Messages in this thread | | | From | Marcel Hellwig <> | Subject | AW: AW: AW: PROBLEM: Kernel Oops in UDP stack | Date | Tue, 7 Aug 2018 13:42:53 +0000 |
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>> >> Well, this driver does not use NET_IP_ALIGN reservation, meaning IP header is not 4-byte aligned. >> >> No idea why mis-alignments are okay in IP layer, but not in UDP >> >> You could try to patch it to use netdev_alloc_skb_ip_align() instead of dev_alloc_skb() > > Looks very promising! CPU runs for 3 hours and no panic so far. Let's hope it survives the weekend! *fingers crossed* The strange thing I don't understand is, why does the 3.5.7 kernel does not crash (or 4.17.12, yes I managed to run a recent kernel on our machine! \o/ )? It does not use netdev_alloc_skb_ip_align either[0][1], but one thing, that I noticed it, that there is a difference in /proc/iomem > > 3.4.113 > # cat /proc/iomem > 08000000-0801ffff : lpc-eth.0 > 31060000-31060fff : lpc-eth.0 > 40088000-4008801f : serial > [...] > > 3.5.7 > # cat /proc/iomem > 20084000-20084fff : /ahb/apb/ssp@20084000 > 2008c000-2008cfff : /ahb/apb/ssp@2008c000 > 31000000-31000fff : /ahb/dma@31000000 > 40088000-4008801f : serial > [...] > > As you notice lpc-eth.0 (or 31060000.ethernet as it's called nowadays) is not listed, so my guess it is served by DMA? > > May that the reason why it does not crash (Notice: 3.5.7 runs via device tree file)? > > So just my thought: If I would disable dma (somehow) would the error still occur in today's kernel?
I think, that it is implicitly aligned today (I think!), so that's the reason why the oops does not occur anymore.
Our machines survived the 4 days now, so we are very confident, that this solved the problem for us!
Thank you very much, you all helped us a lot!
Mit freundlichen Grüßen / With kind regards
Marcel Hellwig B. Sc. Informatik Entwickler
m-u-t GmbH Am Marienhof 2 22880 Wedel Germany
Phone: +49 4103 9308 - 474 Fax: +49 4103 9308 - 99 mhellwig@mut-group.com
www.mut-group.com
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