Re: net: memory leak due to CLONE_NEWNET

[Dmitry Vyukov]

On Sun, Apr 3, 2016 at 12:31 AM, Cong Wang  wrote:
> On Sat, Apr 2, 2016 at 6:55 AM, Dmitry Vyukov  wrote:
>> Hello,
>>
>> The following program leads to memory leaks in:
>>
>> unreferenced object 0x88005c10d208 (size 96):
>>   comm "a.out", pid 10753, jiffies 4296778619 (age 43.118s)
>>   hex dump (first 32 bytes):
>> e8 31 85 2d 00 88 ff ff 0f 00 00 00 00 00 00 00  .1.-
>> 00 00 00 00 ad 4e ad de ff ff ff ff 00 00 00 00  .N..
>>   backtrace:
>> [] kmemleak_alloc+0x63/0xa0 mm/kmemleak.c:915
>> [< inline >] kmemleak_alloc_recursive include/linux/kmemleak.h:47
>> [< inline >] slab_post_alloc_hook mm/slab.h:406
>> [< inline >] slab_alloc_node mm/slub.c:2602
>> [< inline >] slab_alloc mm/slub.c:2610
>> [] kmem_cache_alloc_trace+0x160/0x3d0 mm/slub.c:2627
>> [< inline >] kmalloc include/linux/slab.h:478
>> [< inline >] tc_action_net_init include/net/act_api.h:122
>> [] csum_init_net+0x15e/0x450 net/sched/act_csum.c:593
>> [] ops_init+0xa9/0x3a0 net/core/net_namespace.c:109
>> [] setup_net+0x1b4/0x3e0 net/core/net_namespace.c:287
>> [] copy_net_ns+0xd6/0x1a0 net/core/net_namespace.c:367
>> [] create_new_namespaces+0x37f/0x740 
>> kernel/nsproxy.c:106
>> [] unshare_nsproxy_namespaces+0xa9/0x1d0
>
> The following patch should fix it.
>
> diff --git a/include/net/act_api.h b/include/net/act_api.h
> index 2a19fe1..03e322b 100644
> --- a/include/net/act_api.h
> +++ b/include/net/act_api.h
> @@ -135,6 +135,7 @@ void tcf_hashinfo_destroy(const struct tc_action_ops *ops,
>  static inline void tc_action_net_exit(struct tc_action_net *tn)
>  {
> tcf_hashinfo_destroy(tn->ops, tn->hinfo);
> +   kfree(tn->hinfo);
>  }
>
>  int tcf_generic_walker(struct tc_action_net *tn, struct sk_buff *skb,


Fixes the leak for me.

Tested-by: Dmitry Vyukov 

Thanks

Re: net: memory leak due to CLONE_NEWNET

[Cong Wang]

On Sat, Apr 2, 2016 at 6:55 AM, Dmitry Vyukov  wrote:
> Hello,
>
> The following program leads to memory leaks in:
>
> unreferenced object 0x88005c10d208 (size 96):
>   comm "a.out", pid 10753, jiffies 4296778619 (age 43.118s)
>   hex dump (first 32 bytes):
> e8 31 85 2d 00 88 ff ff 0f 00 00 00 00 00 00 00  .1.-
> 00 00 00 00 ad 4e ad de ff ff ff ff 00 00 00 00  .N..
>   backtrace:
> [] kmemleak_alloc+0x63/0xa0 mm/kmemleak.c:915
> [< inline >] kmemleak_alloc_recursive include/linux/kmemleak.h:47
> [< inline >] slab_post_alloc_hook mm/slab.h:406
> [< inline >] slab_alloc_node mm/slub.c:2602
> [< inline >] slab_alloc mm/slub.c:2610
> [] kmem_cache_alloc_trace+0x160/0x3d0 mm/slub.c:2627
> [< inline >] kmalloc include/linux/slab.h:478
> [< inline >] tc_action_net_init include/net/act_api.h:122
> [] csum_init_net+0x15e/0x450 net/sched/act_csum.c:593
> [] ops_init+0xa9/0x3a0 net/core/net_namespace.c:109
> [] setup_net+0x1b4/0x3e0 net/core/net_namespace.c:287
> [] copy_net_ns+0xd6/0x1a0 net/core/net_namespace.c:367
> [] create_new_namespaces+0x37f/0x740 
> kernel/nsproxy.c:106
> [] unshare_nsproxy_namespaces+0xa9/0x1d0

The following patch should fix it.

diff --git a/include/net/act_api.h b/include/net/act_api.h
index 2a19fe1..03e322b 100644
--- a/include/net/act_api.h
+++ b/include/net/act_api.h
@@ -135,6 +135,7 @@ void tcf_hashinfo_destroy(const struct tc_action_ops *ops,
 static inline void tc_action_net_exit(struct tc_action_net *tn)
 {
tcf_hashinfo_destroy(tn->ops, tn->hinfo);
+   kfree(tn->hinfo);
 }

 int tcf_generic_walker(struct tc_action_net *tn, struct sk_buff *skb,

net: memory leak due to CLONE_NEWNET

[Dmitry Vyukov]

Hello,

The following program leads to memory leaks in:

unreferenced object 0x88005c10d208 (size 96):
  comm "a.out", pid 10753, jiffies 4296778619 (age 43.118s)
  hex dump (first 32 bytes):
e8 31 85 2d 00 88 ff ff 0f 00 00 00 00 00 00 00  .1.-
00 00 00 00 ad 4e ad de ff ff ff ff 00 00 00 00  .N..
  backtrace:
[] kmemleak_alloc+0x63/0xa0 mm/kmemleak.c:915
[< inline >] kmemleak_alloc_recursive include/linux/kmemleak.h:47
[< inline >] slab_post_alloc_hook mm/slab.h:406
[< inline >] slab_alloc_node mm/slub.c:2602
[< inline >] slab_alloc mm/slub.c:2610
[] kmem_cache_alloc_trace+0x160/0x3d0 mm/slub.c:2627
[< inline >] kmalloc include/linux/slab.h:478
[< inline >] tc_action_net_init include/net/act_api.h:122
[] csum_init_net+0x15e/0x450 net/sched/act_csum.c:593
[] ops_init+0xa9/0x3a0 net/core/net_namespace.c:109
[] setup_net+0x1b4/0x3e0 net/core/net_namespace.c:287
[] copy_net_ns+0xd6/0x1a0 net/core/net_namespace.c:367
[] create_new_namespaces+0x37f/0x740 kernel/nsproxy.c:106
[] unshare_nsproxy_namespaces+0xa9/0x1d0
kernel/nsproxy.c:205
[< inline >] SYSC_unshare kernel/fork.c:2019
[] SyS_unshare+0x3b3/0x800 kernel/fork.c:1969
[] entry_SYSCALL_64_fastpath+0x23/0xc1
arch/x86/entry/entry_64.S:207
[] 0x
unreferenced object 0x88005c10e1c8 (size 96):
  comm "a.out", pid 10753, jiffies 4296778620 (age 43.117s)
  hex dump (first 32 bytes):
e8 0b 85 2d 00 88 ff ff 0f 00 00 00 00 00 ad de  ...-
00 00 00 00 ad 4e ad de ff ff ff ff 00 00 00 00  .N..
  backtrace:
[] kmemleak_alloc+0x63/0xa0 mm/kmemleak.c:915
[< inline >] kmemleak_alloc_recursive include/linux/kmemleak.h:47
[< inline >] slab_post_alloc_hook mm/slab.h:406
[< inline >] slab_alloc_node mm/slub.c:2602
[< inline >] slab_alloc mm/slub.c:2610
[] kmem_cache_alloc_trace+0x160/0x3d0 mm/slub.c:2627
[< inline >] kmalloc include/linux/slab.h:478
[< inline >] tc_action_net_init include/net/act_api.h:122
[] ife_init_net+0x15e/0x450 net/sched/act_ife.c:838
[] ops_init+0xa9/0x3a0 net/core/net_namespace.c:109
[] setup_net+0x1b4/0x3e0 net/core/net_namespace.c:287
[] copy_net_ns+0xd6/0x1a0 net/core/net_namespace.c:367
[] create_new_namespaces+0x37f/0x740 kernel/nsproxy.c:106
[] unshare_nsproxy_namespaces+0xa9/0x1d0
kernel/nsproxy.c:205
[< inline >] SYSC_unshare kernel/fork.c:2019
[] SyS_unshare+0x3b3/0x800 kernel/fork.c:1969
[] entry_SYSCALL_64_fastpath+0x23/0xc1
arch/x86/entry/entry_64.S:207
[] 0x
unreferenced object 0x880025a55b08 (size 96):
  comm "a.out", pid 10702, jiffies 4296768144 (age 61.526s)
  hex dump (first 32 bytes):
28 ed 55 2b 00 88 ff ff 0f 00 00 00 00 00 00 00  (.U+
00 00 00 00 ad 4e ad de ff ff ff ff 00 00 00 00  .N..
  backtrace:
[] kmemleak_alloc+0x63/0xa0 mm/kmemleak.c:915
[< inline >] kmemleak_alloc_recursive include/linux/kmemleak.h:47
[< inline >] slab_post_alloc_hook mm/slab.h:406
[< inline >] slab_alloc_node mm/slub.c:2602
[< inline >] slab_alloc mm/slub.c:2610
[] kmem_cache_alloc_trace+0x160/0x3d0 mm/slub.c:2627
[< inline >] kmalloc include/linux/slab.h:478
[< inline >] tc_action_net_init include/net/act_api.h:122
[] nat_init_net+0x15e/0x450 net/sched/act_nat.c:311
[] ops_init+0xa9/0x3a0 net/core/net_namespace.c:109
[] setup_net+0x1b4/0x3e0 net/core/net_namespace.c:287
[] copy_net_ns+0xd6/0x1a0 net/core/net_namespace.c:367
[] create_new_namespaces+0x37f/0x740 kernel/nsproxy.c:106
[] unshare_nsproxy_namespaces+0xa9/0x1d0
kernel/nsproxy.c:205
[< inline >] SYSC_unshare kernel/fork.c:2019
[] SyS_unshare+0x3b3/0x800 kernel/fork.c:1969
[] entry_SYSCALL_64_fastpath+0x23/0xc1
arch/x86/entry/entry_64.S:207
[] 0x


#include 
#include 
#include 
#include 
#include 
#include 

int main()
{
int pid, status;

pid = fork();
if (pid == 0) {
unshare(CLONE_NEWNET);
exit(0);
}
while (waitpid(pid, , 0) != pid) {
}
return 0;
}


grep "kmalloc-96" /proc/slabinfo confirms the leak.

I am on commit 05cf8077e54b20dddb756eaa26f3aeb5c38dd3cf (Apr 1).