[Bug libfortran/42744] New: SIGSEGV at libgfortran/io/format.c:111

["manfred99 at gmx dot ch" <gcc-bugzilla@gcc.gnu.org>]

In a larger program of mine, I got a SIGSEGV when printing

      WRITE(*,fmtstr)
     &           dat(1),"-",dat(2),"-",dat(3),
     &           datedelim,dat(4),":",dat(5),
     &           (delim,bufarr(pindx),pindx=1,anzarg2)

with gfortran 4.5 (latest snapshot). Using gfortran 4.3.5 the code runs fine.
Unfortunately, I can not reproduce the crash in a standalone program.

In the above print statement, fmtstr is rather large (~550chars).

Here is the gdb output:

Program received signal SIGSEGV, Segmentation fault.
reset_node (fn=0xc) at
../../../gfortran-source/gcc-4.5-20100107/libgfortran/io/format.c:111
111       if (fn->format != FMT_LPAREN)
(gdb) where
#0  reset_node (fn=0xc) at
../../../gfortran-source/gcc-4.5-20100107/libgfortran/io/format.c:111
#1  0x0000000000423b30 in reset_fnode_counters ()
    at ../../../gfortran-source/gcc-4.5-20100107/libgfortran/io/format.c:134
#2  parse_format () at
../../../gfortran-source/gcc-4.5-20100107/libgfortran/io/format.c:1233
#3  0x0000000000418208 in data_transfer_init (dtp=0x7ffffffead80, read_flag=0)
    at ../../../gfortran-source/gcc-4.5-20100107/libgfortran/io/transfer.c:2182
#4  0x000000000040ba86 in writevals (startjul=<value optimized out>,
endjul=<value optimized out>,
    reqts=<value optimized out>, basets=<value optimized out>,
use_monthtu=<value optimized out>,
    station=<value optimized out>, param=<value optimized out>,
aggrtypes=<value optimized out>,
    parfmt2=<value optimized out>, valarr2=<value optimized out>,
datefmt=<value optimized out>,
    delim=<value optimized out>, missing=<value optimized out>, anzarg2=<value
optimized out>,
    anzval=<value optimized out>, toffset=<value optimized out>, qualarr=<value
optimized out>,
    wantqf=<value optimized out>, _station=<value optimized out>, _param=<value
optimized out>,
    _aggrtypes=<value optimized out>, _parfmt2=<value optimized out>,
    _delim=<value optimized out>, _missing=<value optimized out>) at
extractdata.f:1464
#5  0x0000000000407818 in extractdata () at extractdata.f:58
#6  0x0000000000407906 in main (argc=<value optimized out>, argv=<value
optimized out>)
    at extractdata.f:1179
#7  0x000000000042b406 in __libc_start_main (main=<value optimized out>,
    argc=<value optimized out>, ubp_av=<value optimized out>, init=0x42b8b0
<__libc_csu_init>,
    fini=0x42b870 <__libc_csu_fini>, rtld_fini=0, stack_end=0x7fffffffdf98) at
libc-start.c:220
#8  0x0000000000400209 in _start () at ../sysdeps/x86_64/elf/start.S:113
(gdb) list
106       fnode *f;
107
108       fn->count = 0;
109       fn->current = NULL;
110
111       if (fn->format != FMT_LPAREN)
112         return;
113
114       for (f = fn->u.child; f; f = f->next)
115         {


Hopefully this gives already some clues. Otherwise please tell me 
how to debug further.


-- 
           Summary: SIGSEGV at libgfortran/io/format.c:111
           Product: gcc
           Version: 4.5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libfortran
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: manfred99 at gmx dot ch


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42744