[Bug other/67457] New: segfault in libbacktrace

[Joost.VandeVondele at mat dot ethz.ch]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67457

            Bug ID: 67457
           Summary: segfault in libbacktrace
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: other
          Assignee: unassigned at gcc dot gnu.org
          Reporter: Joost.VandeVondele at mat dot ethz.ch
  Target Milestone: ---

gfortran on trunk uses libbacktrace to print backtraces on error. In an
out-of-memory situation, libbacktrace will fail to print a backtrace and
segfault instead. While having something like a backtrace would be nice (and
other compilers seem to manage), I guess that's difficult. For the segfault gdb
print this:

Starting program: /data/vjoost/gnu/bugs/a.out 
Operating system error: Cannot allocate memory
Allocation would exceed memory limit

Error termination. Backtrace:

Could not print backtrace: mmap: Cannot allocate memory

Could not print backtrace: mmap: Cannot allocate memory

Could not print backtrace: mmap: Cannot allocate memory

Program received signal SIGSEGV, Segmentation fault.
backtrace_free_locked (state=0x7ffff7ecc000, size=3912, addr=0x20b7) at
../../../gcc/libbacktrace/mmap.c:75
75            p->size = size;
(gdb) bt
#0  backtrace_free_locked (state=0x7ffff7ecc000, size=3912, addr=0x20b7) at
../../../gcc/libbacktrace/mmap.c:75
#1  backtrace_free (state=0x7ffff7ecc000, addr=0x20b7, size=3912,
error_callback=<optimized out>, data=<optimized out>)
    at ../../../gcc/libbacktrace/mmap.c:199
#2  0x00007ffff7fcd077 in backtrace_alloc (state=state@entry=0x7ffff7ecc000,
size=size@entry=8376, 
    error_callback=error_callback@entry=0x7ffff7ee8cd0 <error_callback>,
data=data@entry=0x7fffffffde90) at ../../../gcc/libbacktrace/mmap.c:148
#3  0x00007ffff7fcc7f8 in elf_initialize_syminfo (sdata=0x7ffff7ec0620,
data=0x7fffffffde90, error_callback=0x7ffff7ee8cd0 <error_callback>, 
    strtab_size=<optimized out>, strtab=<optimized out>, symtab_size=<optimized
out>, symtab_data=0x7ffff7eb5088 "", base_address=140737352400896, 
    state=0x7ffff7ecc000) at ../../../gcc/libbacktrace/elf.c:380
#4  elf_add (state=<optimized out>, descriptor=<optimized out>,
base_address=140737352400896, error_callback=<optimized out>,
data=0x7fffffffde90, 
    fileline_fn=fileline_fn@entry=0x7fffffffd998, found_sym=0x7fffffffda70,
found_dwarf=0x7fffffffd994, exe=0) at ../../../gcc/libbacktrace/elf.c:748
#5  0x00007ffff7fccc67 in phdr_callback (info=0x7fffffffd9e0, size=<optimized
out>, pdata=0x7fffffffda80) at ../../../gcc/libbacktrace/elf.c:903
#6  0x0000003ba4b26726 in dl_iterate_phdr () from /lib64/libc.so.6
#7  0x00007ffff7fccd30 in backtrace_initialize
(state=state@entry=0x7ffff7ecc000, descriptor=<optimized out>, 
    error_callback=error_callback@entry=0x7ffff7ee8cd0 <error_callback>,
data=data@entry=0x7fffffffde90, fileline_fn=fileline_fn@entry=0x7fffffffdb08)
    at ../../../gcc/libbacktrace/elf.c:944
#8  0x00007ffff7fcb8b4 in fileline_initialize
(state=state@entry=0x7ffff7ecc000,
error_callback=error_callback@entry=0x7ffff7ee8cd0 <error_callback>, 
    data=data@entry=0x7fffffffde90) at ../../../gcc/libbacktrace/fileline.c:136
#9  0x00007ffff7fcb992 in backtrace_pcinfo (state=0x7ffff7ecc000,
pc=140737352994313, callback=0x7ffff7ee8b10 <full_callback>, 
    error_callback=0x7ffff7ee8cd0 <error_callback>, data=0x7fffffffde90) at
../../../gcc/libbacktrace/fileline.c:170
#10 0x00007ffff7fcbe61 in unwind (context=<optimized out>,
vdata=0x7fffffffde50) at ../../../gcc/libbacktrace/backtrace.c:83
#11 0x00007ffff7ea8439 in _Unwind_Backtrace (trace=trace@entry=0x7ffff7fcbe10
<unwind>, trace_argument=trace_argument@entry=0x7fffffffde50)
    at ../../../gcc/libgcc/unwind.inc:295
#12 0x00007ffff7fcbeb5 in backtrace_full (state=state@entry=0x7ffff7ecc000,
skip=skip@entry=0, callback=callback@entry=0x7ffff7ee8b10 <full_callback>, 
    error_callback=error_callback@entry=0x7ffff7ee8cd0 <error_callback>,
data=data@entry=0x7fffffffde90) at ../../../gcc/libbacktrace/backtrace.c:106
#13 0x00007ffff7ee8e0a in _gfortrani_show_backtrace
(in_signal_handler=in_signal_handler@entry=false) at
../../../gcc/libgfortran/runtime/backtrace.c:156
#14 0x00007ffff7ee9906 in _gfortrani_exit_error (status=status@entry=1) at
../../../gcc/libgfortran/runtime/error.c:196
#15 0x00007ffff7ee9b03 in _gfortrani_os_error (message=0x400a28 "Allocation
would exceed memory limit") at ../../../gcc/libgfortran/runtime/error.c:348
#16 0x000000000040081e in foomod::foo (a=..., n=0) at test_1.f90:7
#17 0x00000000004008c0 in MAIN__ () at test_1.f90:16


Testcase:
> cat test_1.f90
MODULE foomod

CONTAINS
  SUBROUTINE foo(a,N)
   INTEGER, DIMENSION(:), POINTER :: a
   INTEGER :: N
   ALLOCATE(a(N))
   a=0
  END SUBROUTINE
END MODULE foomod

USE foomod
INTEGER, DIMENSION(:), POINTER :: a
INTEGER :: N
DO 
CALL foo(a,N)
ENDDO
END


> gfortran -g test_1.f90
> ulimit -v 1000000
> ./a.out
Operating system error: Cannot allocate memory
Allocation would exceed memory limit

Error termination. Backtrace:

Could not print backtrace: mmap: Cannot allocate memory

Could not print backtrace: mmap: Cannot allocate memory

Could not print backtrace: mmap: Cannot allocate memory

Program received signal SIGSEGV: Segmentation fault - invalid memory reference.

Backtrace for this error:
Segmentation fault