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.
...
quoted hunk
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.
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