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[3/4] net: ll_temac: Fix TX BD buffer overwrite

Message ID af756a6fda027c300f38f73cad133450f7dd1636.1624013456.git.esben@geanix.com (mailing list archive)
State Accepted
Commit c364df2489b8ef2f5e3159b1dff1ff1fdb16040d
Delegated to: Netdev Maintainers
Headers show
Series [1/4] net: ll_temac: Make sure to free skb when it is completely used | expand

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netdev/module_param success Was 0 now: 0
netdev/build_32bit success Errors and warnings before: 29 this patch: 29
netdev/kdoc success Errors and warnings before: 0 this patch: 0
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netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 8 lines checked
netdev/build_allmodconfig_warn success Errors and warnings before: 29 this patch: 29
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Commit Message

Esben Haabendal June 18, 2021, 10:52 a.m. UTC
Just as the initial check, we need to ensure num_frag+1 buffers available,
as that is the number of buffers we are going to use.

This fixes a buffer overflow, which might be seen during heavy network
load. Complete lockup of TEMAC was reproducible within about 10 minutes of
a particular load.

Fixes: 84823ff80f74 ("net: ll_temac: Fix race condition causing TX hang")
Cc: stable@vger.kernel.org # v5.4+
Signed-off-by: Esben Haabendal <esben@geanix.com>
---
 drivers/net/ethernet/xilinx/ll_temac_main.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
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Patch

diff --git a/drivers/net/ethernet/xilinx/ll_temac_main.c b/drivers/net/ethernet/xilinx/ll_temac_main.c
index 9797aa3221d1..cc482ee36501 100644
--- a/drivers/net/ethernet/xilinx/ll_temac_main.c
+++ b/drivers/net/ethernet/xilinx/ll_temac_main.c
@@ -861,7 +861,7 @@  temac_start_xmit(struct sk_buff *skb, struct net_device *ndev)
 		smp_mb();
 
 		/* Space might have just been freed - check again */
-		if (temac_check_tx_bd_space(lp, num_frag))
+		if (temac_check_tx_bd_space(lp, num_frag + 1))
 			return NETDEV_TX_BUSY;
 
 		netif_wake_queue(ndev);