Dave,


On Mon, Mar 4, 2013 at 11:17 PM, Dave Anderson <anderson@redhat.com> wrote:


----- Original Message -----
>
>
> Hi,
>
> I met "dis" command not correct issue when use the crash, any idea?
> For built-in "dis" command in crash:
>
> crash> dis task_rq_lock
> 0xc015a2d8 <task_rq_lock>: rscsgt r0, sp, r3, lsl #14
> 0xc015a2dc <task_rq_lock+4>: mrcgt 8, 7, r0, cr2, cr13, {5}
> 0xc015a2e0 <task_rq_lock+8>: mcrvc 8, 4, r3, cr13, cr3, {6}
> 0xc015a2e4 <task_rq_lock+12>: lslsvc r3, r10, r8
> 0xc015a2e8 <task_rq_lock+16>: bl 0xc049fe34
> <__ip_route_output_key+220>
>
>
> But if I use arm-none-linux-gnueabi-gdb to load the vmlinux and do
> the disassemble job, I would see:
>
> (gdb) disas task_rq_lock
> Dump of assembler code for function task_rq_lock:
> 0xc015a2d8 <+0>: push {r4, r5, r6, r7, r8, r10, r11, lr}
> 0xc015a2dc <+4>: add r7, r0, #620 ; 0x26c
> 0xc015a2e0 <+8>: ldr r6, [pc, #100] ; 0xc015a34c <task_rq_lock+116>
> 0xc015a2e4 <+12>: add r11, sp, #28
> 0xc015a2e8 <+16>: mov r5, r0
>
> Thanks,
> Lei

In architecture-specific cases such as this, please put "ARM" predominantly
in the Subject line so as to catch the attention of the ARM maintainers on
this list.

I can't help w/respect to running a native version of ARM, and I
can't reproduce the above with the sample ARM vmcores that I have
on hand.  But using a crash binary built with "make target=ARM" on
an x86_64 host, I see this:


 # crash vmlinux vmcore
 ... [ cut ] ...
 GNU gdb (GDB) 7.3.1
 Copyright (C) 2011 Free Software Foundation, Inc.
 License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
 This is free software: you are free to change and redistribute it.
 There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
 and "show warranty" for details.
 This GDB was configured as "--host=x86_64-unknown-linux-gnu --target=arm-elf-linux"...
 ...

And with --target=arm-elf-linux, I see these results:

2.6.35:

 crash> dis task_rq_lock
 0xc004cd80 <task_rq_lock>:      push    {r4, r5, r11, lr}
 0xc004cd84 <task_rq_lock+4>:    add     r11, sp, #12
 0xc004cd88 <task_rq_lock+8>:    mrs     r3, CPSR
 0xc004cd8c <task_rq_lock+12>:   cpsid   i
 0xc004cd90 <task_rq_lock+16>:   ldr     r4, [pc, #20]   ; 0xc004cdac <task_rq_lock+44>
 0xc004cd94 <task_rq_lock+20>:   str     r3, [r1]
 0xc004cd98 <task_rq_lock+24>:   bl      0xc0073980 <trace_hardirqs_off>
 0xc004cd9c <task_rq_lock+28>:   mov     r0, r4
 0xc004cda0 <task_rq_lock+32>:   bl      0xc028c898 <_raw_spin_lock>
 0xc004cda4 <task_rq_lock+36>:   mov     r0, r4
 0xc004cda8 <task_rq_lock+40>:   pop     {r4, r5, r11, pc}
 0xc004cdac <task_rq_lock+44>:   eorsgt  r6, r9, r8, ror r12
 crash>

2.6.36:

 crash> dis task_rq_lock
 0xc01e69d8 <task_rq_lock>:      push    {r3, r4, r5, r6, r7, r8, r11, lr}
 0xc01e69dc <task_rq_lock+4>:    add     r11, sp, #28
 0xc01e69e0 <task_rq_lock+8>:    mov     r5, r0
 0xc01e69e4 <task_rq_lock+12>:   mov     r4, r1
 0xc01e69e8 <task_rq_lock+16>:   mrs     r3, CPSR
 0xc01e69ec <task_rq_lock+20>:   cpsid   i
 0xc01e69f0 <task_rq_lock+24>:   str     r3, [r4]
 0xc01e69f4 <task_rq_lock+28>:   ldr     r3, [r5, #4]
 0xc01e69f8 <task_rq_lock+32>:   ldr     r8, [pc, #68]   ; 0xc01e6a44 <task_rq_lock+108>
 0xc01e69fc <task_rq_lock+36>:   ldr     r7, [pc, #68]   ; 0xc01e6a48 <task_rq_lock+112>
 0xc01e6a00 <task_rq_lock+40>:   ldr     r3, [r3, #20]
 0xc01e6a04 <task_rq_lock+44>:   ldr     r6, [r8, r3, lsl #2]
 0xc01e6a08 <task_rq_lock+48>:   add     r6, r7, r6
 0xc01e6a0c <task_rq_lock+52>:   mov     r0, r6
 0xc01e6a10 <task_rq_lock+56>:   bl      0xc033dc40 <_raw_spin_lock>
 0xc01e6a14 <task_rq_lock+60>:   ldr     r3, [r5, #4]
 0xc01e6a18 <task_rq_lock+64>:   ldr     r3, [r3, #20]
 0xc01e6a1c <task_rq_lock+68>:   ldr     r3, [r8, r3, lsl #2]
 0xc01e6a20 <task_rq_lock+72>:   add     r7, r7, r3
 0xc01e6a24 <task_rq_lock+76>:   cmp     r6, r7
 0xc01e6a28 <task_rq_lock+80>:   bne     0xc01e6a34 <task_rq_lock+92>
 0xc01e6a2c <task_rq_lock+84>:   mov     r0, r6
 0xc01e6a30 <task_rq_lock+88>:   pop     {r3, r4, r5, r6, r7, r8, r11, pc}
 0xc01e6a34 <task_rq_lock+92>:   mov     r0, r6
 0xc01e6a38 <task_rq_lock+96>:   ldr     r1, [r4]
 0xc01e6a3c <task_rq_lock+100>:  bl      0xc033d7b0 <_raw_spin_unlock_irqrestore>
 0xc01e6a40 <task_rq_lock+104>:  b       0xc01e69e8 <task_rq_lock+16>
 0xc01e6a44 <task_rq_lock+108>:  subgt   r7, r2, r8
 0xc01e6a48 <task_rq_lock+112>:  andsgt  r2, sp, r0, lsr #18
 crash>

2.6.38:

 crash> dis task_rq_lock
 0xc0084864 <task_rq_lock>:      push    {r3, r4, r5, r6, r7, r8, r11, lr}
 0xc0084868 <task_rq_lock+4>:    mov     r5, r0
 0xc008486c <task_rq_lock+8>:    add     r11, sp, #28
 0xc0084870 <task_rq_lock+12>:   mov     r4, r1
 0xc0084874 <task_rq_lock+16>:   mrs     r3, CPSR
 0xc0084878 <task_rq_lock+20>:   cpsid   i
 0xc008487c <task_rq_lock+24>:   str     r3, [r4]
 0xc0084880 <task_rq_lock+28>:   bl      0xc00be9a8 <trace_hardirqs_off>
 0xc0084884 <task_rq_lock+32>:   ldr     r3, [r5, #4]
 0xc0084888 <task_rq_lock+36>:   ldr     r8, [pc, #68]   ; 0xc00848d4 <task_rq_lock+112>
 0xc008488c <task_rq_lock+40>:   ldr     r7, [pc, #68]   ; 0xc00848d8 <task_rq_lock+116>
 0xc0084890 <task_rq_lock+44>:   ldr     r3, [r3, #20]
 0xc0084894 <task_rq_lock+48>:   ldr     r6, [r8, r3, lsl #2]
 0xc0084898 <task_rq_lock+52>:   add     r6, r7, r6
 0xc008489c <task_rq_lock+56>:   mov     r0, r6
 0xc00848a0 <task_rq_lock+60>:   bl      0xc03f1500 <_raw_spin_lock>
 0xc00848a4 <task_rq_lock+64>:   ldr     r3, [r5, #4]
 0xc00848a8 <task_rq_lock+68>:   ldr     r3, [r3, #20]
 0xc00848ac <task_rq_lock+72>:   ldr     r3, [r8, r3, lsl #2]
 0xc00848b0 <task_rq_lock+76>:   add     r7, r7, r3
 0xc00848b4 <task_rq_lock+80>:   cmp     r6, r7
 0xc00848b8 <task_rq_lock+84>:   bne     0xc00848c4 <task_rq_lock+96>
 0xc00848bc <task_rq_lock+88>:   mov     r0, r6
 0xc00848c0 <task_rq_lock+92>:   pop     {r3, r4, r5, r6, r7, r8, r11, pc}
 0xc00848c4 <task_rq_lock+96>:   mov     r0, r6
 0xc00848c8 <task_rq_lock+100>:  ldr     r1, [r4]
 0xc00848cc <task_rq_lock+104>:  bl      0xc03f1ae4 <_raw_spin_unlock_irqrestore>
 0xc00848d0 <task_rq_lock+108>:  b       0xc0084874 <task_rq_lock+16>
 0xc00848d4 <task_rq_lock+112>:  subsgt  r12, r8, r12, asr #28
 0xc00848d8 <task_rq_lock+116>:  andgt   pc, r4, r0, lsl #2
 crash>

But in 3.1.1, the "task_rq_lock" function is renamed to "task_rq_lock.isra.123":

 crash> dis task_rq_lock
 symbol not found: task_rq_lock
 possible alternatives:
   c0015c60 (t) task_rq_lock.isra.123
 crash>

which is also reflected in the vmlinux file:

 crash> !nm -Bn vmlinux | grep task_rq_lock
 c0015c60 t task_rq_lock.isra.123
 crash>

I don't know what "isra" means, but it disassembles OK when used like this:

 crash> dis task_rq_lock.isra.123
 0xc0015c60 <task_rq_lock.isra.123>:     push    {r11, lr}
 0xc0015c64 <task_rq_lock.isra.123+4>:   add     r11, sp, #4
 0xc0015c68 <task_rq_lock.isra.123+8>:   mrs     r3, CPSR
 0xc0015c6c <task_rq_lock.isra.123+12>:  orr     r2, r3, #128    ; 0x80
 0xc0015c70 <task_rq_lock.isra.123+16>:  msr     CPSR_c, r2
 0xc0015c74 <task_rq_lock.isra.123+20>:  str     r3, [r0]
 0xc0015c78 <task_rq_lock.isra.123+24>:  mov     r0, #1
 0xc0015c7c <task_rq_lock.isra.123+28>:  bl      0xc0015ba4 <add_preempt_count>
 0xc0015c80 <task_rq_lock.isra.123+32>:  mov     r0, #1
 0xc0015c84 <task_rq_lock.isra.123+36>:  bl      0xc0015ba4 <add_preempt_count>
 0xc0015c88 <task_rq_lock.isra.123+40>:  ldr     r0, [pc, #0]    ; 0xc0015c90 <task_rq_lock.isra.123+48>
 0xc0015c8c <task_rq_lock.isra.123+44>:  pop     {r11, pc}
 0xc0015c90 <task_rq_lock.isra.123+48>:  eorsgt  lr, r12, r0, asr r2
 crash>

And interestingly enough, gdb accepts the symbol without the "isra.123",
strips it from the text symbol, and it looks like this:

 crash> disass task_rq_lock
 Dump of assembler code for function task_rq_lock:
    0xc0015c60 <+0>:     push    {r11, lr}
    0xc0015c64 <+4>:     add     r11, sp, #4
    0xc0015c68 <+8>:     mrs     r3, CPSR
    0xc0015c6c <+12>:    orr     r2, r3, #128    ; 0x80
    0xc0015c70 <+16>:    msr     CPSR_c, r2
    0xc0015c74 <+20>:    str     r3, [r0]
    0xc0015c78 <+24>:    mov     r0, #1
    0xc0015c7c <+28>:    bl      0xc0015ba4 <add_preempt_count>
    0xc0015c80 <+32>:    mov     r0, #1
    0xc0015c84 <+36>:    bl      0xc0015ba4 <add_preempt_count>
    0xc0015c88 <+40>:    ldr     r0, [pc, #0]    ; 0xc0015c90 <task_rq_lock+48>
    0xc0015c8c <+44>:    pop     {r11, pc}
    0xc0015c90 <+48>:    eorsgt  lr, r12, r0, asr r2
 End of assembler dump.
 crash>

Can the ARM maintainers shed some light on this?  I suppose that
the when the crash utility's "dis" command fails to find an ARM
symbol, but there is one that has ".isra.###" appended, that it
could strip it and use its address?  In the one 3.1.1 ARM kernel
I have, there are 282 of these "isra" text symbols.

That being said, I have no clue as to what's happening in your
case.

Dave


Thanks for helping the diagnosis.
I should admit it is a weird dump image, where I try over the other
dump image, the dis is also working fine.

The kernel version is 3.4, but it doesn't mean the kernel version itself has
any problem, since what I mentioned the other dump image is also created
by the same kernel version.

What make it looks more weird is that dump image could be parsed, and all
basic crash command seems working fine, like ps/log/mod/sys/mount...
 
Thanks,
Lei