On 02/21/2018 05:55 PM, Ram Pai wrote: > When a key is freed, the key is no more effective. > Clear the bits corresponding to the pkey in the shadow > register. Otherwise it will carry some spurious bits > which can trigger false-positive asserts. ... > diff --git a/tools/testing/selftests/vm/protection_keys.c > b/tools/testing/selftests/vm/protection_keys.c > index ca54a95..aaf9f09 100644 > --- a/tools/testing/selftests/vm/protection_keys.c > +++ b/tools/testing/selftests/vm/protection_keys.c > @@ -582,6 +582,9 @@ int alloc_pkey(void) > int sys_pkey_free(unsigned long pkey) > { > int ret = syscall(SYS_pkey_free, pkey); > + > + if (!ret) > + shadow_pkey_reg &= reset_bits(pkey, PKEY_DISABLE_ACCESS); > dprintf1("%s(pkey=%ld) syscall ret: %d\n", __func__, pkey, ret); > return ret; > }
Did this cause problems for you in practice? On x86, sys_pkey_free() does not affect PKRU, so this isn't quite right. I'd much rather have the actual tests explicitly clear the PKRU bits and also in the process clear the shadow bits.