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[Bug 918312] Re: Imprecise instruction pointer for 64bit SIGSEGV

 

[Expired for linux (Ubuntu) because there has been no activity for 60
days.]

** Changed in: linux (Ubuntu)
       Status: Incomplete => Expired

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https://bugs.launchpad.net/bugs/918312

Title:
  Imprecise instruction pointer for 64bit SIGSEGV

Status in “linux” package in Ubuntu:
  Expired

Bug description:
  The instruction pointer passed to a SIGSEGV handler following a (long int) write
  to a protected memory region appears to be imprecise.  In particular, it appears
  to point to the previous instruction.

  This does not appear to be the case for a similar (int) write.

  I have attached a small test program to illustrate this problem.  Below I have included
  a copy of the output of the test program that illustrates what I am seeing.  Note
  that the offending instruction location is identified to the handler as 0x400ea9
  but the offending instruction lives at 0x400eaa.

  The test program requires the library package "libdisasm0" to compile.

  Start of protected memory : 0x1537000

  Disassembly starting at llabel: 
  0x400ea5 : dec	eax (1)
  0x400ea6 : mov	eax, [ebp-0x38] (3)
  0x400ea9 : dec	eax (1)
  0x400eaa : mov	[eax], 0x0000000D (6)
  0x400eb0 : call	0xFFFFFB13 (5)
  0x400eb5 : mov	edi, 0x00000000 (5)
  0x400eba : call	0xFFFFFA93 (5)
  0x400ebf : nop	 (1)
  0x400ec0 : repz ret	 (2)

  SIGSEGV at address : 0x1537000

  Disassembly starting at offending instruction : 
  pc = 0x400ea9
  0x400ea9 : dec	eax (1)
  0x400eaa : mov	[eax], 0x0000000D (6)
  0x400eb0 : call	0xFFFFFB0F (5)
  0x400eb5 : mov	edi, 0x00000000 (5)
  0x400eba : call	0xFFFFFA8F (5)
  0x400ebf : nop	 (1)
  0x400ec0 : repz ret	 (2)

  ProblemType: Bug
  DistroRelease: Ubuntu 10.04
  Package: linux-generic 2.6.32.37.43
  Regression: No
  Reproducible: Yes
  ProcVersionSignature: Ubuntu 2.6.32-37.81-generic 2.6.32.49+drm33.21
  Uname: Linux 2.6.32-37-generic x86_64
  NonfreeKernelModules: nvidia
  AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.21.
  Architecture: amd64
  ArecordDevices:
   **** List of CAPTURE Hardware Devices ****
   card 0: Intel [HDA Intel], device 0: AD198x Analog [AD198x Analog]
     Subdevices: 2/2
     Subdevice #0: subdevice #0
     Subdevice #1: subdevice #1
  AudioDevicesInUse:
   USER        PID ACCESS COMMAND
   /dev/snd/controlC0:  dagreve    4377 F.... pulseaudio
  CRDA: Error: [Errno 2] No such file or directory
  Card0.Amixer.info:
   Card hw:0 'Intel'/'HDA Intel at 0xf7ffc000 irq 16'
     Mixer name	: 'Analog Devices AD1984A'
     Components	: 'HDA:11d4194a,1028026d,00100400'
     Controls      : 34
     Simple ctrls  : 20
  Date: Wed Jan 18 11:11:26 2012
  HibernationDevice: RESUME=UUID=f389f9ee-5683-4f5b-9a5f-1864f8e45b1f
  InstallationMedia: Ubuntu 10.04.2 LTS "Lucid Lynx" - Release amd64 (20110211.1)
  IwConfig:
   lo        no wireless extensions.
   
   eth0      no wireless extensions.
  MachineType: Dell Inc. Precision WorkStation T7500
  ProcCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.32-37-generic root=UUID=08095835-1692-4b9c-8f85-e9b81988317c ro quiet splash
  ProcEnviron:
   SHELL=/bin/bash
   PATH=(custom, user)
   LANG=en_US.UTF-8
  RelatedPackageVersions: linux-firmware 1.34.7
  RfKill:
   
  SourcePackage: linux
  dmi.bios.date: 10/08/2010
  dmi.bios.vendor: Dell Inc.
  dmi.bios.version: A07
  dmi.board.name: 06FW8P
  dmi.board.vendor: Dell Inc.
  dmi.board.version: A01
  dmi.chassis.type: 7
  dmi.chassis.vendor: Dell Inc.
  dmi.modalias: dmi:bvnDellInc.:bvrA07:bd10/08/2010:svnDellInc.:pnPrecisionWorkStationT7500:pvr:rvnDellInc.:rn06FW8P:rvrA01:cvnDellInc.:ct7:cvr:
  dmi.product.name: Precision WorkStation T7500
  dmi.sys.vendor: Dell Inc.

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