Patchwork SCTP: Free the per-net sysctl table on net exit.

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Submitter Vlad Yasevich
Date Jan. 24, 2013, 4:02 p.m.
Message ID <1359043367-30180-1-git-send-email-vyasevich@gmail.com>
Download mbox | patch
Permalink /patch/215402/
State Changes Requested
Delegated to: David Miller
Headers show

Comments

Vlad Yasevich - Jan. 24, 2013, 4:02 p.m.
Per-net sysctl table needs to be explicitly freed at
net exit.  Otherwise we see the following with kmemleak:

unreferenced object 0xffff880402d08000 (size 2048):
  comm "chrome_sandbox", pid 18437, jiffies 4310887172 (age 9097.630s)
  hex dump (first 32 bytes):
    b2 68 89 81 ff ff ff ff 20 04 04 f8 01 88 ff ff  .h...... .......
    04 00 00 00 a4 01 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<ffffffff815b4aad>] kmemleak_alloc+0x21/0x3e
    [<ffffffff81110352>] slab_post_alloc_hook+0x28/0x2a
    [<ffffffff81113fad>] __kmalloc_track_caller+0xf1/0x104
    [<ffffffff810f10c2>] kmemdup+0x1b/0x30
    [<ffffffff81571e9f>] sctp_sysctl_net_register+0x1f/0x72
    [<ffffffff8155d305>] sctp_net_init+0x100/0x39f
    [<ffffffff814ad53c>] ops_init+0xc6/0xf5
    [<ffffffff814ad5b7>] setup_net+0x4c/0xd0
    [<ffffffff814ada5e>] copy_net_ns+0x6d/0xd6
    [<ffffffff810938b1>] create_new_namespaces+0xd7/0x147
    [<ffffffff810939f4>] copy_namespaces+0x63/0x99
    [<ffffffff81076733>] copy_process+0xa65/0x1233
    [<ffffffff81077030>] do_fork+0x10b/0x271
    [<ffffffff8100a0e9>] sys_clone+0x23/0x25
    [<ffffffff815dda73>] stub_clone+0x13/0x20
    [<ffffffffffffffff>] 0xffffffffffffffff

Reported-by: Martin Mokrejs <mmokrejs@fold.natur.cuni.cz>
Signed-off-by: Vlad Yasevich <vyasevich@gmail.com>
CC: "Eric W. Biederman" <ebiederm@xmission.com>
---
 net/sctp/sysctl.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)
Neil Horman - Jan. 24, 2013, 4:44 p.m.
On Thu, Jan 24, 2013 at 11:02:47AM -0500, Vlad Yasevich wrote:
> Per-net sysctl table needs to be explicitly freed at
> net exit.  Otherwise we see the following with kmemleak:
> 
> unreferenced object 0xffff880402d08000 (size 2048):
>   comm "chrome_sandbox", pid 18437, jiffies 4310887172 (age 9097.630s)
>   hex dump (first 32 bytes):
>     b2 68 89 81 ff ff ff ff 20 04 04 f8 01 88 ff ff  .h...... .......
>     04 00 00 00 a4 01 00 00 00 00 00 00 00 00 00 00  ................
>   backtrace:
>     [<ffffffff815b4aad>] kmemleak_alloc+0x21/0x3e
>     [<ffffffff81110352>] slab_post_alloc_hook+0x28/0x2a
>     [<ffffffff81113fad>] __kmalloc_track_caller+0xf1/0x104
>     [<ffffffff810f10c2>] kmemdup+0x1b/0x30
>     [<ffffffff81571e9f>] sctp_sysctl_net_register+0x1f/0x72
>     [<ffffffff8155d305>] sctp_net_init+0x100/0x39f
>     [<ffffffff814ad53c>] ops_init+0xc6/0xf5
>     [<ffffffff814ad5b7>] setup_net+0x4c/0xd0
>     [<ffffffff814ada5e>] copy_net_ns+0x6d/0xd6
>     [<ffffffff810938b1>] create_new_namespaces+0xd7/0x147
>     [<ffffffff810939f4>] copy_namespaces+0x63/0x99
>     [<ffffffff81076733>] copy_process+0xa65/0x1233
>     [<ffffffff81077030>] do_fork+0x10b/0x271
>     [<ffffffff8100a0e9>] sys_clone+0x23/0x25
>     [<ffffffff815dda73>] stub_clone+0x13/0x20
>     [<ffffffffffffffff>] 0xffffffffffffffff
> 
> Reported-by: Martin Mokrejs <mmokrejs@fold.natur.cuni.cz>
> Signed-off-by: Vlad Yasevich <vyasevich@gmail.com>
> CC: "Eric W. Biederman" <ebiederm@xmission.com>
> ---
>  net/sctp/sysctl.c |    4 ++++
>  1 files changed, 4 insertions(+), 0 deletions(-)
> 
> diff --git a/net/sctp/sysctl.c b/net/sctp/sysctl.c
> index 043889a..cd5712f 100644
> --- a/net/sctp/sysctl.c
> +++ b/net/sctp/sysctl.c
> @@ -366,7 +366,11 @@ int sctp_sysctl_net_register(struct net *net)
>  
>  void sctp_sysctl_net_unregister(struct net *net)
>  {
> +	struct ctl_table *table;
> +
> +	table = net->sctp.sysctl_hdr->ctl_table_arg;
>  	unregister_net_sysctl_table(net->sctp.sysctl_header);
> +	kfree(table);
>  }
>  
>  static struct ctl_table_header * sctp_sysctl_header;
> -- 
> 1.7.7.6
> 
> --
> To unsubscribe from this list: send the line "unsubscribe netdev" in
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> 
Acked-by: Neil Horman <nhorman@tuxdriver.com>

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Eric W. Biederman - Jan. 24, 2013, 10:14 p.m.
Neil Horman <nhorman@tuxdriver.com> writes:

> On Thu, Jan 24, 2013 at 11:02:47AM -0500, Vlad Yasevich wrote:
>> Per-net sysctl table needs to be explicitly freed at
>> net exit.  Otherwise we see the following with kmemleak:
>> 
>> unreferenced object 0xffff880402d08000 (size 2048):
>>   comm "chrome_sandbox", pid 18437, jiffies 4310887172 (age 9097.630s)
>>   hex dump (first 32 bytes):
>>     b2 68 89 81 ff ff ff ff 20 04 04 f8 01 88 ff ff  .h...... .......
>>     04 00 00 00 a4 01 00 00 00 00 00 00 00 00 00 00  ................
>>   backtrace:
>>     [<ffffffff815b4aad>] kmemleak_alloc+0x21/0x3e
>>     [<ffffffff81110352>] slab_post_alloc_hook+0x28/0x2a
>>     [<ffffffff81113fad>] __kmalloc_track_caller+0xf1/0x104
>>     [<ffffffff810f10c2>] kmemdup+0x1b/0x30
>>     [<ffffffff81571e9f>] sctp_sysctl_net_register+0x1f/0x72
>>     [<ffffffff8155d305>] sctp_net_init+0x100/0x39f
>>     [<ffffffff814ad53c>] ops_init+0xc6/0xf5
>>     [<ffffffff814ad5b7>] setup_net+0x4c/0xd0
>>     [<ffffffff814ada5e>] copy_net_ns+0x6d/0xd6
>>     [<ffffffff810938b1>] create_new_namespaces+0xd7/0x147
>>     [<ffffffff810939f4>] copy_namespaces+0x63/0x99
>>     [<ffffffff81076733>] copy_process+0xa65/0x1233
>>     [<ffffffff81077030>] do_fork+0x10b/0x271
>>     [<ffffffff8100a0e9>] sys_clone+0x23/0x25
>>     [<ffffffff815dda73>] stub_clone+0x13/0x20
>>     [<ffffffffffffffff>] 0xffffffffffffffff
>> 
>> Reported-by: Martin Mokrejs <mmokrejs@fold.natur.cuni.cz>
>> Signed-off-by: Vlad Yasevich <vyasevich@gmail.com>
>> CC: "Eric W. Biederman" <ebiederm@xmission.com>
>> ---
>>  net/sctp/sysctl.c |    4 ++++
>>  1 files changed, 4 insertions(+), 0 deletions(-)
>> 
>> diff --git a/net/sctp/sysctl.c b/net/sctp/sysctl.c
>> index 043889a..cd5712f 100644
>> --- a/net/sctp/sysctl.c
>> +++ b/net/sctp/sysctl.c
>> @@ -366,7 +366,11 @@ int sctp_sysctl_net_register(struct net *net)
>>  
>>  void sctp_sysctl_net_unregister(struct net *net)
>>  {
>> +	struct ctl_table *table;
>> +
>> +	table = net->sctp.sysctl_hdr->ctl_table_arg;
>>  	unregister_net_sysctl_table(net->sctp.sysctl_header);
>> +	kfree(table);
>>  }
>>  
>>  static struct ctl_table_header * sctp_sysctl_header;
>> -- 
>> 1.7.7.6
>> 
>> --
>> To unsubscribe from this list: send the line "unsubscribe netdev" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>> 
> Acked-by: Neil Horman <nhorman@tuxdriver.com>

Reviewed-by: "Eric W. Biederman" <ebiederm@xmission.com>

Doh.  I should have known better.

Eric



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David Miller - Jan. 28, 2013, 12:35 a.m.
From: Vlad Yasevich <vyasevich@gmail.com>

Date: Thu, 24 Jan 2013 11:02:47 -0500

> @@ -366,7 +366,11 @@ int sctp_sysctl_net_register(struct net *net)

>  

>  void sctp_sysctl_net_unregister(struct net *net)

>  {

> +	struct ctl_table *table;

> +

> +	table = net->sctp.sysctl_hdr->ctl_table_arg;

>  	unregister_net_sysctl_table(net->sctp.sysctl_header);

> +	kfree(table);

>  }


In what tree does this compile?  I tried both 'net' and 'net-next'
and got the same exact result:

net/sctp/sysctl.c: In function ‘sctp_sysctl_net_unregister’:
net/sctp/sysctl.c:371:19: error: ‘struct netns_sctp’ has no member named ‘sysctl_hdr’
make[1]: *** [net/sctp/sysctl.o] Error 1
make: *** [net/sctp/sysctl.o] Error 2

Patch

diff --git a/net/sctp/sysctl.c b/net/sctp/sysctl.c
index 043889a..cd5712f 100644
--- a/net/sctp/sysctl.c
+++ b/net/sctp/sysctl.c
@@ -366,7 +366,11 @@  int sctp_sysctl_net_register(struct net *net)
 
 void sctp_sysctl_net_unregister(struct net *net)
 {
+	struct ctl_table *table;
+
+	table = net->sctp.sysctl_hdr->ctl_table_arg;
 	unregister_net_sysctl_table(net->sctp.sysctl_header);
+	kfree(table);
 }
 
 static struct ctl_table_header * sctp_sysctl_header;