[PATCH v1] net: stmmac: Free rx_skbufs before realloc

[Shunqian Zheng]

From: ZhengShunQian 

The init_dma_desc_rings() may realloc the rx_skbuff[] when
suspend and resume. This patch free the rx_skbuff[] before
reallocing memory.

Signed-off-by: ZhengShunQian 
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 18 ++
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c 
b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 64d8aa4..2af1ed9 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -1022,6 +1022,14 @@ static void stmmac_free_rx_buffers(struct stmmac_priv 
*priv, int i)
priv->rx_skbuff[i] = NULL;
 }
 
+static void dma_free_rx_skbufs(struct stmmac_priv *priv)
+{
+   int i;
+
+   for (i = 0; i < priv->dma_rx_size; i++)
+   stmmac_free_rx_buffers(priv, i);
+}
+
 /**
  * init_dma_desc_rings - init the RX/TX descriptor rings
  * @dev: net device structure
@@ -1058,6 +1066,8 @@ static int init_dma_desc_rings(struct net_device *dev, 
gfp_t flags)
/* RX INITIALIZATION */
pr_debug("\tSKB addresses:\nskb\t\tskb data\tdma data\n");
}
+
+   dma_free_rx_skbufs(priv);
for (i = 0; i < rxsize; i++) {
struct dma_desc *p;
if (priv->extend_desc)
@@ -1122,14 +1132,6 @@ err_init_rx_buffers:
return ret;
 }
 
-static void dma_free_rx_skbufs(struct stmmac_priv *priv)
-{
-   int i;
-
-   for (i = 0; i < priv->dma_rx_size; i++)
-   stmmac_free_rx_buffers(priv, i);
-}
-
 static void dma_free_tx_skbufs(struct stmmac_priv *priv)
 {
int i;
-- 
1.9.1

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[RFC PATCH v1] Trying to fix the stmmac memory leak during suspend/resume

[Shunqian Zheng]

From: ZhengShunQian 

When I run Suspend-to-Ram stress test on my Rockchip RK3288(SoC) board
that integrated stmmac ethernet, it always OOM after a few iterations,
usually 50 times is enough to reproduce.

Compiled kernel with KMEMLEAK feature, I got the logs as below:
unreferenced object 0xed89ac00 (size 192):
  comm "busybox", pid 79, jiffies 2251 (age 54.580s)
  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 d1 ed 00 00 00 00 00 00 00 00  
  backtrace:
[] kmemleak_alloc+0x44/0x78
[] kmem_cache_alloc+0x1ac/0x264
[] __build_skb+0x38/0x9c
[] __netdev_alloc_skb+0xac/0x118
[] init_dma_desc_rings+0xcc/0x474
[] stmmac_resume+0xc4/0x14c
[] stmmac_pltfr_resume+0x3c/0x40
[] platform_pm_resume+0x3c/0x50
[] dpm_run_callback+0x7c/0x160
[] device_resume+0x174/0x1c0
[] dpm_resume+0x110/0x2cc
[] dpm_resume_end+0x1c/0x28
[] suspend_devices_and_enter+0x53c/0x6ec
[] pm_suspend+0x334/0x478
[] state_store+0xac/0xc8
[] kobj_attr_store+0x1c/0x28

Actually I don't think I know net/stmmac good enough to fix this bug.
I really appreciate that the exports of net/stmmac can take over it if
you think it is a bug too.

ZhengShunQian (1):
  net: stmmac: Free rx_skbufs before realloc

 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 18 ++
 1 file changed, 10 insertions(+), 8 deletions(-)

-- 
1.9.1

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