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

[Andrew Donnellan]

On 03/06/17 02:56, 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: stable at vger.kernel.org
> Signed-off-by: Vaibhav Jain <vaibhav at linux.vnet.ibm.com>

v2 change looks good to me

Reviewed-by: Andrew Donnellan <andrew.donnellan at au1.ibm.com>

-- 
Andrew Donnellan              OzLabs, ADL Canberra
andrew.donnellan at au1.ibm.com  IBM Australia Limited