Hi Philippe,
I found that I can work around the problem of gdb failing to produce backtraces
by compiling with -O0. Switching to -O1 or higher is enough to cause issues. I
also experimented using dwarf-2, dwarf-3, or dwarf-3 debug information but that
did not seem to matter.
I tried to narrow down the problem with -O1, -gdwarf2, newer valgrind, and
newer gdb:
$ valgrind --tool=massif --vgdb-error=0 ../../Q2D/LamyRidge/src/model/LR_model
==4881== Massif, a heap profiler
==4881== Copyright (C) 2003-2013, and GNU GPL'd, by Nicholas Nethercote
==4881== Using Valgrind-3.10.0 and LibVEX; rerun with -h for copyright info
==4881== Command: ../../Q2D/LamyRidge/src/model/LR_model
[...]
$ gdb ../../Q2D/LamyRidge/src/model/LR_model
GNU gdb (Debian 7.7.1+dfsg-5) 7.7.1
Copyright (C) 2014 Free Software Foundation, Inc.
[...]
(gdb) target remote | /usr/lib/valgrind/../../bin/vgdb --pid=4881
Remote debugging using | /usr/lib/valgrind/../../bin/vgdb --pid=4881
[...]
(gdb) b taehdf5.f90:1936
(gdb) c
(gdb) c
(gdb) b H5FL_reg_calloc
(gdb) c
Continuing.
Breakpoint 2, 0x00000000009a7da0 in H5FL_reg_calloc ()
(gdb) monitor v.info scheduler
[...]
Thread 1: status = VgTs_Runnable
==4881== at 0x9A7DA0: H5FL_reg_calloc (in
/mnt/nfs-home/nrath/Q2D/LamyRidge/src/model/build/LR_model)
==4881== by 0x93DB39: H5A_create (in
/mnt/nfs-home/nrath/Q2D/LamyRidge/src/model/build/LR_model)
==4881== by 0x937C60: H5Acreate2 (in
/mnt/nfs-home/nrath/Q2D/LamyRidge/src/model/build/LR_model)
==4881== by 0x926A0D: h5acreate_c_ (in
/mnt/nfs-home/nrath/Q2D/LamyRidge/src/model/build/LR_model)
==4881== by 0x920E06: h5a_mp_h5acreate_f_ (in
/mnt/nfs-home/nrath/Q2D/LamyRidge/src/model/build/LR_model)
==4881== by 0x6CC1E0: taehdf5_mp_h5dump_attr_int_ (taehdf5.f90:1936)
==4881== by 0x6D2EAB: taehdf5_mp_h5append_data_double_0d_ (taehdf5.f90:4193)
==4881== by 0x6A23F6: plot_m_mp_plots_ (plot_hdf5.f:144)
==4881== by 0x6AC10F: lr_mod_m_mp_check_dt_ (LR_model.F:487)
==4881== by 0x6A4E96: lr_mod_m_mp_lr_step_ (LR_model.F:252)
==4881== by 0x6AC38F: MAIN__ (LR_model.F:544)
==4881== by 0x406F3D: main (in
/mnt/nfs-home/nrath/Q2D/LamyRidge/src/model/build/LR_model)
client stack range: [0xFFEBFE000 0xFFF000FFF] client SP: 0xFFEC2CF78
valgrind stack top usage: 12424 of 1048576
(gdb) bt
#0 0x00000000009a7da0 in H5FL_reg_calloc ()
#1 0x000000000093db3a in H5A_create ()
#2 0x0000000000937c61 in H5Acreate2 ()
#3 0x0000000000926a0e in h5acreate_c_ ()
#4 0x0000000000920e07 in h5a_mp_h5acreate_f_ ()
#5 0x00000000006cc1e1 in taehdf5::h5dump_attr_int (loc_id=1,
[..hangs for a while...]
f=<error reading variable: Cannot access memory at address 0xa000008>,
name=<error reading variable: Cannot access memory at address 0x832f5f9>,
.tmp.NAME.len_V$1086=272)
at /home/nrath/Q2D/utils/src/taehdf5.f90:1936
#6 0x00000000006d2eac in taehdf5::h5append_data_double_0d (group_id=1,
f=<error reading variable: Cannot access memory at address 0xa000008>,
name=<error reading variable: Cannot access memory at address 0x832f5f9>,
.tmp.NAME.len_V$1cd8=272)
at /home/nrath/Q2D/utils/src/taehdf5.f90:4193
#7 0x00000000006a23f7 in plot_m::plots (idt=1) at
/home/nrath/Q2D/LamyRidge/src/model/plot_hdf5.f:144
#8 0x00000000006ac110 in lr_mod_m::check_dt (idt=1)
at /home/nrath/Q2D/LamyRidge/src/model/LR_model.F:487
#9 0x00000000006a4e97 in lr_mod_m::lr_step (idt=1,
dt_r=<error reading variable: Cannot access memory at address 0xa000008>,
t_r=0)
at /home/nrath/Q2D/LamyRidge/src/model/LR_model.F:252
#10 0x00000000006ac390 in lr_model () at
/home/nrath/Q2D/LamyRidge/src/model/LR_model.F:544
So as far as I can tell, valgrind is getting the backtrace right. Is this
correct?
If so, I guess the only explanation is that I am not setting the breakpoint at
the time where massif takes the snapshot?
Best,
-Nikolaus
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