GDB 7.2 gets SIGSEGV when step into a function in a shared library

Liang Cheng
2011-09-16T20:04:17Z

Yao/Hui,

Built a gdbserver based on gdb 7.3.1,  and I get the exactly same error.
The gdb that I used is arm-eabi-4.4.3.

Here is debug output. Next step is to try gdb trunk.
thanks

Breakpoint 1, main (argc=1, argv=0xbed00cb4) at vendor/altestavplayback.c:284
284         CheckErr(res);
1: x/i $pc
=> 0x8d12 <main+78>:    ldr     r0, [r7, #52]   ; 0x34
(gdb) n
286         z = xa_fun_in_lib(10);
1: x/i $pc
=> 0x8d18 <main+84>:    mov.w   r0, #10
(gdb) set debug infrun 1
(gdb) show debug infrun
Inferior debugging is 1.
(gdb) s
infrun: clear_proceed_status_thread (Thread 746.746)
infrun: proceed (addr=0xffffffff, signal=144, step=1)
infrun: resume (step=1, signal=0), trap_expected=0
infrun: wait_for_inferior (treat_exec_as_sigtrap=0)
infrun: target_wait (-1, status) =
infrun:   746 [Thread 746.746],
infrun:   status->kind = stopped, signal = SIGTRAP
infrun: infwait_normal_state
infrun: TARGET_WAITKIND_STOPPED
infrun: stop_pc = 0x8d1c
infrun: software single step trap for Thread 746.746
infrun: stepping inside range [0x8d18-0x8d24]
infrun: resume (step=1, signal=0), trap_expected=0
infrun: prepare_to_wait
infrun: target_wait (-1, status) =
infrun:   746 [Thread 746.746],
infrun:   status->kind = stopped, signal = SIGTRAP
infrun: infwait_normal_state
infrun: TARGET_WAITKIND_STOPPED
infrun: stop_pc = 0x8628
infrun: software single step trap for Thread 746.746
infrun: stepped into dynsym resolve code
infrun: resume (step=1, signal=0), trap_expected=0
infrun: prepare_to_wait
infrun: target_wait (-1, status) =
infrun:   746 [Thread 746.746],
infrun:   status->kind = stopped, signal = SIGTRAP
infrun: infwait_normal_state
infrun: TARGET_WAITKIND_STOPPED
infrun: stop_pc = 0x862c
infrun: software single step trap for Thread 746.746
infrun: stepped into dynsym resolve code
infrun: resume (step=1, signal=0), trap_expected=0
infrun: prepare_to_wait
infrun: target_wait (-1, status) =
infrun:   746 [Thread 746.746],
infrun:   status->kind = stopped, signal = SIGTRAP
infrun: infwait_normal_state
infrun: TARGET_WAITKIND_STOPPED
infrun: stop_pc = 0x8630
infrun: software single step trap for Thread 746.746
infrun: stepped into dynsym resolve code
infrun: resume (step=1, signal=0), trap_expected=0
infrun: prepare_to_wait
infrun: target_wait (-1, status) =
infrun:   746 [Thread 746.746],
infrun:   status->kind = stopped, signal = SIGSEGV
infrun: infwait_normal_state
infrun: TARGET_WAITKIND_STOPPED
infrun: stop_pc = 0x8d22
infrun: random signal 11

Program received signal SIGSEGV, Segmentation fault.
infrun: stop_stepping
0x00008d22 in main (argc=1, argv=0xbed00cb4) at vendor/altestavplayback.c:286
286         z = xa_fun_in_lib(10);
1: x/i $pc
=> 0x8d22 <main+94>:    str     r3, [r7, #44]   ; 0x2c

On Fri, Sep 16, 2011 at 8:55 AM, Yao Qi <yao@codesourcery.com> wrote:
> On 09/16/2011 12:39 AM, Liang Cheng wrote:
>> Sorry for not being clear.
>> Here is the debug session getting SIGSEGV. xa_fun_in_lib is the
>> function defined in shared library, and its symbols has been found by
>> gdb.  Step instruction also caused the same issue. The reason that I
>> attach those disassemble dump is to avoid rounds of ask-give.  Let me
>> know if disassemble of the piece of code is needed.  Any idea of why
>> it happens?
>>
>
> This debug session is much clear than last one.  Thanks.
>
>> Breakpoint 1, main (argc=1, argv=0xbef25ca4) at vendor/altestavplayback.c:284
>> 284         CheckErr(res);
>> 3: x/i $pc
>> => 0x8d12 <main+78>:    ldr     r0, [r7, #52]   ; 0x34
>> (gdb) n
>> 286         z = xa_fun_in_lib(10);
>> 3: x/i $pc
>> => 0x8d18 <main+84>:    mov.w   r0, #10
>> (gdb) s
>>
>
> Before you run `step', turn on some debug output first.  Like this `set
> debug infrun 1'.  Then, when you run `step', you can see some debug
> output, which will show how PC is changed and events inferior gets
> during command `step'.
>
> However, before we go into the details of debug output, could you check
> whether GDB cvs trunk works or not.  You just have to build gdb for arm,
> and I think GDB cvs trunk should be able to work with your 7.2 gdbserver.
>
>> Program received signal SIGSEGV, Segmentation fault.
>> 0x00008d22 in main (argc=1, argv=0xbef25ca4) at vendor/altestavplayback.c:286
>> 286         z = xa_fun_in_lib(10);
>> 3: x/i $pc
>> => 0x8d22 <main+94>:    str     r3, [r7, #44]   ; 0x2c
>> (gdb) info address xa_fun_in_lib
>> Symbol "xa_fun_in_lib(int)" is a function at address 0x800036fc.
>>
>> On Thu, Sep 15, 2011 at 11:13 AM, Yao Qi <yao@codesourcery.com> wrote:
>>> On 09/15/2011 12:21 AM, Liang Cheng wrote:
>
>
>
> --
> Yao (齐尧)
>