[v3, 1/2] powerpc/eeh: Avoid use after free in eeh_handle_special_event()

[Michael Ellerman]

On Wed, 2017-04-19 at 07:39:26 UTC, 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 at vger.kernel.org> #3.10+
> Reported-by: Alexey Kardashevskiy <aik at ozlabs.ru>
> Signed-off-by: Russell Currey <ruscur at russell.cc>
> Reviewed-by: Gavin Shan <gwshan at linux.vnet.ibm.com>

Applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/daeba2956f32f91f3493788ff6ee02

cheers