linux-kernel - [PATCH] drivers: net: cpsw: fix kmemleak false-positive reports for sk buffers

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <20160809120944.23185-1-grygorii.strashko@ti.com>
Date:	Tue, 9 Aug 2016 15:09:44 +0300
From:	Grygorii Strashko <grygorii.strashko@...com>
To:	"David S. Miller" <davem@...emloft.net>, <netdev@...r.kernel.org>,
	Mugunthan V N <mugunthanvnm@...com>,
	Catalin Marinas <catalin.marinas@....com>
CC:	Sekhar Nori <nsekhar@...com>, <linux-kernel@...r.kernel.org>,
	<linux-omap@...r.kernel.org>,
	Grygorii Strashko <grygorii.strashko@...com>
Subject: [PATCH] drivers: net: cpsw: fix kmemleak false-positive reports for sk buffers

Kmemleak reports following false positive memory leaks for each sk
buffers allocated by CPSW (__netdev_alloc_skb_ip_align()) in
cpsw_ndo_open() and cpsw_rx_handler():

unreferenced object 0xea915000 (size 2048):
  comm "systemd-network", pid 713, jiffies 4294938323 (age 102.180s)
  hex dump (first 32 bytes):
    00 58 91 ea ff ff ff ff ff ff ff ff ff ff ff ff  .X..............
    ff ff ff ff ff ff fd 0f 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<c0108680>] __kmalloc_track_caller+0x1a4/0x230
    [<c0529eb4>] __alloc_skb+0x68/0x16c
    [<c052c884>] __netdev_alloc_skb+0x40/0x104
    [<bf1ad29c>] cpsw_ndo_open+0x374/0x670 [ti_cpsw]
    [<c053c3d4>] __dev_open+0xb0/0x114
    [<c053c690>] __dev_change_flags+0x9c/0x14c
    [<c053c760>] dev_change_flags+0x20/0x50
    [<c054bdcc>] do_setlink+0x2cc/0x78c
    [<c054c358>] rtnl_setlink+0xcc/0x100
    [<c054b34c>] rtnetlink_rcv_msg+0x184/0x224
    [<c056467c>] netlink_rcv_skb+0xa8/0xc4
    [<c054b1c0>] rtnetlink_rcv+0x2c/0x34
    [<c0564018>] netlink_unicast+0x16c/0x1f8
    [<c0564498>] netlink_sendmsg+0x334/0x348
    [<c052015c>] sock_sendmsg+0x1c/0x2c
    [<c05213e0>] SyS_sendto+0xc0/0xe8

unreferenced object 0xec861780 (size 192):
  comm "softirq", pid 0, jiffies 4294938759 (age 109.540s)
  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 b0 5a ed 00 00 00 00 00 00 00 00  ......Z.........
  backtrace:
    [<c0107830>] kmem_cache_alloc+0x190/0x208
    [<c052c768>] __build_skb+0x30/0x98
    [<c052c8fc>] __netdev_alloc_skb+0xb8/0x104
    [<bf1abc54>] cpsw_rx_handler+0x68/0x1e4 [ti_cpsw]
    [<bf11aa30>] __cpdma_chan_free+0xa8/0xc4 [davinci_cpdma]
    [<bf11ab98>] __cpdma_chan_process+0x14c/0x16c [davinci_cpdma]
    [<bf11abfc>] cpdma_chan_process+0x44/0x5c [davinci_cpdma]
    [<bf1adc78>] cpsw_rx_poll+0x1c/0x9c [ti_cpsw]
    [<c0539180>] net_rx_action+0x1f0/0x2ec
    [<c003881c>] __do_softirq+0x134/0x258
    [<c0038a00>] do_softirq+0x68/0x70
    [<c0038adc>] __local_bh_enable_ip+0xd4/0xe8
    [<c0640994>] _raw_spin_unlock_bh+0x30/0x34
    [<c05f4e9c>] igmp6_group_added+0x4c/0x1bc
    [<c05f6600>] ipv6_dev_mc_inc+0x398/0x434
    [<c05dba74>] addrconf_dad_work+0x224/0x39c

This happens because CPSW allocates SK buffers and then passes
pointers on them in CPDMA where they stored in internal CPPI RAM
(SRAM) which belongs to DEV MMIO space. Kmemleak does not scan IO
memory and so reports memory leaks.

Hence, mark allocated sk buffers as false positive explicitly.

Cc: Catalin Marinas <catalin.marinas@....com>
Signed-off-by: Grygorii Strashko <grygorii.strashko@...com>
---
 drivers/net/ethernet/ti/cpsw.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/net/ethernet/ti/cpsw.c b/drivers/net/ethernet/ti/cpsw.c
index 0805855..0456e0e 100644
--- a/drivers/net/ethernet/ti/cpsw.c
+++ b/drivers/net/ethernet/ti/cpsw.c
@@ -732,6 +732,7 @@ static void cpsw_rx_handler(void *token, int len, int status)
 		netif_receive_skb(skb);
 		ndev->stats.rx_bytes += len;
 		ndev->stats.rx_packets++;
+		kmemleak_not_leak(new_skb);
 	} else {
 		ndev->stats.rx_dropped++;
 		new_skb = skb;
@@ -1323,6 +1324,7 @@ static int cpsw_ndo_open(struct net_device *ndev)
 				kfree_skb(skb);
 				goto err_cleanup;
 			}
+			kmemleak_not_leak(skb);
 		}
 		/* continue even if we didn't manage to submit all
 		 * receive descs
-- 
2.9.2