Re: [PATCH] SCTP: Free the per-net sysctl table on net exit.

Neil Horman [off-list ref] writes:

On Thu, Jan 24, 2013 at 11:02:47AM -0500, Vlad Yasevich wrote:

quoted

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 <redacted>
Signed-off-by: Vlad Yasevich <redacted>
CC: "Eric W. Biederman" <redacted>
---
 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

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Acked-by: Neil Horman <nhorman@tuxdriver.com>

Reviewed-by: "Eric W. Biederman" <redacted>

Doh.  I should have known better.

Eric