FAILED: patch "[PATCH] epic100: fix use after free on rmmod" failed to apply to 4.19-stable tree

The patch below does not apply to the 4.19-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 8ee9d82cd0a45e7d050ade598c9f33032a0f2891 Mon Sep 17 00:00:00 2001
From: Tong Zhang <[email protected]>
Date: Sun, 26 Jun 2022 21:33:48 -0700
Subject: [PATCH] epic100: fix use after free on rmmod

epic_close() calls epic_rx() and uses dma buffer, but in epic_remove_one() we already freed the dma buffer. To fix this issue, reorder function calls like in the .probe function.

BUG: KASAN: use-after-free in epic_rx+0xa6/0x7e0 [epic100]
Call Trace:
 epic_rx+0xa6/0x7e0 [epic100]
 epic_close+0xec/0x2f0 [epic100]
 unregister_netdev+0x18/0x20
 epic_remove_one+0xaa/0xf0 [epic100]

index a0654e88444c..0329caf63279 100644
@@ -1515,14 +1515,14 @@ static void epic_remove_one(struct pci_dev *pdev)
 	struct net_device *dev = pci_get_drvdata(pdev);
 	struct epic_private *ep = netdev_priv(dev);
 
+	unregister_netdev(dev);
 	dma_free_coherent(&pdev->dev, TX_TOTAL_SIZE, ep->tx_ring,
 			  ep->tx_ring_dma);
 	dma_free_coherent(&pdev->dev, RX_TOTAL_SIZE, ep->rx_ring,
 			  ep->rx_ring_dma);
-	unregister_netdev(dev);
 	pci_iounmap(pdev, ep->ioaddr);
-	pci_release_regions(pdev);
 	free_netdev(dev);
+	pci_release_regions(pdev);
 	pci_disable_device(pdev);
 	/* pci_power_off(pdev, -1); */
 }