[xdebug-general] Re: Segmentation-fault in xdebug.so from pkgtools (PHP7?)

Hi Derick,

On 27.01.2016 [09:28:38 +0000], Derick Rethans wrote:
> On Tue, 26 Jan 2016, Nish Aravamudan wrote:
>
> > [ I would have filed this as a bug on http://bugs.xdebug.org, but the
> > captcha is not loading for me. ]
>
> I have fixed that now.

Thanks!

> > I am working on helping vet PHP7.0 in Ubuntu Xenial, potentially, and am
> > hitting the following issue with a recompiled (so as to pull in the PHP7
> > dependencies) pkgtools program (using
> > http://anonscm.debian.org/cgit/pkg-php/pkg-php-tools.git/log/?h=master-7.0):
> >
> > pkgtools
> > Usage:
> > pkgtools COMMAND
> >
> > Options:
> > --help: print help
> > -h: print help
> > --verbose: increase verbosity
> > -v: increase verbosity
> > --sourcedirectory: set source directory
> > -D: set source directory
> >
> > Commands:
> > : Without arguments: print help
> > Segmentation fault (core dumped)
> >
> > The segfault is actually in xdebug.so:
> >
> > line 1150 in xdebug_stack.c:
> >
> > } else if (edata && edata->prev_execute_data && edata->prev_execute_data->opline && edata->prev_execute_data->opline->opcode == ZEND_INCLUDE_OR_EVAL) {
> >
> > I am able to use gdb in a chroot and see:
> >
> > (gdb) print *edata->prev_execute_data
> > $7 = {opline = 0x3, call = 0x4, return_value = 0x0, func = 0xfbcd80, This = {
> > value = {lval = 0, dval = 0, counted = 0x0, str = 0x0, arr = 0x0,
> > obj = 0x0, res = 0x0, ref = 0x0, ast = 0x0, zv = 0x0, ptr = 0x0,
> > ce = 0x0, func = 0x0, ww = {w1 = 0, w2 = 0}}, u1 = {v = {type = 8 '\b',
> > type_flags = 12 '\f', const_flags = 0 '\000', reserved = 2 '\002'},
> > type_info = 33557512}, u2 = {var_flags = 1, next = 1, cache_slot = 1,
> > lineno = 1, num_args = 1, fe_pos = 1, fe_iter_idx = 1}},
> > called_scope = 0x7ffff3203018, prev_execute_data = 0x7ffff3213f20,
> > symbol_table = 0x7ffff327d090, run_time_cache = 0x40000c08,
> > literals = 0x1069c20}
> >
> > where opline is pretty clearly invalid (comparing to other
> > prev_executed_data pointers in the chain).
> >
> > I'm happy to provide more output from gdb, but not really sure where to
> > start :)
>
> Can you instead provide the script to run, and exact steps on how to
> reproduce this? That includes command line arguments, exact PHP and
> Xdebug versions, etc.

xdebug 2.4.0-rc4
php 7.0.2

The script is bin/pkgtools from
http://anonscm.debian.org/cgit/pkg-php/pkg-php-tools.git/log/?h=master-7.0

The core dump occurs regardless of any parameters to pkgtools (i.e.,
just running `pkgtools` should be sufficient).

I reproduce this by spinning up a VM (technically a chroot, but
equivalent for this purpose) with Ubuntu Xenial, and adding a PPA to it
(https://launchpad.net/~php-ubuntu/+archive/ubuntu/php7.0). Update and
`apt-get install pkg-php-tools php-xdebug` and run `pkgtools`.

Thanks,
Nish

-- 
Nishanth Aravamudan
Ubuntu Server
Canonical Ltd