On 15/09/15 17:03, Thomas DEBESSE wrote: > Hi, I'm replying to this thread from 2013: > http://lists.xen.org/archives/html/xen-devel/2013-03/threads.html#00649 > > Like James Sinclair, all I could find is a closed Debian bug from Dec > 2010 with no resolution: > http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=60770 > > Do you have some news about this bug? > > I got it too with a 3.16 kernel on Debian: > > Sep 15 16:57:14 server kernel: [ 19.844447] ------------[ cut here > ]------------ > Sep 15 16:57:14 server kernel: [ 19.844468] kernel BUG at > /build/linux-sPqfgd/linux-3.16.7-ckt11/arch/x86/xen/enlighten.c:494! > Sep 15 16:57:14 server kernel: [ 19.844479] invalid opcode: 0000 > [#1] SMP > Sep 15 16:57:14 server kernel: [ 19.844487] Modules linked in: fuse > nfsd auth_rpcgss oid_registry nfs_acl nfs lockd fscache sunrpc evdev > coretemp pcspkr ext4 crc16 mbcache jbd2 dm_mod md_mod xen_netfront > xen_blkfront > Sep 15 16:57:14 server kernel: [ 19.844519] CPU: 1 PID: 930 Comm: > cmd Not tainted 3.16.0-4-686-pae #1 Debian 3.16.7-ckt11-1 > Sep 15 16:57:14 server kernel: [ 19.844529] task: e8ba4560 ti: > c29f8000 task.ti: c29f8000 > Sep 15 16:57:14 server kernel: [ 19.844535] EIP: 0061:[<c100373d>] > EFLAGS: 00010282 CPU: 1 > Sep 15 16:57:14 server kernel: [ 19.844545] EIP is at > set_aliased_prot+0x10d/0x120 > Sep 15 16:57:14 server kernel: [ 19.844551] EAX: ffffffea EBX: > ede01000 ECX: cc5ae063 EDX: 80000000 > Sep 15 16:57:14 server kernel: [ 19.844558] ESI: 00000000 EDI: > 80000001 EBP: c29f9dbc ESP: c29f9d98 > Sep 15 16:57:14 server kernel: [ 19.844564] DS: 007b ES: 007b FS: > 00d8 GS: 00e0 SS: 0069 > Sep 15 16:57:14 server kernel: [ 19.844570] CR0: 8005003b CR2: > 00111484 CR3: 029ab000 CR4: 00002660 > Sep 15 16:57:14 server kernel: [ 19.844578] Stack: > Sep 15 16:57:14 server kernel: [ 19.844582] 80000000 cc5ae063 > 001f3c8a ede01000 ecac2140 00000001 ede02000 00000400 > Sep 15 16:57:14 server kernel: [ 19.844594] 00000000 c29f9dd0 > c1003781 c2831ac0 e8892010 c2831ac0 c29f9ddc c10122be > Sep 15 16:57:14 server kernel: [ 19.844606] 00000000 c29f9e00 > c1053fa6 c29f9df0 c1002e90 e8ba4560 ecdcf8c0 00000000 > Sep 15 16:57:14 server kernel: [ 19.844618] Call Trace: > Sep 15 16:57:14 server kernel: [ 19.844628] [<c1003781>] ? > xen_free_ldt+0x31/0x40 > Sep 15 16:57:14 server kernel: [ 19.844640] [<c10122be>] ? > destroy_context+0x2e/0x90 > Sep 15 16:57:14 server kernel: [ 19.844651] [<c1053fa6>] ? > __mmdrop+0x26/0x90 > Sep 15 16:57:14 server kernel: [ 19.844659] [<c1002e90>] ? > xen_end_context_switch+0x10/0x20 > Sep 15 16:57:14 server kernel: [ 19.844668] [<c107c59f>] ? > finish_task_switch+0x9f/0xd0 > Sep 15 16:57:14 server kernel: [ 19.844677] [<c1478e60>] ? > __schedule+0x230/0x6e0 > Sep 15 16:57:14 server kernel: [ 19.844685] [<c116e381>] ? > __sb_end_write+0x31/0x70 > Sep 15 16:57:14 server kernel: [ 19.844694] [<c117361c>] ? > pipe_write+0x34c/0x3d0 > Sep 15 16:57:14 server kernel: [ 19.844703] [<c147be59>] ? > _raw_spin_lock_irqsave+0x19/0x40 > Sep 15 16:57:14 server kernel: [ 19.844713] [<c147baa3>] ? > _raw_spin_unlock_irqrestore+0x13/0x20 > Sep 15 16:57:14 server kernel: [ 19.844723] [<c1090398>] ? > prepare_to_wait+0x48/0x70 > Sep 15 16:57:14 server kernel: [ 19.844732] [<c117324d>] ? > pipe_wait+0x4d/0x80 > Sep 15 16:57:14 server kernel: [ 19.844740] [<c1090680>] ? > prepare_to_wait_event+0xd0/0xd0 > Sep 15 16:57:14 server kernel: [ 19.844749] [<c11737f1>] ? > pipe_read+0x151/0x260 > Sep 15 16:57:14 server kernel: [ 19.844758] [<c116bd96>] ? > new_sync_read+0x66/0xa0 > Sep 15 16:57:14 server kernel: [ 19.844766] [<c116bd30>] ? > default_llseek+0x170/0x170 > Sep 15 16:57:14 server kernel: [ 19.844774] [<c116c620>] ? > vfs_read+0x80/0x150 > Sep 15 16:57:14 server kernel: [ 19.844780] [<c116cdc6>] ? > SyS_read+0x46/0x90 > Sep 15 16:57:14 server kernel: [ 19.844789] [<c147c2df>] ? > sysenter_do_call+0x12/0x12 > Sep 15 16:57:14 server kernel: [ 19.844794] Code: 2e 83 c4 18 5b 5e > 5f 5d c3 90 8d 74 26 00 83 3d d4 92 76 c1 02 75 c8 8d b4 26 00 00 00 > 00 e8 2b 5e 13 00 83 c4 18 5b 5e 5f 5d c3 <0f> 0b 0f 0b 0f 0b 8d b6 00 > 00 00 00 8d bc 27 00 00 00 00 55 89 > Sep 15 16:57:14 server kernel: [ 19.844868] EIP: [<c100373d>] > set_aliased_prot+0x10d/0x120 SS:ESP 0069:c29f9d98 > Sep 15 16:57:14 server kernel: [ 19.844882] ---[ end trace > 5b8a5a9c639bac8c ]--- > > The message above is from DomU kernel. In fact, when I get this > message, I'm lucky: it means the error was handled without crashing. > Most of the case the vm just reboot itself before logging or printing > any message at all. > On Dom0 side, `xl dmesg` shows nothing. > > I downgraded my DomU kernel to 3.2 and it seems to work for now but > it's not a fix. > // > > I was running xen 4.4.1-9 and linux 3.16.7-ckt11-1 (686-pae) from Debian. > > I don't have more information, at all.
The instantiation of HYPERVISOR_update_va_mapping() in set_aliased_prot() has always been buggy in pvops kernels. This bug should be fixed by c/s 0b0e55 "x86/xen: Probe target addresses in set_aliased_prot before the hypercall" which is in the process of being backported to #stable as a prerequisite for the recent LDT CVE fixes. ~Andrew
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