Patchwork ip6gre_tunnel_xmit() leaking an skb?

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Submitter Tommi Rantala
Date Feb. 4, 2013, 12:29 p.m.
Message ID <CA+ydwtqabWALE=CtNWrDY=uiZqpHzUnami6OR-_OrK8TgNivQw@mail.gmail.com>
Download mbox | patch
Permalink /patch/217893/
State RFC
Delegated to: David Miller
Headers show

Comments

Tommi Rantala - Feb. 4, 2013, 12:29 p.m.
Hello,

kmemleak is giving me some complaints on boot:

# echo scan > /sys/kernel/debug/kmemleak
# echo scan > /sys/kernel/debug/kmemleak
[   13.084513] kmemleak: 2 new suspected memory leaks (see
/sys/kernel/debug/kmemleak)
# cat /sys/kernel/debug/kmemleak
unreferenced object 0xffff88003b4e3c00 (size 256):
  comm "dhcpcd", pid 1661, jiffies 4294670402 (age 15.097s)
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    00 00 00 00 00 00 00 00 00 80 4a 3b 00 88 ff ff  ..........J;....
  backtrace:
    [<ffffffff81b3d636>] kmemleak_alloc+0x26/0x50
    [<ffffffff81193514>] kmem_cache_alloc_node+0xb4/0x180
    [<ffffffff817c8fc0>] __alloc_skb+0x60/0x2a0
    [<ffffffff817c57c1>] sock_alloc_send_pskb+0x1d1/0x340
    [<ffffffff8190aa38>] packet_sendmsg+0xa88/0xd40
    [<ffffffff817c0b60>] sock_sendmsg+0xb0/0xe0
    [<ffffffff817c232e>] sys_sendto+0x11e/0x160
    [<ffffffff81b62859>] system_call_fastpath+0x16/0x1b
    [<ffffffffffffffff>] 0xffffffffffffffff
unreferenced object 0xffff88003af07800 (size 1024):
  comm "dhcpcd", pid 1661, jiffies 4294670402 (age 15.097s)
  hex dump (first 32 bytes):
    00 74 f0 3a 00 88 ff ff fe ed ca fe 28 00 00 00  .t.:........(...
    28 00 00 00 ad 00 00 00 f0 03 1d b7 7b cb c5 ee  (...........{...
  backtrace:
    [<ffffffff81b3d636>] kmemleak_alloc+0x26/0x50
    [<ffffffff81195ce0>] __kmalloc_node_track_caller+0xe0/0x1e0
    [<ffffffff817c8efc>] __kmalloc_reserve+0x3c/0xa0
    [<ffffffff817c8ff1>] __alloc_skb+0x91/0x2a0
    [<ffffffff817c57c1>] sock_alloc_send_pskb+0x1d1/0x340
    [<ffffffff8190aa38>] packet_sendmsg+0xa88/0xd40
    [<ffffffff817c0b60>] sock_sendmsg+0xb0/0xe0
    [<ffffffff817c232e>] sys_sendto+0x11e/0x160
    [<ffffffff81b62859>] system_call_fastpath+0x16/0x1b
    [<ffffffffffffffff>] 0xffffffffffffffff
#

Patching ip6gre_tunnel_xmit() to not return -1 fixes the kmemleak
complaint, but I have no clue if the patch is otherwise correct:

$ git diff net/ipv6/ip6_gre.c
$

Tested with v3.8-rc6.

Tommi
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Eric Dumazet - Feb. 4, 2013, 3:04 p.m.
On Mon, 2013-02-04 at 14:29 +0200, Tommi Rantala wrote:
> Hello,
> 
> kmemleak is giving me some complaints on boot:
> 
> # echo scan > /sys/kernel/debug/kmemleak
> # echo scan > /sys/kernel/debug/kmemleak
> [   13.084513] kmemleak: 2 new suspected memory leaks (see
> /sys/kernel/debug/kmemleak)
> # cat /sys/kernel/debug/kmemleak
> unreferenced object 0xffff88003b4e3c00 (size 256):
>   comm "dhcpcd", pid 1661, jiffies 4294670402 (age 15.097s)
>   hex dump (first 32 bytes):
>     00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
>     00 00 00 00 00 00 00 00 00 80 4a 3b 00 88 ff ff  ..........J;....
>   backtrace:
>     [<ffffffff81b3d636>] kmemleak_alloc+0x26/0x50
>     [<ffffffff81193514>] kmem_cache_alloc_node+0xb4/0x180
>     [<ffffffff817c8fc0>] __alloc_skb+0x60/0x2a0
>     [<ffffffff817c57c1>] sock_alloc_send_pskb+0x1d1/0x340
>     [<ffffffff8190aa38>] packet_sendmsg+0xa88/0xd40
>     [<ffffffff817c0b60>] sock_sendmsg+0xb0/0xe0
>     [<ffffffff817c232e>] sys_sendto+0x11e/0x160
>     [<ffffffff81b62859>] system_call_fastpath+0x16/0x1b
>     [<ffffffffffffffff>] 0xffffffffffffffff
> unreferenced object 0xffff88003af07800 (size 1024):
>   comm "dhcpcd", pid 1661, jiffies 4294670402 (age 15.097s)
>   hex dump (first 32 bytes):
>     00 74 f0 3a 00 88 ff ff fe ed ca fe 28 00 00 00  .t.:........(...
>     28 00 00 00 ad 00 00 00 f0 03 1d b7 7b cb c5 ee  (...........{...
>   backtrace:
>     [<ffffffff81b3d636>] kmemleak_alloc+0x26/0x50
>     [<ffffffff81195ce0>] __kmalloc_node_track_caller+0xe0/0x1e0
>     [<ffffffff817c8efc>] __kmalloc_reserve+0x3c/0xa0
>     [<ffffffff817c8ff1>] __alloc_skb+0x91/0x2a0
>     [<ffffffff817c57c1>] sock_alloc_send_pskb+0x1d1/0x340
>     [<ffffffff8190aa38>] packet_sendmsg+0xa88/0xd40
>     [<ffffffff817c0b60>] sock_sendmsg+0xb0/0xe0
>     [<ffffffff817c232e>] sys_sendto+0x11e/0x160
>     [<ffffffff81b62859>] system_call_fastpath+0x16/0x1b
>     [<ffffffffffffffff>] 0xffffffffffffffff
> #
> 
> Patching ip6gre_tunnel_xmit() to not return -1 fixes the kmemleak
> complaint, but I have no clue if the patch is otherwise correct:
> 
> $ git diff net/ipv6/ip6_gre.c
> diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
> index c727e47..131dd09 100644
> --- a/net/ipv6/ip6_gre.c
> +++ b/net/ipv6/ip6_gre.c
> @@ -960,7 +960,7 @@ static netdev_tx_t ip6gre_tunnel_xmit(struct sk_buff *skb,
>         int ret;
> 
>         if (!ip6_tnl_xmit_ctl(t))
> -               return -1;
> +               goto tx_err;
> 
>         switch (skb->protocol) {
>         case htons(ETH_P_IP):

Patch seems fine to me, please submit an official patch ;)



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Patch

diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
index c727e47..131dd09 100644
--- a/net/ipv6/ip6_gre.c
+++ b/net/ipv6/ip6_gre.c
@@ -960,7 +960,7 @@  static netdev_tx_t ip6gre_tunnel_xmit(struct sk_buff *skb,
        int ret;

        if (!ip6_tnl_xmit_ctl(t))
-               return -1;
+               goto tx_err;

        switch (skb->protocol) {
        case htons(ETH_P_IP):