[PATCH v2] powerpc/pkeys: copy pkey-tracking-information at fork()

[Michael Ellerman]

Ram Pai <linuxram at us.ibm.com> writes:

> Pkey tracking information is not copied over to the mm_struct of the
> child during fork(). This can cause the child to erroneously allocate
> keys that were already allocated. Any allocated execute-only key is lost
> aswell.
>     
> Add code; called by dup_mmap(), to copy the pkey state from parent to
> child explicitly.
>     
> This problem was originally found by Dave Hansen on x86, which turns out
> to be a problem on powerpc aswell.
>     
> Reviewed-by: Thiago Jung Bauermann <bauerman at linux.ibm.com>
> Signed-off-by: Ram Pai <linuxram at us.ibm.com>
>     
> v2: do not copy if pkeys is disabled.
>     	-- comment by Michael Ellermen

Thanks.

I changed the subject to:

  powerpc/pkeys: Fix handling of pkey state across fork()

And added tags:

  Fixes: cf43d3b26452 ("powerpc: Enable pkey subsystem")
  Cc: stable at vger.kernel.org # v4.16+

cheers