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From: "tkoenig at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug fortran/93762] Truncation of deferred-length string when passing as optional
Date: Fri, 10 Apr 2020 16:49:32 +0000 [thread overview]
Message-ID: <bug-93762-4-13PaZRn7Sg@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-93762-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93762
Thomas Koenig <tkoenig at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Ever confirmed|0 |1
Status|UNCONFIRMED |NEW
Last reconfirmed| |2020-04-10
CC| |tkoenig at gcc dot gnu.org
--- Comment #1 from Thomas Koenig <tkoenig at gcc dot gnu.org> ---
Unfortunately, the test case fails with different ways on
current trunk:
$ gfortran -g a.f90
$ ./a.out
at bot of deepest_call, str is "12345"
Program received signal SIGSEGV: Segmentation fault - invalid memory reference.
Backtrace for this error:
#0 0x7f0a66c3059f in ???
at
/usr/src/debug/glibc-2.26-lp151.19.11.1.x86_64/signal/../sysdeps/unix/sysv/linux/x86_64/sigaction.c:0
#1 0x400c65 in __interface_call_m_MOD_interface_call
at /tmp/a.f90:20
#2 0x400d99 in MAIN__
at /tmp/a.f90:32
#3 0x400f0b in main
at /tmp/a.f90:25
Speicherzugriffsfehler (Speicherabzug geschrieben)
(gdb) r a.f90
Starting program: /tmp/a.out a.f90
at bot of deepest_call, str is "12345"
Program received signal SIGSEGV, Segmentation fault.
_gfortran_string_len_trim (s=0x6068d0 "12345", len=<optimized out>) at
../../../gcc/libgfortran/intrinsics/string_intrinsics_inc.c:231
231 if (*((unsigned long*) (s + i + 1)) != blank_longword)
(gdb) p s
$1 = 0x6068d0 "12345"
(gdb) p i
$2 = 564082115390472183
Seems like uninitialzed memory for i.
Valgrind confirms this:
$ valgrind ./a.out
==5621== Memcheck, a memory error detector
==5621== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==5621== Using Valgrind-3.15.0 and LibVEX; rerun with -h for copyright info
==5621== Command: ./a.out
==5621==
at bot of deepest_call, str is "12345"
==5621== Conditional jump or move depends on uninitialised value(s)
==5621== at 0x50A29A5: _gfortran_string_len_trim
(string_intrinsics_inc.c:188)
==5621== by 0x50A2A87: _gfortran_string_trim (string_intrinsics_inc.c:168)
==5621== by 0x400C65: __interface_call_m_MOD_interface_call (a.f90:20)
==5621== by 0x400D99: MAIN__ (a.f90:32)
==5621== by 0x400F0B: main (a.f90:25)
Not sure if this ever worked in a released version.
next parent reply other threads:[~2020-04-10 16:49 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <bug-93762-4@http.gcc.gnu.org/bugzilla/>
2020-04-10 16:49 ` tkoenig at gcc dot gnu.org [this message]
2020-04-10 22:36 ` kargl at gcc dot gnu.org
2020-04-10 23:10 ` sgk at troutmask dot apl.washington.edu
2021-03-12 22:57 ` neil.n.carlson at gmail dot com
2023-12-02 14:15 ` cvs-commit at gcc dot gnu.org
2023-12-10 20:14 ` cvs-commit at gcc dot gnu.org
2023-12-10 20:16 ` anlauf at gcc dot gnu.org
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