* [PATCH net-next] ipv4: Fix refcount warning for new fib_info
@ 2021-08-02 16:02 David Ahern
2021-08-02 17:58 ` Matthieu Baerts
0 siblings, 1 reply; 5+ messages in thread
From: David Ahern @ 2021-08-02 16:02 UTC (permalink / raw)
To: netdev, kuba, davem; +Cc: ciorneiioana, David Ahern, Yajun Deng
Ioana reported a refcount warning when booting over NFS:
[ 5.042532] ------------[ cut here ]------------
[ 5.047184] refcount_t: addition on 0; use-after-free.
[ 5.052324] WARNING: CPU: 7 PID: 1 at lib/refcount.c:25 refcount_warn_saturate+0xa4/0x150
...
[ 5.167201] Call trace:
[ 5.169635] refcount_warn_saturate+0xa4/0x150
[ 5.174067] fib_create_info+0xc00/0xc90
[ 5.177982] fib_table_insert+0x8c/0x620
[ 5.181893] fib_magic.isra.0+0x110/0x11c
[ 5.185891] fib_add_ifaddr+0xb8/0x190
[ 5.189629] fib_inetaddr_event+0x8c/0x140
fib_treeref needs to be set after kzalloc. The old code had a ++ which
led to the confusion when the int was replaced by a refcount_t.
Fixes: 79976892f7ea ("net: convert fib_treeref from int to refcount_t")
Signed-off-by: David Ahern <dsahern@kernel.org>
Reported-by: Ioana Ciornei <ciorneiioana@gmail.com>
Cc: Yajun Deng <yajun.deng@linux.dev>
---
net/ipv4/fib_semantics.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c
index fa19f4cdf3a4..f29feb7772da 100644
--- a/net/ipv4/fib_semantics.c
+++ b/net/ipv4/fib_semantics.c
@@ -1551,7 +1551,7 @@ struct fib_info *fib_create_info(struct fib_config *cfg,
return ofi;
}
- refcount_inc(&fi->fib_treeref);
+ refcount_set(&fi->fib_treeref, 1);
refcount_set(&fi->fib_clntref, 1);
spin_lock_bh(&fib_info_lock);
hlist_add_head(&fi->fib_hash,
--
2.24.3 (Apple Git-128)
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH net-next] ipv4: Fix refcount warning for new fib_info
2021-08-02 16:02 [PATCH net-next] ipv4: Fix refcount warning for new fib_info David Ahern
@ 2021-08-02 17:58 ` Matthieu Baerts
2021-08-02 18:04 ` David Ahern
0 siblings, 1 reply; 5+ messages in thread
From: Matthieu Baerts @ 2021-08-02 17:58 UTC (permalink / raw)
To: David Ahern; +Cc: ciorneiioana, Yajun Deng, netdev, davem, kuba
Hi David,
On 02/08/2021 18:02, David Ahern wrote:
> Ioana reported a refcount warning when booting over NFS:
>
> [ 5.042532] ------------[ cut here ]------------
> [ 5.047184] refcount_t: addition on 0; use-after-free.
> [ 5.052324] WARNING: CPU: 7 PID: 1 at lib/refcount.c:25 refcount_warn_saturate+0xa4/0x150
> ...
> [ 5.167201] Call trace:
> [ 5.169635] refcount_warn_saturate+0xa4/0x150
> [ 5.174067] fib_create_info+0xc00/0xc90
> [ 5.177982] fib_table_insert+0x8c/0x620
> [ 5.181893] fib_magic.isra.0+0x110/0x11c
> [ 5.185891] fib_add_ifaddr+0xb8/0x190
> [ 5.189629] fib_inetaddr_event+0x8c/0x140
>
> fib_treeref needs to be set after kzalloc. The old code had a ++ which
> led to the confusion when the int was replaced by a refcount_t.
Thank you for the patch!
My CI was also complaining of not being able to run kernel selftests [1].
Your patch fixes the issue, thanks!
Tested-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Cheers,
Matt
[1] https://cirrus-ci.com/task/5688032394215424
--
Tessares | Belgium | Hybrid Access Solutions
www.tessares.net
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH net-next] ipv4: Fix refcount warning for new fib_info
2021-08-02 17:58 ` Matthieu Baerts
@ 2021-08-02 18:04 ` David Ahern
2021-08-02 20:20 ` Jakub Kicinski
2021-08-03 7:39 ` yajun.deng
0 siblings, 2 replies; 5+ messages in thread
From: David Ahern @ 2021-08-02 18:04 UTC (permalink / raw)
To: Matthieu Baerts, David Ahern
Cc: ciorneiioana, Yajun Deng, netdev, davem, kuba
On 8/2/21 11:58 AM, Matthieu Baerts wrote:
> Hi David,
>
> On 02/08/2021 18:02, David Ahern wrote:
>> Ioana reported a refcount warning when booting over NFS:
>>
>> [ 5.042532] ------------[ cut here ]------------
>> [ 5.047184] refcount_t: addition on 0; use-after-free.
>> [ 5.052324] WARNING: CPU: 7 PID: 1 at lib/refcount.c:25 refcount_warn_saturate+0xa4/0x150
>> ...
>> [ 5.167201] Call trace:
>> [ 5.169635] refcount_warn_saturate+0xa4/0x150
>> [ 5.174067] fib_create_info+0xc00/0xc90
>> [ 5.177982] fib_table_insert+0x8c/0x620
>> [ 5.181893] fib_magic.isra.0+0x110/0x11c
>> [ 5.185891] fib_add_ifaddr+0xb8/0x190
>> [ 5.189629] fib_inetaddr_event+0x8c/0x140
>>
>> fib_treeref needs to be set after kzalloc. The old code had a ++ which
>> led to the confusion when the int was replaced by a refcount_t.
>
> Thank you for the patch!
>
> My CI was also complaining of not being able to run kernel selftests [1].
> Your patch fixes the issue, thanks!
>
> Tested-by: Matthieu Baerts <matthieu.baerts@tessares.net>
>
Given how easily it is to trigger the warning, I get the impression the
original was an untested patch.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH net-next] ipv4: Fix refcount warning for new fib_info
2021-08-02 18:04 ` David Ahern
@ 2021-08-02 20:20 ` Jakub Kicinski
2021-08-03 7:39 ` yajun.deng
1 sibling, 0 replies; 5+ messages in thread
From: Jakub Kicinski @ 2021-08-02 20:20 UTC (permalink / raw)
To: David Ahern
Cc: Matthieu Baerts, David Ahern, ciorneiioana, Yajun Deng, netdev, davem
On Mon, 2 Aug 2021 12:04:01 -0600 David Ahern wrote:
> On 8/2/21 11:58 AM, Matthieu Baerts wrote:
> > Hi David,
> >
> > On 02/08/2021 18:02, David Ahern wrote:
> >> Ioana reported a refcount warning when booting over NFS:
> >>
> >> [ 5.042532] ------------[ cut here ]------------
> >> [ 5.047184] refcount_t: addition on 0; use-after-free.
> >> [ 5.052324] WARNING: CPU: 7 PID: 1 at lib/refcount.c:25 refcount_warn_saturate+0xa4/0x150
> >> ...
> >> [ 5.167201] Call trace:
> >> [ 5.169635] refcount_warn_saturate+0xa4/0x150
> >> [ 5.174067] fib_create_info+0xc00/0xc90
> >> [ 5.177982] fib_table_insert+0x8c/0x620
> >> [ 5.181893] fib_magic.isra.0+0x110/0x11c
> >> [ 5.185891] fib_add_ifaddr+0xb8/0x190
> >> [ 5.189629] fib_inetaddr_event+0x8c/0x140
> >>
> >> fib_treeref needs to be set after kzalloc. The old code had a ++ which
> >> led to the confusion when the int was replaced by a refcount_t.
> >
> > Thank you for the patch!
> >
> > My CI was also complaining of not being able to run kernel selftests [1].
> > Your patch fixes the issue, thanks!
> >
> > Tested-by: Matthieu Baerts <matthieu.baerts@tessares.net>
> >
>
> Given how easily it is to trigger the warning, I get the impression the
> original was an untested patch.
Yeah :( In hindsight any refcount patch which doesn't contain a
refcount_set() is suspicious. Thanks for the quick fix, applied!
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH net-next] ipv4: Fix refcount warning for new fib_info
2021-08-02 18:04 ` David Ahern
2021-08-02 20:20 ` Jakub Kicinski
@ 2021-08-03 7:39 ` yajun.deng
1 sibling, 0 replies; 5+ messages in thread
From: yajun.deng @ 2021-08-03 7:39 UTC (permalink / raw)
To: Jakub Kicinski, David Ahern
Cc: Matthieu Baerts, David Ahern, ciorneiioana, netdev, davem
August 3, 2021 4:20 AM, "Jakub Kicinski" <kuba@kernel.org> wrote:
> On Mon, 2 Aug 2021 12:04:01 -0600 David Ahern wrote:
>
>> On 8/2/21 11:58 AM, Matthieu Baerts wrote:
>> Hi David,
>>
>> On 02/08/2021 18:02, David Ahern wrote:
>> Ioana reported a refcount warning when booting over NFS:
>>
>> [ 5.042532] ------------[ cut here ]------------
>> [ 5.047184] refcount_t: addition on 0; use-after-free.
>> [ 5.052324] WARNING: CPU: 7 PID: 1 at lib/refcount.c:25 refcount_warn_saturate+0xa4/0x150
>> ...
>> [ 5.167201] Call trace:
>> [ 5.169635] refcount_warn_saturate+0xa4/0x150
>> [ 5.174067] fib_create_info+0xc00/0xc90
>> [ 5.177982] fib_table_insert+0x8c/0x620
>> [ 5.181893] fib_magic.isra.0+0x110/0x11c
>> [ 5.185891] fib_add_ifaddr+0xb8/0x190
>> [ 5.189629] fib_inetaddr_event+0x8c/0x140
>>
>> fib_treeref needs to be set after kzalloc. The old code had a ++ which
>> led to the confusion when the int was replaced by a refcount_t.
>>
>> Thank you for the patch!
>>
>> My CI was also complaining of not being able to run kernel selftests [1].
>> Your patch fixes the issue, thanks!
>>
>> Tested-by: Matthieu Baerts <matthieu.baerts@tessares.net>
>>
>> Given how easily it is to trigger the warning, I get the impression the
>> original was an untested patch.
>
> Yeah :( In hindsight any refcount patch which doesn't contain a
> refcount_set() is suspicious. Thanks for the quick fix, applied!
Sorry for that, there is another patch needed to apply for the same reason. I just submitted it.
^ permalink raw reply [flat|nested] 5+ messages in thread
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2021-08-02 16:02 [PATCH net-next] ipv4: Fix refcount warning for new fib_info David Ahern
2021-08-02 17:58 ` Matthieu Baerts
2021-08-02 18:04 ` David Ahern
2021-08-02 20:20 ` Jakub Kicinski
2021-08-03 7:39 ` yajun.deng
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