[PATCH v3] lib/test_rhashtable: Make test_insert_dup() allocate its hash table dynamically

[Bart Van Assche]

The test_insert_dup() function from lib/test_rhashtable.c passes a
pointer to a stack object to rhltable_init(). Allocate the hash table
dynamically to avoid that the following is reported with object
debugging enabled:

ODEBUG: object (ptrval) is on stack (ptrval), but NOT annotated.
WARNING: CPU: 0 PID: 1 at lib/debugobjects.c:368 __debug_object_init+0x312/0x480
Modules linked in:
EIP: __debug_object_init+0x312/0x480
Call Trace:
 ? debug_object_init+0x1a/0x20
 ? __init_work+0x16/0x30
 ? rhashtable_init+0x1e1/0x460
 ? sched_clock_cpu+0x57/0xe0
 ? rhltable_init+0xb/0x20
 ? test_insert_dup+0x32/0x20f
 ? trace_hardirqs_on+0x38/0xf0
 ? ida_dump+0x10/0x10
 ? jhash+0x130/0x130
 ? my_hashfn+0x30/0x30
 ? test_rht_init+0x6aa/0xab4
 ? ida_dump+0x10/0x10
 ? test_rhltable+0xc5c/0xc5c
 ? do_one_initcall+0x67/0x28e
 ? trace_hardirqs_off+0x22/0xe0
 ? restore_all_kernel+0xf/0x70
 ? trace_hardirqs_on_thunk+0xc/0x10
 ? restore_all_kernel+0xf/0x70
 ? kernel_init_freeable+0x142/0x213
 ? rest_init+0x230/0x230
 ? kernel_init+0x10/0x110
 ? schedule_tail_wrapper+0x9/0xc
 ? ret_from_fork+0x19/0x24

Cc: Thomas Graf <tgraf@xxxxxxx>
Cc: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Cc: netdev@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
---

Changes compared to v2: fixed build error.

Changes compared to v1: instead of modifying rhashtable_init(), modify its
   caller.

lib/test_rhashtable.c | 23 +++++++++++++++--------
 1 file changed, 15 insertions(+), 8 deletions(-)

diff --git a/lib/test_rhashtable.c b/lib/test_rhashtable.c
index 6a8ac7626797..e52f8cafe227 100644
--- a/lib/test_rhashtable.c
+++ b/lib/test_rhashtable.c
@@ -541,38 +541,45 @@ static unsigned int __init print_ht(struct rhltable *rhlt)
 static int __init test_insert_dup(struct test_obj_rhl *rhl_test_objects,
 				  int cnt, bool slow)
 {
-	struct rhltable rhlt;
+	struct rhltable *rhlt;
 	unsigned int i, ret;
 	const char *key;
 	int err = 0;
 
-	err = rhltable_init(&rhlt, &test_rht_params_dup);
-	if (WARN_ON(err))
+	rhlt = kmalloc(sizeof(*rhlt), GFP_KERNEL);
+	if (WARN_ON(!rhlt))
+		return -EINVAL;
+
+	err = rhltable_init(rhlt, &test_rht_params_dup);
+	if (WARN_ON(err)) {
+		kfree(rhlt);
 		return err;
+	}
 
 	for (i = 0; i < cnt; i++) {
 		rhl_test_objects[i].value.tid = i;
-		key = rht_obj(&rhlt.ht, &rhl_test_objects[i].list_node.rhead);
+		key = rht_obj(&rhlt->ht, &rhl_test_objects[i].list_node.rhead);
 		key += test_rht_params_dup.key_offset;
 
 		if (slow) {
-			err = PTR_ERR(rhashtable_insert_slow(&rhlt.ht, key,
+			err = PTR_ERR(rhashtable_insert_slow(&rhlt->ht, key,
 							     &rhl_test_objects[i].list_node.rhead));
 			if (err == -EAGAIN)
 				err = 0;
 		} else
-			err = rhltable_insert(&rhlt,
+			err = rhltable_insert(rhlt,
 					      &rhl_test_objects[i].list_node,
 					      test_rht_params_dup);
 		if (WARN(err, "error %d on element %d/%d (%s)\n", err, i, cnt, slow? "slow" : "fast"))
 			goto skip_print;
 	}
 
-	ret = print_ht(&rhlt);
+	ret = print_ht(rhlt);
 	WARN(ret != cnt, "missing rhltable elements (%d != %d, %s)\n", ret, cnt, slow? "slow" : "fast");
 
 skip_print:
-	rhltable_destroy(&rhlt);
+	rhltable_destroy(rhlt);
+	kfree(rhlt);
 
 	return 0;
 }
-- 
2.20.1.495.gaa96b0ce6b-goog