Re: Oops in VMA code
From: Alexander Graf
Date: Thu Jun 16 2011 - 01:32:25 EST
On 16.06.2011, at 06:32, Linus Torvalds wrote:
> On Wed, Jun 15, 2011 at 2:59 PM, Alexander Graf <agraf@xxxxxxx> wrote:
>> Hi memory management experts,
>>
>> I just had this crash while compiling code on my PPC G5. I was running my PPC KVM tree, which was pretty much 06e86849cf4019945a106913adb9ff0abcc01770 plus a few unrelated KVM patches. User space is 64-bit.
>>
>> Is this a known issue or did I hit something completely unexpected?
>
> It doesn't look at all familiar to me, nor does google really seem to
> find anything half-way related.
Thanks a lot for looking at it either way :).
> In fact, the only thing that that oops makes me think is that we
> should get rid of that find_vma_prev() function these days (the vma
> list is doubly linked since commit 297c5eee3724, and the whole "look
> up prev" thing is some silly old stuff).
>
> But that's an entirely unrelated issue.
>
> Also, your disassembly and your gdb line lookup is apparently from
> some other kernel, because the addresses don't match. The actual
> running kernel actually says
>
> NIP [c000000000190598] .do_munmap+0x138/0x3f0
>
> so it's do_munmap, not find_vma_prev(). Although gdb claiming
> find_vma_prev() might be from some inlining issue, of course.
> Regardless, it's useless for debugging - it's the do_munap()
> disassembly we'd want (but I'm no longer all that fluent in ppc
> assembly anyway, so ir probably wouldn't help).
The reason the symbol lookup here is wrong is because I manually stripped the kernel, since yaboot chokes on loading a 250MB elf binary with debug symbols included:
clay:/autotest/ppc/kvm # gdb /boot/vmlinux.autotest.unstrip
...
(gdb) x /i 0xc000000000190598
0xc000000000190598 <find_vma_prev+68>: ld r0,16(r26)
(gdb) x /i do_munmap+0x138
0xc000000000190598 <find_vma_prev+68>: ld r0,16(r26)
clay:/autotest/ppc/kvm # gdb /boot/vmlinux.autotest
(gdb) x /i 0xc000000000190598
0xc000000000190598: ld r0,16(r26)
The latter is the one I'm executing, while the former still has all the symbols. But you're right. It looks like this is simply an inlined function - which is why it got stripped away. Here's the disassembly of the whole do_unmap function. I hope it's of use despite your fading PPC asm skills :). Host compiler is gcc 4.3.4 from SLES11SP1.
0xc000000000190460 <do_munmap>: mflr r0
0xc000000000190464 <do_munmap+4>: std r29,-24(r1)
0xc000000000190468 <do_munmap+8>: std r30,-16(r1)
0xc00000000019046c <do_munmap+12>: mfcr r12
0xc000000000190470 <do_munmap+16>: std r0,16(r1)
0xc000000000190474 <do_munmap+20>: clrldi. r0,r4,52
0xc000000000190478 <do_munmap+24>: mr r29,r3
0xc00000000019047c <do_munmap+28>: std r31,-8(r1)
0xc000000000190480 <do_munmap+32>: std r23,-72(r1)
0xc000000000190484 <do_munmap+36>: std r24,-64(r1)
0xc000000000190488 <do_munmap+40>: std r25,-56(r1)
0xc00000000019048c <do_munmap+44>: std r26,-48(r1)
0xc000000000190490 <do_munmap+48>: std r27,-40(r1)
0xc000000000190494 <do_munmap+52>: std r28,-32(r1)
0xc000000000190498 <do_munmap+56>: stw r12,8(r1)
0xc00000000019049c <do_munmap+60>: ld r30,-18136(r2)
0xc0000000001904a0 <do_munmap+64>: stdu r1,-192(r1)
0xc0000000001904a4 <do_munmap+68>: mr r31,r4
0xc0000000001904a8 <do_munmap+72>: beq 0xc0000000001904f0 <get_current>
0xc0000000001904ac <remove_vma_list>: li r3,-22
0xc0000000001904b0 <do_munmap+80>: addi r1,r1,192
0xc0000000001904b4 <do_munmap+84>: ld r0,16(r1)
0xc0000000001904b8 <do_munmap+88>: lwz r12,8(r1)
0xc0000000001904bc <do_munmap+92>: ld r23,-72(r1)
0xc0000000001904c0 <do_munmap+96>: ld r24,-64(r1)
0xc0000000001904c4 <do_munmap+100>: ld r25,-56(r1)
0xc0000000001904c8 <do_munmap+104>: ld r26,-48(r1)
0xc0000000001904cc <do_munmap+108>: ld r27,-40(r1)
0xc0000000001904d0 <do_munmap+112>: ld r28,-32(r1)
0xc0000000001904d4 <do_munmap+116>: mtlr r0
0xc0000000001904d8 <do_munmap+120>: ld r29,-24(r1)
0xc0000000001904dc <do_munmap+124>: ld r30,-16(r1)
0xc0000000001904e0 <do_munmap+128>: mtocrf 8,r12
0xc0000000001904e4 <do_munmap+132>: ld r31,-8(r1)
0xc0000000001904e8 <do_munmap+136>: blr
0xc0000000001904ec <do_munmap+140>: nop
0xc0000000001904f0 <get_current>: ld r9,456(r13)
0xc0000000001904f4 <test_ti_thread_flag>: ld r11,8(r9)
0xc0000000001904f8 <do_munmap+152>: ld r8,-32712(r30)
0xc0000000001904fc <do_munmap+156>: lis r10,4096
0xc000000000190500 <do_munmap+160>: rldicr r10,r10,16,47
0xc000000000190504 <test_bit>: ld r0,128(r11)
0xc000000000190508 <do_munmap+168>: rldicr r0,r0,59,4
0xc00000000019050c <do_munmap+172>: sradi r0,r0,63
0xc000000000190510 <do_munmap+176>: and r0,r0,r8
0xc000000000190514 <do_munmap+180>: add r0,r0,r10
0xc000000000190518 <do_munmap+184>: cmpld cr7,r0,r4
0xc00000000019051c <do_munmap+188>: blt cr7,0xc0000000001904ac <remove_vma_list>
0xc000000000190520 <get_current>: ld r9,456(r13)
0xc000000000190524 <test_ti_thread_flag>: ld r11,8(r9)
0xc000000000190528 <test_bit>: ld r0,128(r11)
0xc00000000019052c <do_munmap+204>: rldicr r0,r0,59,4
0xc000000000190530 <do_munmap+208>: sradi r0,r0,63
0xc000000000190534 <do_munmap+212>: and r0,r0,r8
0xc000000000190538 <do_munmap+216>: add r0,r0,r10
0xc00000000019053c <do_munmap+220>: subf r0,r4,r0
0xc000000000190540 <do_munmap+224>: cmpld cr7,r0,r5
0xc000000000190544 <do_munmap+228>: blt cr7,0xc0000000001904ac <remove_vma_list>
0xc000000000190548 <do_munmap+232>: addi r0,r5,4095
0xc00000000019054c <do_munmap+236>: rldicr. r4,r0,0,51
0xc000000000190550 <do_munmap+240>: beq 0xc0000000001904ac <remove_vma_list>
0xc000000000190554 <find_vma_prev>: cmpdi cr7,r3,0
0xc000000000190558 <find_vma_prev+4>: beq cr7,0xc0000000001907f0 <remove_vma_list+836>
0xc00000000019055c <find_vma_prev+8>: ld r9,8(r3)
0xc000000000190560 <find_vma_prev+12>: ld r28,0(r3)
0xc000000000190564 <find_vma_prev+16>: li r11,0
0xc000000000190568 <find_vma_prev+20>: li r26,0
0xc00000000019056c <find_vma_prev+24>: cmpdi cr7,r9,0
0xc000000000190570 <find_vma_prev+28>: bne cr7,0xc000000000190594 <find_vma_prev+64>
0xc000000000190574 <find_vma_prev+32>: b 0xc0000000001905d0 <do_munmap+368>
0xc000000000190578 <find_vma_prev+36>: nop
0xc00000000019057c <find_vma_prev+40>: nop
0xc000000000190580 <find_vma_prev+44>: ld r9,16(r9)
0xc000000000190584 <find_vma_prev+48>: mr r26,r11
0xc000000000190588 <find_vma_prev+52>: cmpdi cr7,r9,0
0xc00000000019058c <find_vma_prev+56>: mr r11,r26
0xc000000000190590 <find_vma_prev+60>: beq cr7,0xc0000000001905c4 <find_vma_prev+112>
0xc000000000190594 <find_vma_prev+64>: addi r26,r9,-56
0xc000000000190598 <find_vma_prev+68>: ld r0,16(r26)
0xc00000000019059c <find_vma_prev+72>: cmpld cr7,r31,r0
0xc0000000001905a0 <find_vma_prev+76>: blt cr7,0xc000000000190580 <find_vma_prev+44>
0xc0000000001905a4 <find_vma_prev+80>: ld r11,24(r26)
0xc0000000001905a8 <find_vma_prev+84>: cmpdi cr7,r11,0
0xc0000000001905ac <find_vma_prev+88>: beq cr7,0xc0000000001905c4 <find_vma_prev+112>
0xc0000000001905b0 <find_vma_prev+92>: ld r0,16(r11)
0xc0000000001905b4 <find_vma_prev+96>: cmpld cr7,r31,r0
0xc0000000001905b8 <find_vma_prev+100>: blt cr7,0xc0000000001905c4 <find_vma_prev+112>
0xc0000000001905bc <find_vma_prev+104>: ld r9,8(r9)
0xc0000000001905c0 <find_vma_prev+108>: b 0xc000000000190588 <find_vma_prev+52>
0xc0000000001905c4 <find_vma_prev+112>: cmpdi cr7,r26,0
0xc0000000001905c8 <find_vma_prev+116>: beq cr7,0xc0000000001905d0 <do_munmap+368>
0xc0000000001905cc <find_vma_prev+120>: ld r28,24(r26)
0xc0000000001905d0 <do_munmap+368>: cmpdi cr7,r28,0
0xc0000000001905d4 <do_munmap+372>: beq cr7,0xc0000000001907f0 <remove_vma_list+836>
0xc0000000001905d8 <do_munmap+376>: ld r0,8(r28)
0xc0000000001905dc <do_munmap+380>: add r24,r4,r31
0xc0000000001905e0 <do_munmap+384>: cmpld cr7,r24,r0
0xc0000000001905e4 <do_munmap+388>: ble cr7,0xc0000000001907f0 <remove_vma_list+836>
0xc0000000001905e8 <do_munmap+392>: cmpld cr7,r31,r0
0xc0000000001905ec <do_munmap+396>: ble cr7,0xc00000000019061c <do_munmap+444>
0xc0000000001905f0 <do_munmap+400>: ld r0,16(r28)
0xc0000000001905f4 <do_munmap+404>: cmpld cr7,r24,r0
0xc0000000001905f8 <do_munmap+408>: blt cr7,0xc000000000190814 <do_munmap+948>
0xc0000000001905fc <do_munmap+412>: mr r3,r29
0xc000000000190600 <do_munmap+416>: mr r4,r28
0xc000000000190604 <do_munmap+420>: mr r5,r31
0xc000000000190608 <do_munmap+424>: li r6,0
0xc00000000019060c <do_munmap+428>: bl 0xc000000000190160 <__split_vma>
0xc000000000190610 <do_munmap+432>: cmpdi r3,0
0xc000000000190614 <do_munmap+436>: bne 0xc0000000001904b0 <do_munmap+80>
0xc000000000190618 <do_munmap+440>: mr r26,r28
0xc00000000019061c <do_munmap+444>: mr r3,r29
0xc000000000190620 <do_munmap+448>: mr r4,r24
0xc000000000190624 <do_munmap+452>: bl 0xc00000000018e580 <find_vma>
0xc000000000190628 <do_munmap+456>: cmpdi r3,0
0xc00000000019062c <do_munmap+460>: beq 0xc00000000019063c <do_munmap+476>
0xc000000000190630 <do_munmap+464>: ld r0,8(r3)
0xc000000000190634 <do_munmap+468>: cmpld cr7,r24,r0
0xc000000000190638 <do_munmap+472>: bgt cr7,0xc000000000190830 <do_munmap+976>
0xc00000000019063c <do_munmap+476>: cmpdi cr4,r26,0
0xc000000000190640 <do_munmap+480>: beq cr4,0xc00000000019071c <do_munmap+700>
0xc000000000190644 <do_munmap+484>: ld r25,24(r26)
0xc000000000190648 <do_munmap+488>: ld r0,168(r29)
0xc00000000019064c <do_munmap+492>: cmpdi cr7,r0,0
0xc000000000190650 <do_munmap+496>: bne cr7,0xc0000000001906b0 <do_munmap+592>
0xc000000000190654 <detach_vmas_to_be_unmapped>: beq cr4,0xc00000000019080c <detach_vmas_to_be_unmapped+440>
0xc000000000190658 <detach_vmas_to_be_unmapped+4>: addi r27,r26,24
0xc00000000019065c <detach_vmas_to_be_unmapped+8>: li r0,0
0xc000000000190660 <detach_vmas_to_be_unmapped+12>: addi r23,r29,8
0xc000000000190664 <detach_vmas_to_be_unmapped+16>: mr r28,r25
0xc000000000190668 <detach_vmas_to_be_unmapped+20>: std r0,32(r25)
0xc00000000019066c <detach_vmas_to_be_unmapped+24>: b 0xc000000000190680 <detach_vmas_to_be_unmapped+44>
0xc000000000190670 <detach_vmas_to_be_unmapped+28>: ld r0,8(r4)
0xc000000000190674 <detach_vmas_to_be_unmapped+32>: cmpld cr7,r24,r0
0xc000000000190678 <detach_vmas_to_be_unmapped+36>: ble cr7,0xc000000000190724 <detach_vmas_to_be_unmapped+208>
0xc00000000019067c <detach_vmas_to_be_unmapped+40>: mr r28,r4
0xc000000000190680 <detach_vmas_to_be_unmapped+44>: mr r4,r23
0xc000000000190684 <detach_vmas_to_be_unmapped+48>: addi r3,r28,56
0xc000000000190688 <detach_vmas_to_be_unmapped+52>: bl 0xc00000000043b1c0 <rb_erase>
0xc00000000019068c <detach_vmas_to_be_unmapped+56>: nop
0xc000000000190690 <detach_vmas_to_be_unmapped+60>: lwz r9,88(r29)
0xc000000000190694 <detach_vmas_to_be_unmapped+64>: addi r9,r9,-1
0xc000000000190698 <detach_vmas_to_be_unmapped+68>: stw r9,88(r29)
0xc00000000019069c <detach_vmas_to_be_unmapped+72>: ld r4,24(r28)
0xc0000000001906a0 <detach_vmas_to_be_unmapped+76>: cmpdi cr6,r4,0
0xc0000000001906a4 <detach_vmas_to_be_unmapped+80>: bne cr6,0xc000000000190670 <detach_vmas_to_be_unmapped+28>
0xc0000000001906a8 <detach_vmas_to_be_unmapped+84>: std r4,0(r27)
0xc0000000001906ac <detach_vmas_to_be_unmapped+88>: b 0xc00000000019072c <detach_vmas_to_be_unmapped+216>
0xc0000000001906b0 <do_munmap+592>: cmpdi cr7,r25,0
0xc0000000001906b4 <do_munmap+596>: beq cr7,0xc000000000190654 <detach_vmas_to_be_unmapped>
0xc0000000001906b8 <do_munmap+600>: ld r11,8(r25)
0xc0000000001906bc <do_munmap+604>: cmpld cr7,r24,r11
0xc0000000001906c0 <do_munmap+608>: ble cr7,0xc000000000190654 <detach_vmas_to_be_unmapped>
0xc0000000001906c4 <do_munmap+612>: mr r28,r25
0xc0000000001906c8 <do_munmap+616>: ld r0,48(r28)
0xc0000000001906cc <do_munmap+620>: rldicl. r9,r0,51,63
0xc0000000001906d0 <do_munmap+624>: beq 0xc000000000190700 <do_munmap+672>
0xc0000000001906d4 <do_munmap+628>: ld r0,16(r28)
0xc0000000001906d8 <do_munmap+632>: ld r9,168(r29)
0xc0000000001906dc <munlock_vma_pages_all>: mr r3,r28
0xc0000000001906e0 <do_munmap+640>: subf r0,r11,r0
0xc0000000001906e4 <do_munmap+644>: rldicl r0,r0,52,12
0xc0000000001906e8 <do_munmap+648>: subf r9,r0,r9
0xc0000000001906ec <do_munmap+652>: std r9,168(r29)
0xc0000000001906f0 <munlock_vma_pages_all+20>: ld r4,8(r28)
0xc0000000001906f4 <munlock_vma_pages_all+24>: ld r5,16(r28)
0xc0000000001906f8 <munlock_vma_pages_all+28>: bl 0xc00000000018d840 <munlock_vma_pages_range>
0xc0000000001906fc <munlock_vma_pages_all+32>: nop
0xc000000000190700 <do_munmap+672>: ld r28,24(r28)
0xc000000000190704 <do_munmap+676>: cmpdi cr7,r28,0
0xc000000000190708 <do_munmap+680>: beq cr7,0xc000000000190654 <detach_vmas_to_be_unmapped>
0xc00000000019070c <do_munmap+684>: ld r11,8(r28)
0xc000000000190710 <do_munmap+688>: cmpld cr7,r24,r11
0xc000000000190714 <do_munmap+692>: bgt cr7,0xc0000000001906c8 <do_munmap+616>
0xc000000000190718 <do_munmap+696>: b 0xc000000000190654 <detach_vmas_to_be_unmapped>
0xc00000000019071c <do_munmap+700>: ld r25,0(r29)
0xc000000000190720 <do_munmap+704>: b 0xc000000000190648 <do_munmap+488>
0xc000000000190724 <detach_vmas_to_be_unmapped+208>: std r4,0(r27)
0xc000000000190728 <detach_vmas_to_be_unmapped+212>: std r26,32(r4)
0xc00000000019072c <detach_vmas_to_be_unmapped+216>: li r9,0
0xc000000000190730 <detach_vmas_to_be_unmapped+220>: ld r0,-32720(r30)
0xc000000000190734 <detach_vmas_to_be_unmapped+224>: std r9,24(r28)
0xc000000000190738 <detach_vmas_to_be_unmapped+228>: ld r9,32(r29)
0xc00000000019073c <detach_vmas_to_be_unmapped+232>: cmpd cr7,r9,r0
0xc000000000190740 <detach_vmas_to_be_unmapped+236>: beq cr7,0xc000000000190800 <detach_vmas_to_be_unmapped+428>
0xc000000000190744 <detach_vmas_to_be_unmapped+240>: beq cr6,0xc0000000001907f8 <detach_vmas_to_be_unmapped+420>
0xc000000000190748 <detach_vmas_to_be_unmapped+244>: ld r4,8(r4)
0xc00000000019074c <detach_vmas_to_be_unmapped+248>: ld r0,0(r9)
0xc000000000190750 <detach_vmas_to_be_unmapped+252>: std r2,40(r1)
0xc000000000190754 <detach_vmas_to_be_unmapped+256>: mr r3,r29
0xc000000000190758 <detach_vmas_to_be_unmapped+260>: mtctr r0
0xc00000000019075c <detach_vmas_to_be_unmapped+264>: ld r11,16(r9)
0xc000000000190760 <detach_vmas_to_be_unmapped+268>: ld r2,8(r9)
0xc000000000190764 <detach_vmas_to_be_unmapped+272>: bctrl
0xc000000000190768 <detach_vmas_to_be_unmapped+276>: ld r2,40(r1)
0xc00000000019076c <detach_vmas_to_be_unmapped+280>: li r0,0
0xc000000000190770 <do_munmap+784>: mr r5,r26
0xc000000000190774 <do_munmap+788>: mr r6,r31
0xc000000000190778 <do_munmap+792>: mr r7,r24
0xc00000000019077c <detach_vmas_to_be_unmapped+296>: std r0,16(r29)
0xc000000000190780 <do_munmap+800>: mr r3,r29
0xc000000000190784 <do_munmap+804>: mr r4,r25
0xc000000000190788 <do_munmap+808>: bl 0xc00000000018ee70 <unmap_region>
0xc00000000019078c <update_hiwater_vm>: ld r9,160(r29)
0xc000000000190790 <update_hiwater_vm+4>: ld r0,152(r29)
0xc000000000190794 <update_hiwater_vm+8>: cmpld cr7,r0,r9
0xc000000000190798 <update_hiwater_vm+12>: bge cr7,0xc0000000001907b4 <vma_pages>
0xc00000000019079c <update_hiwater_vm+16>: std r9,152(r29)
0xc0000000001907a0 <update_hiwater_vm+20>: b 0xc0000000001907b4 <vma_pages>
0xc0000000001907a4 <update_hiwater_vm+24>: nop
0xc0000000001907a8 <update_hiwater_vm+28>: nop
0xc0000000001907ac <update_hiwater_vm+32>: nop
0xc0000000001907b0 <update_hiwater_vm+36>: ld r9,160(r29)
0xc0000000001907b4 <vma_pages>: ld r0,8(r25)
0xc0000000001907b8 <vma_pages+4>: ld r6,16(r25)
0xc0000000001907bc <remove_vma_list+784>: mr r3,r29
0xc0000000001907c0 <vma_pages+12>: subf r6,r0,r6
0xc0000000001907c4 <vma_pages+16>: rldicl r6,r6,52,12
0xc0000000001907c8 <remove_vma_list+796>: subf r0,r6,r9
0xc0000000001907cc <remove_vma_list+800>: neg r6,r6
0xc0000000001907d0 <remove_vma_list+804>: std r0,160(r29)
0xc0000000001907d4 <remove_vma_list+808>: ld r4,48(r25)
0xc0000000001907d8 <remove_vma_list+812>: ld r5,152(r25)
0xc0000000001907dc <remove_vma_list+816>: bl 0xc00000000018e290 <vm_stat_account>
0xc0000000001907e0 <remove_vma_list+820>: mr r3,r25
0xc0000000001907e4 <remove_vma_list+824>: bl 0xc00000000018ec30 <remove_vma>
0xc0000000001907e8 <remove_vma_list+828>: mr. r25,r3
0xc0000000001907ec <remove_vma_list+832>: bne 0xc0000000001907b0 <update_hiwater_vm+36>
0xc0000000001907f0 <remove_vma_list+836>: li r3,0
0xc0000000001907f4 <remove_vma_list+840>: b 0xc0000000001904b0 <do_munmap+80>
0xc0000000001907f8 <detach_vmas_to_be_unmapped+420>: ld r4,40(r29)
0xc0000000001907fc <detach_vmas_to_be_unmapped+424>: b 0xc00000000019074c <detach_vmas_to_be_unmapped+248>
0xc000000000190800 <detach_vmas_to_be_unmapped+428>: beq cr4,0xc0000000001907f8 <detach_vmas_to_be_unmapped+420>
0xc000000000190804 <detach_vmas_to_be_unmapped+432>: ld r4,16(r26)
0xc000000000190808 <detach_vmas_to_be_unmapped+436>: b 0xc00000000019074c <detach_vmas_to_be_unmapped+248>
0xc00000000019080c <detach_vmas_to_be_unmapped+440>: mr r27,r29
0xc000000000190810 <detach_vmas_to_be_unmapped+444>: b 0xc00000000019065c <detach_vmas_to_be_unmapped+8>
0xc000000000190814 <do_munmap+948>: ld r9,-32728(r30)
0xc000000000190818 <do_munmap+952>: lwz r11,88(r29)
0xc00000000019081c <do_munmap+956>: li r3,-12
0xc000000000190820 <do_munmap+960>: lwz r0,0(r9)
0xc000000000190824 <do_munmap+964>: cmpw cr7,r11,r0
0xc000000000190828 <do_munmap+968>: blt cr7,0xc0000000001905fc <do_munmap+412>
0xc00000000019082c <do_munmap+972>: b 0xc0000000001904b0 <do_munmap+80>
0xc000000000190830 <do_munmap+976>: mr r4,r3
0xc000000000190834 <do_munmap+980>: mr r5,r24
0xc000000000190838 <do_munmap+984>: mr r3,r29
0xc00000000019083c <do_munmap+988>: li r6,1
0xc000000000190840 <do_munmap+992>: bl 0xc000000000190160 <__split_vma>
0xc000000000190844 <do_munmap+996>: cmpdi r3,0
0xc000000000190848 <do_munmap+1000>: beq 0xc00000000019063c <do_munmap+476>
0xc00000000019084c <do_munmap+1004>: b 0xc0000000001904b0 <do_munmap+80>
Alex
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