Problems tackling a bug

[Sebastian Geerken]

Hi!

I noticed that the current tip of dillo hangs in most cases when
displaying <http://www.dillo.org/>. I succeeded to reproduce this bug
in gdb, but get many "<optimized out>" values. So I tried to reduce
optimization, but unfortunately had problems reproducing this bug:

- "-O2" (standard): reproducable both stand-alone and in gdb;
- "-O1": reproducable stand-alone, but not in gdb;
- "-O0": not reproducable at all.

Versions envolved:

$ gcc --version
gcc (Debian 4.7.2-5) 4.7.2
$ gdb --version
GNU gdb (GDB) 7.4.1-debian

Any ideas?

Sebastian

[e***@public.gmane.org]

Post by Sebastian Geerken
I noticed that the current tip of dillo hangs in most cases when
displaying <http://www.dillo.org/>. I succeeded to reproduce this bug
in gdb, but get many "<optimized out>" values. So I tried to reduce
- "-O2" (standard): reproducable both stand-alone and in gdb;
- "-O1": reproducable stand-alone, but not in gdb;
- "-O0": not reproducable at all.
$ gcc --version
gcc (Debian 4.7.2-5) 4.7.2
$ gdb --version
GNU gdb (GDB) 7.4.1-debian
Any ideas?

I have the same gcc and gdb, and dillo doesn't seem to want to hang
for me. Does it depend on your dillorc options?

[Sebastian Geerken]

Post by e***@public.gmane.org

Post by Sebastian Geerken
I noticed that the current tip of dillo hangs in most cases when
displaying <http://www.dillo.org/>. I succeeded to reproduce this bug
in gdb, but get many "<optimized out>" values. So I tried to reduce
- "-O2" (standard): reproducable both stand-alone and in gdb;
- "-O1": reproducable stand-alone, but not in gdb;
- "-O0": not reproducable at all.
$ gcc --version
gcc (Debian 4.7.2-5) 4.7.2
$ gdb --version
GNU gdb (GDB) 7.4.1-debian
Any ideas?

I have the same gcc and gdb, and dillo doesn't seem to want to hang
for me. Does it depend on your dillorc options?

Removing ~/.dillo makes no difference.

Neither does switching to other versions (gcc and g++ 4.4).

Sebastian

[James C]

So it's probably a heissenbug, depending on the timing between two events.

Options:
- show us the bad backtrace in GDB, in case it rings a bell for someone
- hang the -O1 code, send it SIGABRT to make it dump core, backtrace
the core, and see if it's any better
- someone who knows the code to guess what needs to be slowed down, to
make it reliably reproduceable

Post by Sebastian Geerken

Post by e***@public.gmane.org

Post by Sebastian Geerken
I noticed that the current tip of dillo hangs in most cases when
displaying <http://www.dillo.org/>. I succeeded to reproduce this bug
in gdb, but get many "<optimized out>" values. So I tried to reduce
- "-O2" (standard): reproducable both stand-alone and in gdb;
- "-O1": reproducable stand-alone, but not in gdb;
- "-O0": not reproducable at all.
$ gcc --version
gcc (Debian 4.7.2-5) 4.7.2
$ gdb --version
GNU gdb (GDB) 7.4.1-debian
Any ideas?

I have the same gcc and gdb, and dillo doesn't seem to want to hang
for me. Does it depend on your dillorc options?

Removing ~/.dillo makes no difference.
Neither does switching to other versions (gcc and g++ 4.4).
Sebastian

[Horacio J. Peña]

Maybe valgrind could help you.

Post by Sebastian Geerken
Hi!
I noticed that the current tip of dillo hangs in most cases when
displaying <http://www.dillo.org/>. I succeeded to reproduce this bug
in gdb, but get many "<optimized out>" values. So I tried to reduce
- "-O2" (standard): reproducable both stand-alone and in gdb;
- "-O1": reproducable stand-alone, but not in gdb;
- "-O0": not reproducable at all.
$ gcc --version
gcc (Debian 4.7.2-5) 4.7.2
$ gdb --version
GNU gdb (GDB) 7.4.1-debian
Any ideas?
Sebastian
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[Sebastian Geerken]

Hi!

FYI: For mysterious reasons, I was now able to reproduce this bug with
"-O0" in gdb, so a fix was not so difficult anymore and is now in the
main repository.

Nevertheless, thanks for your help.

Sebastian

PS: (i) "-O1" still showed too much <optimized out>, and (ii) valgrind
did not help, either.