From: Antoine Tenart <antoine.tenart@free-electrons.com>
Date: Tue, 28 Nov 2017 14:19:48 +0100
Subject: net: mvpp2: fix the txq_init error path
Patch-mainline: v4.15-rc2
Git-commit: ba2d8d887d962c2f790e6dc01b2fd25b4608720b
References: bsc#1098633

When an allocation in the txq_init path fails, the allocated buffers
end-up being freed twice: in the txq_init error path, and in txq_deinit.
This lead to issues as txq_deinit would work on already freed memory
regions:

    kernel BUG at mm/slub.c:3915!
    Internal error: Oops - BUG: 0 [#1] PREEMPT SMP

This patch fixes this by removing the txq_init own error path, as the
txq_deinit function is always called on errors. This was introduced by
TSO as way more buffers are allocated.

Fixes: 186cd4d4e414 ("net: mvpp2: software tso support")
Signed-off-by: Antoine Tenart <antoine.tenart@free-electrons.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/ethernet/marvell/mvpp2.c |   20 ++------------------
 1 file changed, 2 insertions(+), 18 deletions(-)

--- a/drivers/net/ethernet/marvell/mvpp2.c
+++ b/drivers/net/ethernet/marvell/mvpp2.c
@@ -5805,7 +5805,7 @@ static int mvpp2_txq_init(struct mvpp2_p
 						sizeof(*txq_pcpu->buffs),
 						GFP_KERNEL);
 		if (!txq_pcpu->buffs)
-			goto cleanup;
+			return -ENOMEM;
 
 		txq_pcpu->count = 0;
 		txq_pcpu->reserved_num = 0;
@@ -5821,26 +5821,10 @@ static int mvpp2_txq_init(struct mvpp2_p
 					   &txq_pcpu->tso_headers_dma,
 					   GFP_KERNEL);
 		if (!txq_pcpu->tso_headers)
-			goto cleanup;
+			return -ENOMEM;
 	}
 
 	return 0;
-cleanup:
-	for_each_present_cpu(cpu) {
-		txq_pcpu = per_cpu_ptr(txq->pcpu, cpu);
-		kfree(txq_pcpu->buffs);
-
-		dma_free_coherent(port->dev->dev.parent,
-				  txq_pcpu->size * TSO_HEADER_SIZE,
-				  txq_pcpu->tso_headers,
-				  txq_pcpu->tso_headers_dma);
-	}
-
-	dma_free_coherent(port->dev->dev.parent,
-			  txq->size * MVPP2_DESC_ALIGNED_SIZE,
-			  txq->descs, txq->descs_dma);
-
-	return -ENOMEM;
 }
 
 /* Free allocated TXQ resources */