Re: [PATCH v2] powerpc/eeh: Avoid use after free in eeh_handle_special_event()

[Andrew Donnellan <andrew.donnellan@au1.ibm.com>]

On 10/04/17 17:11, Russell Currey wrote:
> eeh_handle_special_event() is called when an EEH event is detected but
> can't be narrowed down to a specific PE.  This function looks through
> every PE to find one in an erroneous state, then calls the regular event
> handler eeh_handle_normal_event() once it knows which PE has an error.
>
> However, if eeh_handle_normal_event() found that the PE cannot possibly
> be recovered, it will free it, rendering the passed PE stale.
> This leads to a use after free in eeh_handle_special_event() as it attempts to
> clear the "recovering" state on the PE after eeh_handle_normal_event() returns.
>
> Thus, make sure the PE is valid when attempting to clear state in
> eeh_handle_special_event().
>
> Cc: <stable@vger.kernel.org> #3.10+
> Reported-by: Alexey Kardashevskiy <aik@ozlabs.ru>
> Signed-off-by: Russell Currey <ruscur@russell.cc>

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


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