[Xen-users] warning trace while starting domU

[Shriganesh Shintre <shriganeshs@xxxxxxxxx>]

Environment: Xen 4.1.1 with Linux 3.0.4 kernel (compiled with DEBUG enabled)

I am chasing the warning trace while starting domU. Trace is as follows

Sep 12 22:18:58 ucs-xen24-srv1 kernel: ------------[ cut here ]------------
Sep 12 22:18:58 ucs-xen24-srv1 kernel: WARNING: at arch/x86/xen/mmu.c:486 xen_make_pte_debug+0xdb/0x187()
Sep 12 22:18:58 ucs-xen24-srv1 kernel: Hardware name: N20-B6625-1
Sep 12 22:18:58 ucs-xen24-srv1 kernel: 0xec0f1000 is using VM_IO, but it is 0xfffff000!
Sep 12 22:18:58 ucs-xen24-srv1 kernel: Modules linked in: veth raid1 vnp iptable_filter ip_tables bridge stp ipmi_si ipmi_devintf ipmi_msghandler nbd hoop bonding xt_tcpudp x_tables ipv6 xenfs loop dm_mirror dm_region_hash dm_log dm_multipath scsi_dh dm_mod thermal fan parport nvram sg ub enic acpi_power_meter hwmon 8250_pnp button 8250 i2c_i801 ehci_hcd serial_core ioatdma i2c_core iTCO_wdt iTCO_vendor_support uhci_hcd dca pcspkr mptsas mptscsih mptbase scsi_transport_sas sd_mod scsi_mod ext3 jbd mbcache [last unloaded: ip_tables]
Sep 12 22:18:58 ucs-xen24-srv1 kernel: Pid: 16534, comm: xend Tainted: G        W   3.0.1-11.xen0 #1
Sep 12 22:18:58 ucs-xen24-srv1 kernel: Call Trace:
Sep 12 22:18:58 ucs-xen24-srv1 kernel:  [<c100647f>] ? xen_make_pte_debug+0xdb/0x187
Sep 12 22:18:58 ucs-xen24-srv1 kernel:  [<c10351e0>] warn_slowpath_common+0x76/0x8b
Sep 12 22:18:58 ucs-xen24-srv1 kernel:  [<c100647f>] ? xen_make_pte_debug+0xdb/0x187
Sep 12 22:18:58 ucs-xen24-srv1 kernel:  [<c1035271>] warn_slowpath_fmt+0x2e/0x30
Sep 12 22:18:58 ucs-xen24-srv1 kernel:  [<c100647f>] xen_make_pte_debug+0xdb/0x187
Sep 12 22:18:58 ucs-xen24-srv1 kernel:  [<c100466e>] __raw_callee_save_xen_make_pte_debug+0x6/0x8
Sep 12 22:18:59 ucs-xen24-srv1 kernel:  [<c1004db9>] ? remap_area_mfn_pte_fn+0x60/0xf7
Sep 12 22:18:59 ucs-xen24-srv1 kernel:  [<c10842b9>] apply_to_page_range+0x1fe/0x307
Sep 12 22:18:59 ucs-xen24-srv1 kernel:  [<c100514c>] xen_remap_domain_mfn_range+0xd3/0x107
Sep 12 22:18:59 ucs-xen24-srv1 logger: /etc/xen/scripts/block: add XENBUS_PATH=backend/vbd/1/768
Sep 12 22:18:59 ucs-xen24-srv1 logger: /etc/xen/scripts/block: add XENBUS_PATH=backend/vbd/1/832
Sep 12 22:18:59 ucs-xen24-srv1 kernel:  [<c1004d59>] ? xen_make_pte+0x113/0x113
Sep 12 22:18:59 ucs-xen24-srv1 logger: /etc/xen/scripts/block: add XENBUS_PATH=backend/vbd/1/5632
Sep 12 22:18:59 ucs-xen24-srv1 logger: /etc/xen/scripts/block: add XENBUS_PATH=backend/vbd/1/5696
Sep 12 22:18:59 ucs-xen24-srv1 VRM: TP_SKT.c(1193): m_skt_connect(): Failed to connect to remote host, err=No route to host, 113
Sep 12 22:18:59 ucs-xen24-srv1 kernel:  [<c1007097>] ? xen_restore_fl_direct_reloc+0x4/0x4
Sep 12 22:19:00 ucs-xen24-srv1 kernel:  [<c1005352>] ? xen_flush_tlb+0x5f/0x6c
Sep 12 22:19:00 ucs-xen24-srv1 kernel:  [<c1024766>] ? kernel_map_pages+0xab/0x104
Sep 12 22:19:00 ucs-xen24-srv1 kernel:  [<c107288d>] ? get_page_from_freelist+0x255/0x39c
Sep 12 22:19:00 ucs-xen24-srv1 kernel:  [<c10044a5>] ? xen_mc_flush+0x101/0x1b6
Sep 12 22:19:00 ucs-xen24-srv1 kernel:  [<c1072b9e>] ? __alloc_pages_nodemask+0xd9/0x561
Sep 12 22:19:00 ucs-xen24-srv1 kernel:  [<c10823eb>] ? do_wp_page+0x348/0x879
Sep 12 22:19:00 ucs-xen24-srv1 kernel:  [<f818909b>] mmap_batch_fn+0x3c/0x5b [xenfs]
Sep 12 22:19:00 ucs-xen24-srv1 kernel:  [<f8188c53>] traverse_pages+0x75/0x89 [xenfs]
Sep 12 22:19:00 ucs-xen24-srv1 kernel:  [<f8189022>] privcmd_ioctl+0x2ad/0x2ea [xenfs]
Sep 12 22:19:00 ucs-xen24-srv1 kernel:  [<f818905f>] ? privcmd_ioctl+0x2ea/0x2ea [xenfs]
Sep 12 22:19:00 ucs-xen24-srv1 kernel:  [<c10884a7>] ? vma_link+0x4f/0x8d
Sep 12 22:19:00 ucs-xen24-srv1 kernel:  [<f8188d75>] ? free_page_list+0x3b/0x3b [xenfs]
Sep 12 22:19:00 ucs-xen24-srv1 kernel:  [<c10a4734>] vfs_ioctl+0x24/0x37
Sep 12 22:19:00 ucs-xen24-srv1 kernel:  [<c10a48a5>] do_vfs_ioctl+0x8a/0x4df
Sep 12 22:19:00 ucs-xen24-srv1 kernel:  [<c1089284>] ? sys_brk+0x101/0x101
Sep 12 22:19:00 ucs-xen24-srv1 kernel:  [<c1089011>] ? do_mmap_pgoff+0x2bb/0x2df
Sep 12 22:19:00 ucs-xen24-srv1 kernel:  [<c10a4d2d>] sys_ioctl+0x33/0x57
Sep 12 22:19:00 ucs-xen24-srv1 kernel:  [<c1251d9c>] sysenter_do_call+0x12/0x2c
Sep 12 22:19:00 ucs-xen24-srv1 kernel: ---[ end trace 4eaa2a86a8e2da26 ]---

 

Following is the code from where the trace is coming. It’s clear from the code that this warning trace is observed only when the debug kernel is used. Also warning appears only once (WARN_ONCE) while starting first domU.

File: linux-3.0.4/arch/x86/xen/mmu.c

#ifdef CONFIG_XEN_DEBUG

pte_t xen_make_pte_debug(pteval_t pte)

{

        phys_addr_t addr = (pte & PTE_PFN_MASK);

        phys_addr_t other_addr;

        bool io_page = false;

        pte_t _pte;

 

        if (pte & _PAGE_IOMAP)

                io_page = true;

 

        _pte = xen_make_pte(pte);

 

        if (!addr)

                return _pte;

 

        if (io_page &&                                                                 

            (xen_initial_domain() || addr >= ISA_END_ADDRESS)) {

                other_addr = pfn_to_mfn(addr >> PAGE_SHIFT) << PAGE_SHIFT;

                WARN_ONCE(addr != other_addr,

                        "0x%lx is using VM_IO, but it is 0x%lx!\n",

                        (unsigned long)addr, (unsigned long)other_addr);

        } else {

                pteval_t iomap_set = (_pte.pte & PTE_FLAGS_MASK) & _PAGE_IOMAP;

                other_addr = (_pte.pte & PTE_PFN_MASK);

                WARN_ONCE((addr == other_addr) && (!io_page) && (!iomap_set),

                        "0x%lx is missing VM_IO (and wasn't fixed)!\n",

                        (unsigned long)addr);

        }

 

        return _pte;

}

PV_CALLEE_SAVE_REGS_THUNK(xen_make_pte_debug);

#endif

When googled, I found this link http://www.gossamer-threads.com/lists/xen/devel/217630, but could not find the patch he is talking about.

Could you please help me resolving this warning? or provide me more pointers and direction for debugging. Thank you in advance.

~Shri

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