pci_hp_remove_devices+0x68/0x150
>   eeh_handle_normal_event+0x140/0x580
>   eeh_handle_event+0x174/0x360
>   eeh_event_handler+0x1e8/0x1f0
> 
> This patch fixes the issue of double free_irq by checking that
> variables that hold the virqs (err_hwirq, serr_hwirq, psl_virq) are
> not '0' before un-mapping and resetting these variables to '0' when
> they are un-mapped.
> 
> Cc: [email-masked]
> Signed-off-by: Vaibhav Jain <[email-masked]>
> Reviewed-by: Andrew Donnellan <[email-masked]>
> Acked-by: Frederic Barrat <[email-masked]>

Applied to powerpc fixes, thanks.

https://git.kernel.org/powerpc/c/b3aa20ba2ba8072b73bd799605b8c9

cheers