Re: 2.6.19-rc6-mm2

Andrew Morton
2006-11-29T00:53:45Z

On Tue, 28 Nov 2006 19:24:45 -0500
Thomas Tuttle <thinkinginbinary@gmail.com> wrote:

> I've found a couple of bugs so far...
>
> 1. I did `modprobe kvm' and then tried running a version of the KVM Qemu
> compiled for a different kernel. My mistake. But I got an oops:
>
> BUG: unable to handle kernel NULL pointer dereference at virtual address 00000008
> printing eip:
> f91f9c3f
> *pde = 00000000
> Oops: 0000 [#1]
> SMP
> last sysfs file: /devices/system/cpu/cpu0/cpufreq/scaling_max_freq
> Modules linked in: kvm iTCO_wdt i8k rfcomm l2cap rtc sdhci mmc_block mmc_core hci_usb bluetooth b44 mii ohci1394 ieee1394 uhci_hcd ehci_hcd usbcore psmouse evdev i915 drm cpuid msr speedstep_centrino video thermal processor fan container button battery ac
> CPU: 0
> EIP: 0060:[<f91f9c3f>] Not tainted VLI
> EFLAGS: 00010202 (2.6.19-rc6-mm1 #1)
> EIP is at kvm_vmx_return+0xef/0x4d0 [kvm]
> eax: e5490068 ebx: 00000000 ecx: 00000000 edx: e5491ca4
> esi: 00000000 edi: e5490060 ebp: e5a4fde0 esp: e5a4fd54
> ds: 007b es: 007b ss: 0068
> Process qemu (pid: 24193, ti=e5a4e000 task=c2286a90 task.ti=e5a4e000)
> Stack: 00000002 00000001 f7fe1278 00000002 b7f92000 e5490000 00000000 00000000
> e5a4fdac 00000000 000000d8 f783a580 e5a4fdac c043b98a bfb93f7c f91fa020
> e5a4fde0 bfb93f7c bfb93f7c f91fa0cb 000004f3 c03fb974 e5490000 00000000
> Call Trace:
> [<f91fa020>] kvm_dev_ioctl+0x0/0x1040 [kvm]
> [<f91fa0cb>] kvm_dev_ioctl+0xab/0x1040 [kvm]
> [<c03fb974>] error_code+0x7c/0x84
> [<c011d469>] kmap_atomic+0xc9/0xe0
> [<c018007b>] permission+0x2b/0xd0
> [<c01700d8>] sys_swapon+0x978/0xaf0
> [<c011d263>] kunmap_atomic+0x63/0x70
> [<c011d469>] kmap_atomic+0xc9/0xe0
> [<c011d263>] kunmap_atomic+0x63/0x70
> [<c015cdbd>] get_page_from_freelist+0x27d/0x340
> [<c011d469>] kmap_atomic+0xc9/0xe0
> [<c011d263>] kunmap_atomic+0x63/0x70
> [<c015cdbd>] get_page_from_freelist+0x27d/0x340
> [<c0157af0>] find_get_page+0x20/0x60
> [<c015a75c>] filemap_nopage+0x2dc/0x490
> [<c0178a47>] do_sync_read+0xc7/0x110
> [<c011d469>] kmap_atomic+0xc9/0xe0
> [<c011d263>] kunmap_atomic+0x63/0x70
> [<c0166386>] __handle_mm_fault+0x246/0x9c0
> [<f91fa020>] kvm_dev_ioctl+0x0/0x1040 [kvm]
> [<c030ae02>] scsi_host_alloc+0x202/0x2a0
> [<c018430b>] do_ioctl+0x2b/0x90
> [<c01843cc>] vfs_ioctl+0x5c/0x2b0
> [<c018465d>] sys_ioctl+0x3d/0x70
> [<c0103238>] syscall_call+0x7/0xb
> [<c030ae02>] scsi_host_alloc+0x202/0x2a0
> =======================
> Code: 14 0f 87 77 02 00 00 8b 0c b5 00 15 20 f9 85 c9 0f 84 68 02 00 00 89 ea 89 f8 ff d1 85 c0 0f 84 4c 02 00 00 89 f8 e8 31 e9 ff ff <65> a1 08 00 00 00 8b 40 04 8b 40 08 a8 04 0f 85 ae 02 00 00 e8
> EIP: [<f91f9c3f>] kvm_vmx_return+0xef/0x4d0 [kvm] SS:ESP 0068:e5a4fd54
> msrs: 2
>
> Oh, and I get a ton of these messages with kvm:
>
> rtc: lost some interrupts at 1024Hz.

KVM culprits cc'ed. The KVM patches are I got them didn't even compile on
i386, so runtime breakage isn't very surprising. Looks like you need an
x86_64 machine ;)