Re: [DynInst_API:] PatchFunction blocks() crash

[Bill Williams <bill@xxxxxxxxxxx>]

On 03/10/2015 08:26 PM, Donghai wrote:
> Hi,
>
> I use a very simple program to test the first example of PatchAPI.
>
> Unfortunately, the dyninst gets crash on this example. More
>
> specifically, func->blocks() cause the system segment fault.
>
> The code is pasted as follows, can someone give me some hint?
>
> Thanks.
Can you send us a stack trace from gdb of the fault?

It seems likely that some of our parseAPI optimizations are not playing 
nicely with this example, and that we're assuming data structures are 
populated before they actually are. If adding co->parse() before you 
create the PatchObject eliminates the crash, that's a good way to check 
whether we're being inappropriately lazy.
> Best
> Hai
>
> ParseAPI::SymtabCodeSource *sts;
> ParseAPI::CodeObject *co;
> Address code_base = 0x8048000;
>
> sts = new ParseAPI::SymtabCodeSource( argv[1] );
> co = new ParseAPI::CodeObject( sts );
>
> PatchObject *obj = PatchObject::create(co, code_base);
>
> // Find all functions in the object
> std::vector<PatchFunction*> all;
> obj->funcs(back_inserter(all));
>
> for (std::vector<PatchFunction*>::iterator fi = all.begin();
>       fi != all.end(); fi++) {
>    // Print out each function's name
>    PatchFunction* func = *fi;
>    std::cout << func->name() << std::endl;
>
>    const PatchFunction::Blockset& blks = func->blocks();
>    for (PatchFunction::BlockSet::iterator bi = blks.begin();
>         bi != blks.end(); bi++) {
>      // Print out each block's size
>      PatchBlock* blk = *bi;
>      std::cout << "\tBlock size:" << blk->size() << std::endl;
>    }
> }
>
>
> _______________________________________________
> Dyninst-api mailing list
> Dyninst-api@xxxxxxxxxxx
> https://lists.cs.wisc.edu/mailman/listinfo/dyninst-api

--
--bw

Bill Williams
Paradyn Project
bill@xxxxxxxxxxx