firstly, you should try to see if it crashes if you disable all extensions.

secondtly, you'll need to recompile gnome-shell, gtk3, cogl and atk with debug symbols and attach gdb to your gnome-shell process and try to crash it and get from gdb a backtrace.

Without extensions the problem occurs too.

I'm trying to debug with gdb.

For more information about debugging, see also: https://wiki.archlinux.org/index.php/Step_By_Step_Debugging_Guide

I confirm the issue.
Nov 18 18:52:32 localhost kernel: [25749.507966] traps: gnome-shell[8672] trap int3 ip:7f2752a3fa27 sp:7fff4a912e00 error:0
Nov 18 18:52:32 localhost gnome-session[22413]: WARNING: Detected that screensaver has left the bus
Nov 18 18:52:32 localhost gnome-session[22413]: WARNING: Application 'gnome-shell.desktop' killed by signal 5

But I have no libatk error.

It usually happens after some idle time.

I compiled gnome-shell with debug options, but i couldn't reproduce this error using gdb.

Does it restart automatically or do you have to ALT+F2, "r", <ENTER>?

Does it also occur when you press the WINDOWS key? (meaning the problem is not necessarely on the hot corner, but on the activities menu)

Are you using nvidia/nouveau?

It restart automatically. sometimes it doesn't appear and i can't run ALT+F2.
It occour with both (hotcorner and rwindows key), using catalyst and radeon oss driver

My case is that when it crashes, all the windows are disappeared.
It seems that this only happens when not hitting the hot corner for a long time.
(on x86_64)

I am using nvidia and it restarts automatically.
I don't use WINDOWS key.

I can confirm this issue, too on a freshly installed system. I'm using nvidia-304xx-lts.

Apr 5 08:34:20 Asus_A6 kernel: [ 6123.869628] gnome-shell[1439]: segfault at 3 ip b58fc6a1 sp bfae7fd0 error 4 in libatk-1.0.so.0.20609.1[b58f0000+1e000]
Apr 5 08:34:22 Asus_A6 gnome-session[1362]: WARNING: Detected that screensaver has left the bus
Apr 5 08:34:22 Asus_A6 gnome-session[1362]: WARNING: Application 'gnome-shell.desktop' killed by signal 11

As far as I learned about that it occurs when hitting hot corner or any items on the panel after some idle time.
I haven't found anything about this bug in gnome bugzilla. Can it be an Arch specific issue?

Still here after the last update. Now the favourites bar is missing in the Activities after it's automatic restart. It is back after a manual restart.
And yes, it is happening after a some time of not touching the Activities space.

crash with gnome-shell 3.8.2 too.
here is the log from dmesg:

[ 535.556743] gnome-shell[1316]: segfault at 250 ip 00007fc9744be710 sp 00007fffd7739418 error 4 in libglib-2.0.so.0.3600.2[7fc974486000+fc000]
[ 537.732097] systemd-journald[129]: Failed to write entry, ignoring: Argument list too long
[ 585.958375] gnome-shell[3871]: segfault at 1 ip 00007f176b1aa710 sp 00007fff36dc7868 error 4 in libglib-2.0.so.0.3600.2[7f176b172000+fc000]
[ 587.418420] systemd-journald[129]: Failed to write entry, ignoring: Argument list too long

I confirm the issue still exists on gnome-shell 3.8.3-1. Sometimes the crash is so serious that gdm crashes and I have to restart it (losing all my previous work). Seems more like a critical bug to me.

Also, when it crashes with a lot of virtual desktops open, the shell doesn't restore the windows to the proper virtual desktops

This bug still exists in gnome-shell 3.8.3-2.Architecture x86_64.
log from dmesg:
========================
[ 4404.425334] gnome-shell[815]: segfault at 1 ip 00007f9438d08670 sp 00007fffb9a8a718 error 4 in libglib-2.0.so.0.3600.3[7f9438cd0000+fc000]
[ 4407.837136] systemd-journald[130]: Failed to write entry, ignoring: Argument list too long

Reproduced with Nouveau on NVIDIA

status? upstream report?

I don't seem to have any issue with the hot corner anymore. I am using gnome-shell 3.10.3-1