Panic when loading kvm-amd.ko

[Michael Hanselmann <linux-kernel-ujPHhMiOvBLtRgLqZ5aouw@public.gmane.org>]

Hello

When loading kvm-amd.ko on an HP DL-145 G5 with one AMD Opteron 2216 HE
(2 cores, 2.4 GHz), I get a kernel panic. I tried to find the exact
cause but was unable to do so. It doesn't crash when I add a "return"
before "wrmsrl(MSR_EFER, efer | MSR_EFER_SVME_MASK);" in
svm_hardware_enable. The backtrace always originates from different
functions, but ends up in interrupt handling every time. This isn't a
regression because it has been happening since at least
2.6.20.something, but I never bothered to look into it. If you need any
more info, please let me know.

I reproduced it with vanilla-2.6.21.5, vanilla-2.6.22-rc5 and current
KVM git. Architecture is x86_64. GCC version is "gcc (GCC) 3.4.6 (Gentoo
Hardened 3.4.6-r2, ssp-3.4.6-1.0, pie-8.7.10)".

Panic with backtrace:
# modprobe kvm-amd
[  142.341948] general protection fault: 0000 [1] SMP
[  142.400582] CPU 0
[  142.424789] Modules linked in: kvm_amd kvm
[  142.474231] Pid: 542, comm: udevd Not tainted 2.6.22-rc4-g6685637b #1
[  142.560608] RIP: 0010:[<ffffffff8801125e>]  [<ffffffff8801125e>] :kvm_amd:svm_hardware_enable+0xa4/0xe1
[  142.673099] RSP: 0018:ffffffff8063ff38  EFLAGS: 00010006
[  142.736615] RAX: 0000000000001d01 RBX: 0000000000000040 RCX: 00000000c0000080
[  142.821935] RDX: 0000000000000000 RSI: 000000008000000a RDI: ffffffff88012e9c
[  142.907256] RBP: ffffffff8063ff78 R08: 00000000ffffffff R09: 0000000000000000
[  142.992577] R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff880111ba
[  143.077898] R13: ffff81003b0d82c0 R14: 00000000ffffffff R15: 0000000000000000
[  143.168925] FS:  00002b957acb06d0(0000) GS:ffffffff805cb000(0000) knlGS:0000000000000000
[  143.265683] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[  143.334385] CR2: 00007fff30143fc8 CR3: 000000003c83c000 CR4: 00000000000006e0
[  143.419705] Process udevd (pid: 542, threadinfo ffff81003cf52000, task ffff81003d245180)
[  143.516463] Stack:  ffffffff8023361a ffff810001019300 ffff805e60000080 000000000000ffff
[  143.612944]  ffff81003cf53c00 0000000000000000 ffffffff880111ba 0000000000000001
[  143.702002]  ffffffff8063ffa8 ffffffff80215308 0000000080526700 ffff81003cf53ce8
[  143.788819] Call Trace:
[  143.820305]  <IRQ>  [<ffffffff8023361a>] _local_bh_enable+0xde/0xf5
[  143.895402]  [<ffffffff880111ba>] :kvm_amd:svm_hardware_enable+0x0/0xe1
[  143.974492]  [<ffffffff80215308>] smp_call_function_interrupt+0x45/0x65
[  144.053582]  [<ffffffff8020a22b>] call_function_interrupt+0x6b/0x70
[  144.128517]  <EOI>  [<ffffffff803142c9>] vsnprintf+0x512/0x5ce
[  144.198421]  [<ffffffff8031433c>] vsnprintf+0x585/0x5ce
[  144.260897]  [<ffffffff80296b1e>] seq_printf+0xb8/0xe1
[  144.322334]  [<ffffffff80247aff>] lockdep_init_map+0x93/0x43c
[  144.391039]  [<ffffffff80245ed7>] debug_mutex_init+0x2e/0x43
[  144.458710]  [<ffffffff80248628>] __lock_acquire+0x780/0xdc8
[  144.526374]  [<ffffffff802bc787>] show_stat+0x31b/0x370
[  144.588848]  [<ffffffff802965d1>] seq_read+0x10a/0x29f
[  144.650285]  [<ffffffff8027d20a>] vfs_read+0xaf/0x132
[  144.710682]  [<ffffffff8027d52c>] sys_read+0x47/0x6e
[  144.770040]  [<ffffffff8020965e>] system_call+0x7e/0x83
[  144.832515]
[  144.850337]
[  144.850338] Code: 0f 30 49 8b 7d 20 41 bc 17 01 01 c0 e8 c9 94 24 f8 49 8b 7d
[  144.957752] RIP  [<ffffffff8801125e>] :kvm_amd:svm_hardware_enable+0xa4/0xe1
[  145.042187]  RSP <ffffffff8063ff38>
[  145.083898] Kernel panic - not syncing: Aiee, killing interrupt handler!

Greets,
Michael

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