[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] Bug in Linux dom0 netback?
Hello, We are wondering whether someone can confirm that there is a bug in the netback driver in dom0 Linux - that shows up in Xen 3.2. We cannot create a domU that uses networking - as soon as we try dom0 reboots after a crash in net_rx_action. In netbk_gop_frag we find the following code: if (!xen_feature(XENFEAT_auto_translated_physmap)) { new_mfn = alloc_mfn(); /* * Set the new P2M table entry before * reassigning the old data page. Heed the * comment in pgtable-2level.h:pte_page(). :-) */ set_phys_to_machine(page_to_pfn(page), new_mfn); mcl = npo->mcl + npo->mcl_prod++; Notice !xen_feature(XENFEAT_auto_translated_physmap) and npo->mcl_prod++ Now in net_rx_action we find the following code if (npo.mcl_prod) { BUG_ON(!xen_feature(XENFEAT_auto_translated_physmap)); As far as I can tell mcl_prod is only increased in netbk_gop_frag and only if the auto_translated_physmap feature is not available. However, in net_rx_action we will crash if the auto_translated_physmap feature is not available - hence - if auto_translated_physmap is not available netback always crashes. We are not using HVM. In Xen 3.1 the code in net_rx_action looked like this: if (npo.mcl_prod && !xen_feature(XENFEAT_auto_translated_physmap)) It seems like someone wanted to avoid the check in the if-statement and turned it into a BUG_ON statement inside the if instead - but forgot to invert the condition. Can anyone confirm? Best Regards, Joakim Dahlstedt Notice: This email message, together with any attachments, may contain information of BEA Systems, Inc., its subsidiaries and affiliated entities, that may be confidential, proprietary, copyrighted and/or legally privileged, and is intended solely for the use of the individual or entity named in this message. If you are not the intended recipient, and have received this message in error, please immediately return this by email and then delete it. _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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