Issue 101 in unladen-swallow: Segfault in feedback system

[unladen...@googlecode.com]

Status: Accepted
Owner: collinw
Labels: Type-Defect Priority-High Release-2009Q4

New issue 101 by collinw: Segfault in feedback system
http://code.google.com/p/unladen-swallow/issues/detail?id=101

A --with-pydebug build of Unladen trunk r940 segfaults when running
`Lib/test/regrtest.py -R:: test_funcattrs`. This happens on
both OS X (Apple gcc 4.0.1) and Ubuntu Hardy (gcc 4.2.4), though in
slightly different places:

Backtrace from Hardy:

test_funcattrs
beginning 9 repetitions
123456789
.
Program received signal SIGSEGV, Segmentation fault.
0x0000000000a166ec in std::operator==<unsigned int, unsigned int> (__x=...,
__y=...)
at /usr/include/c++/4.2/bits/stl_pair.h:97
97 { return __x.first == __y.first && __x.second == __y.second; }
(gdb) bt
#0 0x0000000000a166ec in std::operator==<unsigned int, unsigned int>
(__x=..., __y=...)
at /usr/include/c++/4.2/bits/stl_pair.h:97
#1 0x0000000000a16737 in llvm::DenseMapInfo<std::pair<unsigned int,
unsigned int> >::isEqual (
LHS=..., RHS=...)
at
/usr/local/google/collinwinter/llvm-dbg/include/llvm/ADT/DenseMapInfo.h:129
#2 0x0000000000a16795 in llvm::DenseMapIterator<std::pair<unsigned int,
unsigned int>, PyLimitedFeedback,
llvm::DenseMapInfo<std::pair<unsigned int, unsigned int> >,
llvm::DenseMapInfo<PyLimitedFeedback>, false>::AdvancePastEmptyBuckets
(this=0x7fffffffbc20)
at
/usr/local/google/collinwinter/llvm-dbg/include/llvm/ADT/DenseMap.h:484
#3 0x0000000000a167f8 in DenseMapIterator (this=0x7fffffffbc20,
Pos=0x72657469007373,
E=0x726583176ee093)
at
/usr/local/google/collinwinter/llvm-dbg/include/llvm/ADT/DenseMap.h:446
#4 0x0000000000a16831 in llvm::DenseMap<std::pair<unsigned int, unsigned
int>, PyLimitedFeedback,
llvm::DenseMapInfo<std::pair<unsigned int, unsigned int> >,
llvm::DenseMapInfo<PyLimitedFeedback> >::begin (this=0x128ebc4)
at
/usr/local/google/collinwinter/llvm-dbg/include/llvm/ADT/DenseMap.h:76
#5 0x0000000000a1595f in PyFeedbackMap::Clear (this=0x128ebc4)
at ../trunk-pristine/Util/RuntimeFeedback.cc:442
#6 0x0000000000a159bf in PyFeedbackMap_Clear (map=0x128ebc4)
at ../trunk-pristine/Util/RuntimeFeedback.cc:418
#7 0x00007ffff5c523d9 in llvm_clear_feedback (self=0x0, obj=0x1fcd560)
at /usr/local/google/collinwinter/us/trunk-pristine/Modules/_llvm.cc:111
(gdb) p __x
$6 = (
const std::pair<unsigned int, unsigned int> &) @0x72657469007373:
<error reading variable>
(gdb) p __y
$7 = (const std::pair<unsigned int, unsigned int> &) @0x7fffffffbb80:
{first = 4294967295,
second = 4294967295}
(gdb)

I'll append the OS X traceback in an update.

--
You received this message because you are listed in the owner
or CC fields of this issue, or because you starred this issue.
You may adjust your issue notification preferences at:
http://code.google.com/hosting/settings

[unladen...@googlecode.com]

Comment #1 on issue 101 by collinw: Segfault in feedback system
http://code.google.com/p/unladen-swallow/issues/detail?id=101

Traceback on OS X:

test_funcattrs
Reading symbols for shared libraries . done
Reading symbols for shared libraries . done
Reading symbols for shared libraries . done
Reading symbols for shared libraries . done
beginning 9 repetitions
123456789
Reading symbols for shared libraries ..... done
Reading symbols for shared libraries . done
Reading symbols for shared libraries . done
Reading symbols for shared libraries . done
Reading symbols for shared libraries . done
Reading symbols for shared libraries . done
Reading symbols for shared libraries . done
Reading symbols for shared libraries . done
Reading symbols for shared libraries . done
Reading symbols for shared libraries . done
Reading symbols for shared libraries . done
.
Program received signal EXC_BAD_ACCESS, Could not access memory.
Reason: KERN_PROTECTION_FAILURE at address: 0x00000024
0x009388be in llvm::DenseMap<std::pair<unsigned int, unsigned int>,

PyLimitedFeedback, llvm::DenseMapInfo<std::pair<unsigned int, unsigned int>
>,

llvm::DenseMapInfo<PyLimitedFeedback> >::begin (this=0x20) at DenseMap.h:76
76 return iterator(Buckets, Buckets+NumBuckets);
(gdb) bt
#0 0x009388be in llvm::DenseMap<std::pair<unsigned int, unsigned int>,

PyLimitedFeedback, llvm::DenseMapInfo<std::pair<unsigned int, unsigned int>
>,

llvm::DenseMapInfo<PyLimitedFeedback> >::begin (this=0x20) at DenseMap.h:76
#1 0x00937a1c in PyFeedbackMap::Clear (this=0x20)
at ../fast-calls/Util/RuntimeFeedback.cc:442
#2 0x00937a93 in PyFeedbackMap_Clear (map=0x20)
at ../fast-calls/Util/RuntimeFeedback.cc:418
#3 0x01b029e2 in llvm_clear_feedback (self=0x0, obj=0x1e28db8) at
/Users/collinwinter/src/us/hg/fast-calls/Modules/_llvm.cc:111
(gdb) p Buckets
Cannot access memory at address 0x24
(gdb) p this
$1 = (llvm::DenseMap<std::pair<unsigned int, unsigned int>,

PyLimitedFeedback, llvm::DenseMapInfo<std::pair<unsigned int, unsigned int>
>,

llvm::DenseMapInfo<PyLimitedFeedback> > * const) 0x20

[unladen...@googlecode.com]

Updates:
Status: Started

Comment #2 on issue 101 by collinw: Segfault in feedback system
http://code.google.com/p/unladen-swallow/issues/detail?id=101

Problem identified, patch sent for review
(http://codereview.appspot.com/180083).

[unladen...@googlecode.com]

Updates:
Status: Fixed

Comment #3 on issue 101 by collinw: Segfault in feedback system
http://code.google.com/p/unladen-swallow/issues/detail?id=101

Fixed in r941.