lib: test_rhashtable: fix for large entry counts
During concurrent access testing, threadfunc() concatenated thread ID
and object index to create a unique key like so:
| tdata->objs[i].value = (tdata->id << 16) | i;
This breaks if a user passes an entries parameter of 64k or higher,
since 'i' might use more than 16 bits then. Effectively, this will lead
to duplicate keys in the table.
Fix the problem by introducing a struct holding object and thread ID and
using that as key instead of a single integer type field.
Fixes: f4a3e90ba5739 ("rhashtable-test: extend to test concurrency")
Reported by: Manuel Messner <mm@skelett.io>
Signed-off-by: Phil Sutter <phil@nwl.cc>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/lib/test_rhashtable.c b/lib/test_rhashtable.c
index 64e899b..16949d2 100644
--- a/lib/test_rhashtable.c
+++ b/lib/test_rhashtable.c
@@ -56,8 +56,13 @@
module_param(enomem_retry, bool, 0);
MODULE_PARM_DESC(enomem_retry, "Retry insert even if -ENOMEM was returned (default: off)");
+struct test_obj_val {
+ int id;
+ int tid;
+};
+
struct test_obj {
- int value;
+ struct test_obj_val value;
struct rhash_head node;
};
@@ -72,7 +77,7 @@
static struct rhashtable_params test_rht_params = {
.head_offset = offsetof(struct test_obj, node),
.key_offset = offsetof(struct test_obj, value),
- .key_len = sizeof(int),
+ .key_len = sizeof(struct test_obj_val),
.hashfn = jhash,
.nulls_base = (3U << RHT_BASE_SHIFT),
};
@@ -109,24 +114,26 @@
for (i = 0; i < entries * 2; i++) {
struct test_obj *obj;
bool expected = !(i % 2);
- u32 key = i;
+ struct test_obj_val key = {
+ .id = i,
+ };
- if (array[i / 2].value == TEST_INSERT_FAIL)
+ if (array[i / 2].value.id == TEST_INSERT_FAIL)
expected = false;
obj = rhashtable_lookup_fast(ht, &key, test_rht_params);
if (expected && !obj) {
- pr_warn("Test failed: Could not find key %u\n", key);
+ pr_warn("Test failed: Could not find key %u\n", key.id);
return -ENOENT;
} else if (!expected && obj) {
pr_warn("Test failed: Unexpected entry found for key %u\n",
- key);
+ key.id);
return -EEXIST;
} else if (expected && obj) {
- if (obj->value != i) {
+ if (obj->value.id != i) {
pr_warn("Test failed: Lookup value mismatch %u!=%u\n",
- obj->value, i);
+ obj->value.id, i);
return -EINVAL;
}
}
@@ -195,7 +202,7 @@
for (i = 0; i < entries; i++) {
struct test_obj *obj = &array[i];
- obj->value = i * 2;
+ obj->value.id = i * 2;
err = insert_retry(ht, &obj->node, test_rht_params);
if (err > 0)
insert_retries += err;
@@ -218,7 +225,7 @@
for (i = 0; i < entries; i++) {
u32 key = i * 2;
- if (array[i].value != TEST_INSERT_FAIL) {
+ if (array[i].value.id != TEST_INSERT_FAIL) {
obj = rhashtable_lookup_fast(ht, &key, test_rht_params);
BUG_ON(!obj);
@@ -242,18 +249,21 @@
for (i = 0; i < entries; i++) {
struct test_obj *obj;
- int key = (tdata->id << 16) | i;
+ struct test_obj_val key = {
+ .id = i,
+ .tid = tdata->id,
+ };
obj = rhashtable_lookup_fast(&ht, &key, test_rht_params);
- if (obj && (tdata->objs[i].value == TEST_INSERT_FAIL)) {
- pr_err(" found unexpected object %d\n", key);
+ if (obj && (tdata->objs[i].value.id == TEST_INSERT_FAIL)) {
+ pr_err(" found unexpected object %d-%d\n", key.tid, key.id);
err++;
- } else if (!obj && (tdata->objs[i].value != TEST_INSERT_FAIL)) {
- pr_err(" object %d not found!\n", key);
+ } else if (!obj && (tdata->objs[i].value.id != TEST_INSERT_FAIL)) {
+ pr_err(" object %d-%d not found!\n", key.tid, key.id);
err++;
- } else if (obj && (obj->value != key)) {
- pr_err(" wrong object returned (got %d, expected %d)\n",
- obj->value, key);
+ } else if (obj && memcmp(&obj->value, &key, sizeof(key))) {
+ pr_err(" wrong object returned (got %d-%d, expected %d-%d)\n",
+ obj->value.tid, obj->value.id, key.tid, key.id);
err++;
}
@@ -272,7 +282,8 @@
pr_err(" thread[%d]: down_interruptible failed\n", tdata->id);
for (i = 0; i < entries; i++) {
- tdata->objs[i].value = (tdata->id << 16) | i;
+ tdata->objs[i].value.id = i;
+ tdata->objs[i].value.tid = tdata->id;
err = insert_retry(&ht, &tdata->objs[i].node, test_rht_params);
if (err > 0) {
insert_retries += err;
@@ -295,7 +306,7 @@
for (step = 10; step > 0; step--) {
for (i = 0; i < entries; i += step) {
- if (tdata->objs[i].value == TEST_INSERT_FAIL)
+ if (tdata->objs[i].value.id == TEST_INSERT_FAIL)
continue;
err = rhashtable_remove_fast(&ht, &tdata->objs[i].node,
test_rht_params);
@@ -304,7 +315,7 @@
tdata->id);
goto out;
}
- tdata->objs[i].value = TEST_INSERT_FAIL;
+ tdata->objs[i].value.id = TEST_INSERT_FAIL;
cond_resched();
}