Le 03/03/2011 15:47, Michael S. Tsirkin a écrit :
On Tue, Mar 01, 2011 at 03:39:12PM +0100, Jean-Philippe Menil wrote:
so this time the bug is:
[17882.612303] BUG: unable to handle kernel paging request at
0000000000002458
[17882.612342] IP: [<ffffffffa03898a0>] kvm_set_irq+0x30/0x140 [kvm]
markup_oops give me this:
root@ayrshire:~# cat bug-0103.txt | perl markup_oops.pl -m
/lib/modules/2.6.37.2-dsiun-110105+/kernel/arch/x86/kvm/kvm.ko
/boot/vmlinuz-2.6.37.2-dsiun-110105+
vmaoffset = 18446744072102621184 ffffffffa0389871: 48 89 e5 mov
%rsp,%rbp
ffffffffa0389874: 41 57 push %r15
ffffffffa0389876: 41 89 cf mov %ecx,%r15d | %r15
=> 1 %ecx = 1
ffffffffa0389879: 41 56 push %r14 | %r14
=> ffffffffa038aad0
ffffffffa038987b: 41 55 push %r13
ffffffffa038987d: 49 89 fd mov %rdi,%r13 | %edi
= 0 %r13 => 0
ffffffffa0389880: 41 54 push %r12 | %r12 => 0
ffffffffa0389882: 53 push %rbx
ffffffffa0389883: 89 d3 mov %edx,%ebx | %ebx =>
1a
ffffffffa0389885: 48 81 ec a8 00 00 00 sub $0xa8,%rsp
ffffffffa038988c: 8b 15 00 00 00 00 mov 0x0(%rip),%edx
# ffffffffa0389892<kvm_set_irq+0x22>
ffffffffa0389892: 89 b5 3c ff ff ff mov %esi,-0xc4(%rbp) |
%esi = 0
ffffffffa0389898: 85 d2 test %edx,%edx | %edx => 0
ffffffffa038989a: 0f 85 d5 00 00 00 jne ffffffffa0389975
<kvm_set_irq+0x105>
*ffffffffa03898a0: 49 8b 85 58 24 00 00 mov 0x2458(%r13),%rax |
%eax = 0 %r13 = 0<--- faulting instruction
ffffffffa03898a7: 3b 98 28 01 00 00 cmp 0x128(%rax),%ebx
ffffffffa03898ad: 73 61 jae ffffffffa0389910
<kvm_set_irq+0xa0>
ffffffffa03898af: 89 db mov %ebx,%ebx
ffffffffa03898b1: 48 8b 84 d8 30 01 00 mov 0x130(%rax,%rbx,8),%rax
ffffffffa03898b8: 00
ffffffffa03898b9: 48 85 c0 test %rax,%rax
ffffffffa03898bc: 74 52 je ffffffffa0389910
<kvm_set_irq+0xa0>
ffffffffa03898be: 48 8d 95 40 ff ff ff lea -0xc0(%rbp),%rdx
ffffffffa03898c5: 31 db xor %ebx,%ebx
ffffffffa03898c7: 48 8b 08 mov (%rax),%rcx
ffffffffa03898ca: 83 c3 01 add $0x1,%ebx
ffffffffa03898cd: 0f 18 09 prefetcht0 (%rcx)
ffffffffa03898d0: 48 8b 48 e0 mov -0x20(%rax),%rcx
ffffffffa03898d4: 48 89 0a mov %rcx,(%rdx)
ffffffffa03898d7: 48 8b 48 e8 mov -0x18(%rax),%rcx
ffffffffa03898db: 48 89 4a 08 mov %rcx,0x8(%rdx)
ffffffffa03898df: 48 8b 48 f0 mov -0x10(%rax),%rcx
ffffffffa03898e3: 48 89 4a 10 mov %rcx,0x10(%rdx)
ffffffffa03898e7: 48 8b 48 f8 mov -0x8(%rax),%rcx
ffffffffa03898eb: 48 89 4a 18 mov %rcx,0x18(%rdx)
wich correspond to offset 68a0 (from objdump):
kvm_set_irq():
/usr/src/GIT/linux-2.6-stable/arch/x86/kvm/../../../virt/kvm/irq_comm.c:161
68a0: 49 8b 85 58 24 00 00 mov 0x2458(%r13),%rax
/usr/src/GIT/linux-2.6-stable/arch/x86/kvm/../../../virt/kvm/irq_comm.c:162
68a7: 3b 98 28 01 00 00 cmp 0x128(%rax),%ebx
root@ayrshire:~# addr2line -e
/lib/modules/2.6.37.2-dsiun-110105+/kernel/arch/x86/kvm/kvm.ko
0x68a0
/usr/src/GIT/linux-2.6-stable/arch/x86/kvm/../../../virt/kvm/irq_comm.c:161
So here kvm->irq_routing is null.
How can it be?
Regards.
Not null, this seems to be invalid.
I suspect use after free where the kvm pointer is
pointing at some random memory. Use after free?
Could you please try enabling a slab debugger,
recompile and rerun the test?
Hi,
I'm not sure to activate the right thing.
Is that what you want?
CONFIG_SLAB=y
CONFIG_SLABINFO=y
CONFIG_DEBUG_SLAB=y
CONFIG_DEBUG_SLAB_LEAK=y
Regards.
--
Jean-Philippe Menil - Pôle réseau Service IRTS
DSI Université de Nantes
jean-philippe.me...@univ-nantes.fr
Tel : 02.53.48.49.27 - Fax : 02.53.48.49.09
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