Rewriting with StackMods broken

[morehouse]

I'm getting the following assertion failure during rewriting:

performStackMods: /p/paradyn/development/mm/githead/tmp/dyninst/common/src/arch-x86.C:8559: int NS_x86::ia32_decode_opcode(unsigned int, const unsigned char*, NS_x86::ia32_instruction&, NS_x86::ia32_entry**): Assertion "instruct.cond != __null" failed.

Full backtrace:

#0  0x0000003193032625 in raise () from /lib64/libc.so.6
#1  0x0000003193033e05 in abort () from /lib64/libc.so.6
#2  0x000000319302b74e in __assert_fail_base () from /lib64/libc.so.6
#3  0x000000319302b810 in __assert_fail () from /lib64/libc.so.6
#4  0x00007fb784d1d4f7 in NS_x86::ia32_decode_opcode (
    capa=<value optimized out>, addr=<value optimized out>, 
    instruct=<value optimized out>, gotit_ret=0x0)
    at /p/paradyn/development/mm/githead/tmp/dyninst/common/src/arch-x86.C:8559
#5  0x00007fb785fa0275 in insnCodeGen::modifyDisp (newDisp=168, 
    insn=<value optimized out>, gen=..., arch=Dyninst::Arch_x86_64, 
    addr=4403983)
    at /p/paradyn/development/mm/githead/tmp/dyninst/dyninstAPI/src/codegen-x86.C:1331
#6  0x00007fb785f516fa in Dyninst::Relocation::StackModPatch::apply (
    this=0xe3179a0, gen=...)
    at /p/paradyn/development/mm/githead/tmp/dyninst/dyninstAPI/src/Relocation/Widgets/StackModWidget.C:81
#7  0x00007fb785f6941d in Dyninst::Relocation::CodeBuffer::BufferElement::generate (this=0xe317a30, buf=0xb17e038, gen=..., shift=@0xb17e1cc, 
    regenerate=@0x7fff9a30595f)
    at /p/paradyn/development/mm/githead/tmp/dyninst/dyninstAPI/src/Relocation/CodeBuffer.C:117
#8  0x00007fb785f695b7 in Dyninst::Relocation::CodeBuffer::generate (
    this=0xb17e038, baseAddr=<value optimized out>)
    at /p/paradyn/development/mm/githead/tmp/dyninst/dyninstAPI/src/Relocation/CodeBuffer.C:274
#9  0x00007fb785ec6dcb in AddressSpace::generateCode (this=0x138b5b0, cm=..., 
    nearTo=4744750)
    at /p/paradyn/development/mm/githead/tmp/dyninst/dyninstAPI/src/addressSpace.C:1955
#10 0x00007fb785eca300 in AddressSpace::relocateInt (this=0x138b5b0, 
    begin=<value optimized out>, end=<value optimized out>, nearTo=4744750)
    at /p/paradyn/development/mm/githead/tmp/dyninst/dyninstAPI/src/addressSpace.C:1765
#11 0x00007fb785ecb5bb in AddressSpace::relocate (this=0x138b5b0)
    at /p/paradyn/development/mm/githead/tmp/dyninst/dyninstAPI/src/addressSpace.C:1721
#12 0x00007fb785f6c3cc in Dyninst::PatchAPI::DynInstrumenter::run (
    this=<value optimized out>)
    at /p/paradyn/development/mm/githead/tmp/dyninst/dyninstAPI/src/Relocation/DynInstrumenter.C:54
#13 0x00007fb78446862b in Dyninst::PatchAPI::Patcher::run (this=0x1640c00)
    at /p/paradyn/development/mm/githead/tmp/dyninst/patchAPI/src/Command.C:113
#14 0x00007fb7844681da in Dyninst::PatchAPI::Command::commit (this=0x1640c00)
    at /p/paradyn/development/mm/githead/tmp/dyninst/patchAPI/src/Command.C:54
#15 0x00007fb785e94ebc in BPatch_binaryEdit::writeFile (this=0x138b520, 
    outFile=0x560be98 "rewrittenperlbench-orig")
    at /p/paradyn/development/mm/githead/tmp/dyninst/dyninstAPI/src/BPatch_binaryEdit.C:215
#16 0x000000000040467b in main (argc=<value optimized out>, 
    argv=<value optimized out>) at performStackMods.C:516

This issue seems to have been introduced by a series of commits by @jdetter starting with 60f1779.

[jdetter]

Can you do a full rebuild and make sure master is merged into your local branch? I will take a look at this first thing tomorrow morning. Also could I have access to the binary you're running on and your reproducer?

[jdetter]

@wrwilliams depending on the severity of this issue we might want to think about sneaking this into 9.2.X. I suspect this will be a quick fix.

[morehouse]

This issue is on the vanilla master branch. No merging was done.

@jdetter: I'll email you the binary and mutator.

[wrwilliams]

Yes, this is a regression and should be a simple fix.

[jdetter]

@morehouse thanks that will speed this fix up quite a bit.

@wrwilliams I will create a new branch and hopefully have a pull request ready for you to look at tomorrow.

[jdetter]

@morehouse Can you run my patch? I wasn't able to reproduce the assert unfortunately. Here is the git checkout command:

git checkout release9.2/fixes/rewriter_assert

I want to make sure there aren't any followup bugs before I create a pull request for master.

[jdetter]

btw I got a different error when I ran your reproducer, not sure if I did something wrong or not:

./performStackMods called with:
         BIN_FILE = perlbench-orig
         OUT_FILE = perlbench-rewrite
         CANARIES = true
         VERBOSE = false
ADDMODS SUCCEEDED for 0x4741d0
./performStackMods: symbol lookup error: ./performStackMods: undefined symbol: _ZN15BPatch_function7getNameEv

[morehouse]

@jdetter Your patch fixes the issue for me.