Re: [Synaptic-devel] Strange segfault

[Andrey Tarassov]

Panu Matilainen wrote:
> On Thu, 2004-04-15 at 20:56, Andrey Tarassov wrote:
>
> > Hi!
> >
> > I have encountered a very strange problem with synaptic? Namely, we have 
> > a repository that may be accessed from both http and ftp using the same 
> > address and the repository is signed with GPG.
> >
> > Now, the problem is that if you press the refresh button on startup 
> > (after some time this is not even required) and edit repositories, 
> > pressing refresh again causes synaptic to crash.
> >
> > There is only one thing I am editing in repositories: ftp -> http and 
> > vice versa. Nothing else. I also encountered this problem before with 
> > some other changes, but know I have found a possibility to reproduce the 
> > bug easily.
> >
> > I looked deeper into the problem and tried to trace the problem with 
> > gdb. I found that the segfault appeared in pkgAcqIndexRel::Done(), but 
> > could not find why it was happening as everything seemed to be ok.
> >
> > Have you heard about such a problem and does anyone know about how to 
> > solve it?
> >
> > FYI, I am using synaptic-0.48.1 and apt-rpm 0.15.5cnc6.
>
>
> That sounds a whole lot like a longstanding problem I'm seeing with
> apt-shell together with signed repositories:
>
> When running "update" from apt-shell, by the time it gets to 
> pkgAcqIndexRel::Done(), Repository->Vendor->FingerPrint has turned into 
> garbage, causing the segfault on comparison to Release fingerprint.
> Actually most of the Vendor stucture gets overwritten by something, it
> seems consistent that the corruption begins at the last character of
> Vendor->Description (but not 100% sure about that), anyway the entire
> Vendor Repository->Vendor struct get garbled useless.
>
> Doesn't happen with synaptic in my environment but it sounds all too
> familiar - can you post the entire backtrace of the crash so we can see
> whether it's the same problem or something else?

Yes, sure. Here we go:

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread -150645536 (LWP 22413)]
pkgAcqIndexRel::Done (this=0x908b960, Message=Cannot access memory at 
address 0x0
) at basic_string.h:257
257           { return &((reinterpret_cast<_Rep*> (_M_data()))[-1]); }
(gdb) bt
#0  pkgAcqIndexRel::Done (this=0x908b960, Message=Cannot access memory 
at address 0x0
) at basic_string.h:257
#1  0x0073b26a in pkgAcquire::Worker::RunMessages (this=0x9093b80) at 
acquire-worker.cc:280
#2  0x0073ddbc in pkgAcquire::Worker::InFdReady (this=0x9093b80) at 
acquire-worker.cc:501
#3  0x00728968 in pkgAcquire::RunFds (this=0xfff5f6f5, RSet=0xfeef6a50, 
WSet=0xfeef69d0) at acquire.cc:300
#4  0x00728ba0 in pkgAcquire::Run (this=0xfeef6b20) at acquire.cc:349
#5  0x080aed2d in RPackageLister::updateCache (this=0x8e12ef0, 
status=0xfff5f6f5) at rpackagelister.cc:1435
#6  0x0808277a in RGMainWindow::updateClicked (self=0x8e5e7d0, 
data=0x8e03030) at rgmainwindow.cc:693
#7  0x00643691 in g_cclosure_marshal_VOID__VOID () from 
/usr/lib/libgobject-2.0.so.0
#8  0x0062f160 in g_closure_invoke () from /usr/lib/libgobject-2.0.so.0
#9  0x00643195 in g_signal_emit_by_name () from /usr/lib/libgobject-2.0.so.0
#10 0x00642157 in g_signal_emit_valist () from /usr/lib/libgobject-2.0.so.0
#11 0x00642454 in g_signal_emit () from /usr/lib/libgobject-2.0.so.0
#12 0x0032d425 in gtk_button_clicked () from /usr/lib/libgtk-x11-2.0.so.0
#13 0x0032e3bb in gtk_button_get_relief () from /usr/lib/libgtk-x11-2.0.so.0
#14 0x00643691 in g_cclosure_marshal_VOID__VOID () from 
/usr/lib/libgobject-2.0.so.0
#15 0x0062f4f7 in g_cclosure_new_swap () from /usr/lib/libgobject-2.0.so.0
#16 0x0062f160 in g_closure_invoke () from /usr/lib/libgobject-2.0.so.0
#17 0x006429be in g_signal_emit_by_name () from /usr/lib/libgobject-2.0.so.0
#18 0x00642157 in g_signal_emit_valist () from /usr/lib/libgobject-2.0.so.0
#19 0x00642454 in g_signal_emit () from /usr/lib/libgobject-2.0.so.0
#20 0x0032d375 in gtk_button_released () from /usr/lib/libgtk-x11-2.0.so.0
#21 0x0032e23b in gtk_button_get_relief () from /usr/lib/libgtk-x11-2.0.so.0
#22 0x003e7854 in gtk_marshal_VOID__UINT_STRING () from 
/usr/lib/libgtk-x11-2.0.so.0
#23 0x0062f4f7 in g_cclosure_new_swap () from /usr/lib/libgobject-2.0.so.0
#24 0x0062f160 in g_closure_invoke () from /usr/lib/libgobject-2.0.so.0
#25 0x00642bc5 in g_signal_emit_by_name () from /usr/lib/libgobject-2.0.so.0
#26 0x00641f2e in g_signal_emit_valist () from /usr/lib/libgobject-2.0.so.0
#27 0x00642454 in g_signal_emit () from /usr/lib/libgobject-2.0.so.0
#28 0x004e53b5 in gtk_widget_send_expose () from 
/usr/lib/libgtk-x11-2.0.so.0
#29 0x003e5df2 in gtk_propagate_event () from /usr/lib/libgtk-x11-2.0.so.0
#30 0x003e4b36 in gtk_main_do_event () from /usr/lib/libgtk-x11-2.0.so.0
#31 0x002538e5 in gdk_x11_register_standard_event_type () from 
/usr/lib/libgdk-x11-2.0.so.0
#32 0x007cde4a in g_main_depth () from /usr/lib/libglib-2.0.so.0
#33 0x007cef28 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#34 0x007cf260 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#35 0x007cf8a3 in g_main_loop_run () from /usr/lib/libglib-2.0.so.0
#36 0x003e4403 in gtk_main () from /usr/lib/libgtk-x11-2.0.so.0
#37 0x08068c5d in main (argc=1, argv=0xfeef7df4) at gsynaptic.cc:216


In general I believe that you described the situation quite correctly. 
Do you know if the apt-rpm developers are aware about the problem?

I will try to look into this problem deeper, but unfortunately I do not 
have that much time for this :-(

Thanks,

Andrey

--
Andrey Tarasov
Software Engineer

OÜ SOT Finnish Software Engineering
Kreutzwaldi 7-4, 10124 TALLINN, ESTONIA

Phone: +372 641 9975
Fax:   +372 641 9876
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