Re: [RFC PATCH 2/6] testing/pkeys: Don't use uninitialized variable

[Sohil Mehta]

On 6/10/2022 4:35 PM, ira.we...@intel.com wrote:
diff --git a/tools/testing/selftests/vm/protection_keys.c 
b/tools/testing/selftests/vm/protection_keys.c
index d0183c381859..43e47de19c0d 100644
--- a/tools/testing/selftests/vm/protection_keys.c
+++ b/tools/testing/selftests/vm/protection_keys.c
@@ -1225,9 +1225,9 @@ void test_pkey_alloc_exhaust(int *ptr, u16 pkey)
                int new_pkey;
                dprintf1("%s() alloc loop: %d\n", __func__, i);
                new_pkey = alloc_pkey();
-               dprintf4("%s()::%d, err: %d pkey_reg: 0x%016llx"
+               dprintf4("%s()::%d, errno: %d pkey_reg: 0x%016llx"

What is errno referring to over here? There are a few things happening 
in alloc_pkey(). I guess it would show the latest error that happened. 
Does errno need to be set to 0 before the call?

Also, would it be useful to print the return value (new_pkey) from 
alloc_pkey() here?

                                " shadow: 0x%016llx\n",
-                               __func__, __LINE__, err, __read_pkey_reg(),
+                               __func__, __LINE__, errno, __read_pkey_reg(),
                                shadow_pkey_reg);
                read_pkey_reg(); /* for shadow checking */
                dprintf2("%s() errno: %d ENOSPC: %d\n", __func__, errno, 
ENOSPC);

Sohil