Re: [PATCH v12 09/22] selftests/vm: fix alloc_random_pkey() to make it really random

From
Dave Hansen <hidden>
Date
2018-03-16 22:13:16
Also in
linux-arch, linux-kselftest, linux-mm, linuxppc-dev, lkml
On 02/21/2018 05:55 PM, Ram Pai wrote:
alloc_random_pkey() was allocating the same pkey every time.
Not all pkeys were geting tested. fixed it.
...
quoted hunk
@@ -602,13 +603,15 @@ int alloc_random_pkey(void)
 	int alloced_pkeys[NR_PKEYS];
 	int nr_alloced = 0;
 	int random_index;
+
 	memset(alloced_pkeys, 0, sizeof(alloced_pkeys));
+	srand((unsigned int)time(NULL));
 
 	/* allocate every possible key and make a note of which ones we got */
 	max_nr_pkey_allocs = NR_PKEYS;
-	max_nr_pkey_allocs = 1;
 	for (i = 0; i < max_nr_pkey_allocs; i++) {
 		int new_pkey = alloc_pkey();
The srand() is probably useful, but won't this always just do a single
alloc_pkey() now?  That seems like it will mean we always use the first
one the kernel gives us, which isn't random.
quoted hunk
-	dprintf1("%s()::%d, ret: %d pkey_reg: 0x%x shadow: 0x%x\n", __func__,
-			__LINE__, ret, __rdpkey_reg(), shadow_pkey_reg);
+	dprintf1("%s()::%d, ret: %d pkey_reg: 0x%x shadow: 0x%016lx\n",
+		__func__, __LINE__, ret, __rdpkey_reg(), shadow_pkey_reg);
 	return ret;
 }
This belonged in the pkey_reg_t patch, I think.

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Thread (1 message) 1 message, 1 author, last reply 2018-03-16
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