Bug#874545: gfortran: when compiled with -fopenmp -O0, application generates a SIGSEGV
Package: gfortran
Version: 4:7.1.0-2
Severity: important
Dear Maintainer,
When compiling/running the NAS Parallel Benchmark suite (OpenMP
implementation, version 3.3.1), I realized that some kernels (for
instance SP) generate a segmentation fault when compiled with -O0
-fopenmp :
$ gdb ./bin/sp.W.x
[...]
(gdb) r
Starting program: /tmp/NPB3.3.1/NPB3.3-OMP/bin/sp.W.x
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
NAS Parallel Benchmarks (NPB3.3-OMP) - SP Benchmark
No input file inputsp.data. Using compiled defaults
Size: 36x 36x 36
Iterations: 400 dt: 0.0015000
Number of available threads: 4
[New Thread 0x7fed13d31700 (LWP 28503)]
[New Thread 0x7fed13530700 (LWP 28504)]
[New Thread 0x7fed12d2f700 (LWP 28505)]
Thread 4 "sp.W.x" received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x7fed12d2f700 (LWP 28505)]
0x0000555555557f00 in exact_rhs_._omp_fn.0 () at exact_rhs.f:22
22 !$omp& jm1,jp1,km1,kp1,dtemp)
(gdb) bt
#0 0x0000555555557f00 in exact_rhs_._omp_fn.0 () at exact_rhs.f:22
#1 0x00007fed14b8c8be in ?? () from /usr/lib/x86_64-linux-gnu/libgomp.so.1
#2 0x00007fed1450a494 in start_thread (arg=0x7fed12d2f700) at
pthread_create.c:333
#3 0x00007fed1424eabf in clone () at ../sysdeps/unix/sysv/linux/x86_64/
clone.S:97
The SIGSEGV happens during the first OpenMP parallel loop.
The problem does not appears when compiling with -O1 -fopenmp, or with -O0
alone.
It does not appear when compiling with gfortran-5.
The problem does appear when compiling with gfortran-6 or gfortran-7 with the
-O0 -fopenmp compile flags
-- System Information:
Debian Release: buster/sid
APT prefers testing
APT policy: (1001, 'testing'), (600, 'unstable'), (500, 'stable'), (1,
'experimental')
Architecture: amd64 (x86_64)
Foreign Architectures: i386
Kernel: Linux 4.12.0-1-amd64 (SMP w/4 CPU cores)
Locale: LANG=fr_FR.utf8, LC_CTYPE=fr_FR.utf8 (charmap=UTF-8), LANGUAGE=
(charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
Versions of packages gfortran depends on:
ii cpp 4:7.1.0-2
ii gcc 4:7.1.0-2
ii gfortran-7 7.2.0-3
gfortran recommends no packages.
Versions of packages gfortran suggests:
pn gfortran-doc <none>
pn gfortran-multilib <none>
-- no debconf information
Reply to: