Windows System Software -- Consulting, Training, Development -- Unique Expertise, Guaranteed Results

Before Posting...
Please check out the Community Guidelines in the Announcements and Administration Category.

s command don't work

ysys Member - All Emails Posts: 102

Hi dear all,
according to the windbg document , a virtual address is interpreted in a process context (use the process's paging table) , so , if there is not a process context (for example , in debugging winload , which has no concept of process) , s command will not work ,

kd> db 0000000000844000 l2 0000000000844000 4d 5a MZ
kd> s 00000000`00844000 l2 4d 5a

s command return nothing

so , is there any alternative for s command in this situation ?
and why db command works ? it seems interpreting of virtual address in a db command do not use process context.
many thanks!!!

Comments

  • Peter_Viscarola_(OSR)Peter_Viscarola_(OSR) Administrator Posts: 7,223
    edited February 8

    @ys: I saw your post caught in the spam filter. Check out this post... no need for you to repost multiple times.

    Peter

    ETA: I've marked your account to indicate that posts from you should never be considered spam in the future.

    Peter Viscarola
    OSR
    @OSRDrivers

  • raj_rraj_r Member - All Emails Posts: 977
    via Email
    search and display byte both should not work differently

    windbg has broken because of sxe ibp here

    kd> !process 0 0
    **** NT ACTIVE PROCESS DUMP ****
    NULL value in PsActiveProcess List
    kd> ? nt
    Evaluate expression: -2105483264 = 8280e000
    kd> db nt l2
    8280e000 4d 5a MZ
    kd> s nt l2 5a
    8280e001 5a 90 00 03 00 00 00 04-00 00 00 ff ff 00 00 b8 Z...............
  • raj_rraj_r Member - All Emails Posts: 977
    edited February 9 via Email
    @ys it appears there is some bug when using search memory during WinLoad Stage
    i just booted a win-x 32 bit vm (15563 rs2) with /bootdebug on and
    tried to search and it appears it can search for ascii strings but not
    bytes i think you should possibly raise an issue in thier github doc
    account
    kd> kb
     # ChildEBP RetAddr  Args to Child
    00 001a62dc 00746796 00000000 00000000 00000000 winload!BlStatusError+0x62
    01 001a6708 0073e69e 00000000 00000000 00000000 winload!OslFatalErrorEx+0x4c9
    02 001a6f80 0073e29a 001a6fc8 801c80a0 001a6fe8
    winload!OslPrepareTargetPhase0+0x3c2
    03 001a6f90 0073e231 0010be48 004831d0 00061d34 winload!OslpMain+0x13
    04 001a6fe8 0048320a 0010be48 00061d34 00000000 winload!OslMain+0x101
    WARNING: Frame IP not in any known module. Following frames may be wrong.
    05 00000000 f000ff53 f000e2c3 f000ff53 f000ff53 0x48320a
    06 ffffffff 00000000 00e2c3f0 00ff53f0 00ff53f0 0xf000ff53
    kd> r
    eax=00000000 ebx=c0000001 ecx=0081c760 edx=00000060 esi=00000001 edi=0000000f
    eip=0077f821 esp=001a62d4 ebp=001a62dc iopl=0         nv up di pl nz ac pe nc
    cs=0020  ss=0030  ds=0030  es=0030  fs=0060  gs=0060             efl=00000016
    winload!BlStatusError+0x62:
    0077f821 cc              int     3
    kd> dc . l20
    0077f821  5d5e5fcc 8b000cc2 ec8b55ff 81f8e483  ._^].....U......
    0077f831  0001acec 8b565300 57f18bda 0a75db85  .....SV....W..u.
    0077f841  00000db8 0116e9c0 948d0000 00009824  ............$...
    0077f851  3e9ae800 c085fffd 0102880f 448d0000  ...>...........D
    0077f861  44c71824 00001024 44890080 848b1424  $..D$......D$...
    0077f871  00009824 00e88300 83486674 4b7401e8  $.......tfH...tK
    0077f881  01e88348 83481f74 3f7401e8 7401e883  H...t.H...t?...t
    0077f891  0002b80a c5e9c000 b8000000 c00000bb  ................
    kd> s . l50 44 89
    kd> s -b 77f821 77f8a1 44 89
    kd> s -[l2]sa 77f821 77f8a1
    0077f822  "_^]"
    0077f836  "SV"
    0077f860  "D$"
    0077f864  "D$"
    0077f86c  "D$"
    0077f879  "tfH"
    0077f87f  "tKH"
    0077f88b  "t?"
    it also appears you can search for aligned dwords but not bytes
    kd> s -d . l60 0xc00000bb
    0077f89d  c00000bb 0000bbe9 d0e86800 448d0080  .........h.....D
    kd> s -b . l60 0xc0
    kd> s -d . l60 0xc5e9
    kd> s -d . l60 0xc5e9????
    Syntax error at '????'
    kd> s -d . l60 0xc5e9c000
    0077f895  c5e9c000 b8000000 c00000bb 0000bbe9  .............
Sign In or Register to comment.

Howdy, Stranger!

It looks like you're new here. If you want to get involved, click one of these buttons!

Upcoming OSR Seminars
Developing Minifilters 29 July 2019 OSR Seminar Space
Writing WDF Drivers 23 Sept 2019 OSR Seminar Space
Kernel Debugging 21 Oct 2019 OSR Seminar Space
Internals & Software Drivers 18 Nov 2019 Dulles, VA