* [PATCH net] test_rhashtable: Add missing rcu_read_lock()
@ 2018-03-08 11:54 Paul Blakey
2018-03-08 15:58 ` Herbert Xu
0 siblings, 1 reply; 4+ messages in thread
From: Paul Blakey @ 2018-03-08 11:54 UTC (permalink / raw)
To: Thomas Graf, Herbert Xu, David Miller; +Cc: netdev, Paul Blakey
Suppress "suspicious rcu_dereference_protected() usage!" on duplicate
insertion test.
Fixes: 499ac3b60f65 ('test_rhashtable: add test case for rhl_table with duplicate objects')
Signed-off-by: Paul Blakey <paulb@mellanox.com>
---
lib/test_rhashtable.c | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)
diff --git a/lib/test_rhashtable.c b/lib/test_rhashtable.c
index f4000c1..727d3ec 100644
--- a/lib/test_rhashtable.c
+++ b/lib/test_rhashtable.c
@@ -498,14 +498,16 @@ static unsigned int __init print_ht(struct rhltable *rhlt)
char buff[512] = "";
unsigned int i, cnt = 0;
+ rcu_read_lock();
+
ht = &rhlt->ht;
- tbl = rht_dereference(ht->tbl, ht);
+ tbl = rht_dereference_rcu(ht->tbl, ht);
for (i = 0; i < tbl->size; i++) {
struct rhash_head *pos, *next;
struct test_obj_rhl *p;
- pos = rht_dereference(tbl->buckets[i], ht);
- next = !rht_is_a_nulls(pos) ? rht_dereference(pos->next, ht) : NULL;
+ pos = rht_dereference_rcu(tbl->buckets[i], ht);
+ next = !rht_is_a_nulls(pos) ? rht_dereference_rcu(pos->next, ht) : NULL;
if (!rht_is_a_nulls(pos)) {
sprintf(buff, "%s\nbucket[%d] -> ", buff, i);
@@ -516,7 +518,7 @@ static unsigned int __init print_ht(struct rhltable *rhlt)
sprintf(buff, "%s[[", buff);
do {
pos = &list->rhead;
- list = rht_dereference(list->next, ht);
+ list = rht_dereference_rcu(list->next, ht);
p = rht_obj(ht, pos);
sprintf(buff, "%s val %d (tid=%d)%s", buff, p->value.id, p->value.tid,
@@ -526,13 +528,15 @@ static unsigned int __init print_ht(struct rhltable *rhlt)
pos = next,
next = !rht_is_a_nulls(pos) ?
- rht_dereference(pos->next, ht) : NULL;
+ rht_dereference_rcu(pos->next, ht) : NULL;
sprintf(buff, "%s]]%s", buff, !rht_is_a_nulls(pos) ? " -> " : "");
}
}
printk(KERN_ERR "\n---- ht: ----%s\n-------------\n", buff);
+ rcu_read_unlock();
+
return cnt;
}
--
1.8.4.3
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH net] test_rhashtable: Add missing rcu_read_lock()
2018-03-08 11:54 [PATCH net] test_rhashtable: Add missing rcu_read_lock() Paul Blakey
@ 2018-03-08 15:58 ` Herbert Xu
2018-03-08 17:10 ` Paul Blakey
0 siblings, 1 reply; 4+ messages in thread
From: Herbert Xu @ 2018-03-08 15:58 UTC (permalink / raw)
To: Paul Blakey; +Cc: Thomas Graf, David Miller, netdev
On Thu, Mar 08, 2018 at 01:54:57PM +0200, Paul Blakey wrote:
> Suppress "suspicious rcu_dereference_protected() usage!" on duplicate
> insertion test.
>
> Fixes: 499ac3b60f65 ('test_rhashtable: add test case for rhl_table with duplicate objects')
> Signed-off-by: Paul Blakey <paulb@mellanox.com>
This shouldn't be doing a table walk in the first place.
You should convert it to using the table walk interface.
Direct table walks are forbidden because they will break when
you hit a resize.
Cheers,
--
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH net] test_rhashtable: Add missing rcu_read_lock()
2018-03-08 15:58 ` Herbert Xu
@ 2018-03-08 17:10 ` Paul Blakey
2018-03-09 15:04 ` Herbert Xu
0 siblings, 1 reply; 4+ messages in thread
From: Paul Blakey @ 2018-03-08 17:10 UTC (permalink / raw)
To: Herbert Xu; +Cc: paulb, Thomas Graf, David Miller, netdev
On 08/03/2018 17:58, Herbert Xu wrote:
> On Thu, Mar 08, 2018 at 01:54:57PM +0200, Paul Blakey wrote:
>> Suppress "suspicious rcu_dereference_protected() usage!" on duplicate
>> insertion test.
>>
>> Fixes: 499ac3b60f65 ('test_rhashtable: add test case for rhl_table with duplicate objects')
>> Signed-off-by: Paul Blakey <paulb@mellanox.com>
>
> This shouldn't be doing a table walk in the first place.
>
> You should convert it to using the table walk interface.
>
> Direct table walks are forbidden because they will break when
> you hit a resize.
>
> Cheers,
>
I know but I wanted to show the inner structure for the failure case,
iirc walk doesn't provide this.
---- ht: ----
bucket[1] -> [[ val 1 (tid=0) ]] -> [[ val 21 (tid=1) ]]
-------------
[ 3599.715501]
---- ht: ----
bucket[1] -> [[ val 1 (tid=2), val 1 (tid=0) ]] -> [[
val 21 (tid=1) ]]
-------------
[ 3599.738600]
---- ht: ----
bucket[1] -> [[ val 21 (tid=1) ]] -> [[ val 1 (tid=0) ]]
-------------
[ 3599.759443]
---- ht: ----
bucket[1] -> [[ val 21 (tid=1) ]] -> [[ val 1 (tid=2),
val 1 (tid=0) ]]
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2018-03-09 15:05 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2018-03-08 11:54 [PATCH net] test_rhashtable: Add missing rcu_read_lock() Paul Blakey
2018-03-08 15:58 ` Herbert Xu
2018-03-08 17:10 ` Paul Blakey
2018-03-09 15:04 ` Herbert Xu
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