Actually, it just occurred again with I closed gedit.

*** glibc detected *** gedit: double free or corruption (fasttop): 0x0941eec0 ***
======= Backtrace: =========
/lib/tls/i686/cmov/libc.so.6[0xb75885a4]
/lib/tls/i686/cmov/libc.so.6(cfree+0x96)[0xb758a556]
/usr/lib/libglib-2.0.so.0(g_free+0x36)[0xb76e5396]
gedit[0x80bca87]
/usr/lib/libgobject-2.0.so.0(g_object_unref+0x181)[0xb779ff71]
gedit[0x807dd42]
gedit[0x807de0c]
/usr/lib/libgobject-2.0.so.0(g_object_unref+0x181)[0xb779ff71]
gedit(main+0x599)[0x806ab29]
/lib/tls/i686/cmov/libc.so.6(__libc_start_main+0xe5)[0xb752f775]
gedit[0x8069db1]
======= Memory map: ========
08048000-080e1000 r-xp 00000000 08:01 3334455    /usr/bin/gedit
080e1000-080e2000 r--p 00099000 08:01 3334455    /usr/bin/gedit
080e2000-080e4000 rw-p 0009a000 08:01 3334455    /usr/bin/gedit
08cbd000-098e5000 rw-p 08cbd000 00:00 0          [heap]
b52f9000-b5359000 rw-s 00000000 00:09 51839074   /SYSV00000000 (deleted)
b5359000-b53a0000 r--p 00000000 08:01 3491574    /usr/share/fonts/truetype/ttf-dejavu/DejaVuSansMono-Bold.ttf
b53a0000-b5400000 rw-s 00000000 00:09 51806305   /SYSV00000000 (deleted)
b5400000-b5421000 rw-p b5400000 00:00 0 
b5421000-b5500000 ---p b5421000 00:00 0 
b553e000-b554d000 r-xp 00000000 08:01 3563597    /lib/libbz2.so.1.0.4
b554d000-b554e000 r--p 0000f000 08:01 3563597    /lib/libbz2.so.1.0.4
b554e000-b554f000 rw-p 00010000 08:01 3563597    /lib/libbz2.so.1.0.4
b554f000-b5580000 r-xp 00000000 08:01 1089561    /usr/lib/libcroco-0.6.so.3.0.1
b5580000-b5583000 rw-p 00030000 08:01 1089561    /usr/lib/libcroco-0.6.so.3.0.1
b5583000-b55b6000 r-xp 00000000 08:01 3336072    /usr/lib/libgsf-1.so.114.0.11
b55b6000-b55b7000 ---p 00033000 08:01 3336072    /usr/lib/libgsf-1.so.114.0.11
b55b7000-b55b9000 r--p 00033000 08:01 3336072    /usr/lib/libgsf-1.so.114.0.11
b55b9000-b55ba000 rw-p 00035000 08:01 3336072    /usr/lib/libgsf-1.so.114.0.11
b55ba000-b55bb000 rw-p b55ba000 00:00 0 
b55bb000-b55ec000 r-xp 00000000 08:01 3336353    /usr/lib/librsvg-2.so.2.22.3
b55ec000-b55ed000 r--p 00030000 08:01 3336353    /usr/lib/librsvg-2.so.2.22.3
b55ed000-b55ee000 rw-p 00031000 08:01 3336353    /usr/lib/librsvg-2.so.2.22.3
b5601000-b5602000 ---p b5601000 00:00 0 
b5602000-b5e02000 rw-p b5602000 00:00 0 
b5e02000-b5e4e000 r--p 00000000 08:01 3491451    /usr/share/fonts/truetype/ttf-dejavu/DejaVuSansMono.ttf
b5e4e000-b5e5d000 r-xp 00000000 08:01 3335202    /usr/lib/libcryptui.so.0.0.0
b5e5d000-b5e5e000 r--p 0000e000 08:01 3335202    /usr/lib/libcryptui.so.0.0.0
b5e5e000-b5e5f000 rw-p 0000f000 08:01 3335202    /usr/lib/libcryptui.so.0.0.0
b5e68000-b5e69000 r-xp 00000000 08:01 3359182    /usr/lib/gtk-2.0/2.10.0/loaders/svg_loader.so
b5e69000-b5e6a000 r--p 00000000 08:01 3359182    /usr/lib/gtk-2.0/2.10.0/loaders/svg_loader.so
b5e6a000-b5e6b000 rw-p 00001000 08:01 3359182    /usr/lib/gtk-2.0/2.10.0/loaders/svg_loader.so
b5e6b000-b5e6f000 r-xp 00000000 08:01 3359085    /usr/lib/gedit-2/plugins/libmodelines.so
b5e6f000-b5e70000 ---p 00004000 08:01 3359085    /usr/lib/gedit-2/plugins/libmodelines.so
b5e70000-b5e71000 r--p 00004000 08:01 3359085    /usr/lib/gedit-2/plugins/libmodelines.so
b5e71000-b5e72000 rw-p 00005000 08:01 3359085    /usr/lib/gedit-2/plugins/libmodelines.so
b5e7e000-b5e83000 r-xp 00000000 08:01 901131     /usr/lib/gedit-2/plugins/libseahorse-pgp.so
b5e83000-b5e84000 r--p 00004000 08:01 901131     /usr/lib/gedit-2/plugins/libseahorse-pgp.so
b5e84000-b5e85000 rw-p 00005000 08:01 901131     /usr/lib/gedit-2/plugins/libseahorse-pgp.so
b5eb1000-b5ebd000 r-xp 00000000 08:01 3359063    /usr/lib/gio/modules/libgioremote-volume-monitor.so
b5ebd000-b5ebe000 r--p 0000b000 08:01 3359063    /usr/lib/gio/modules/libgioremote-volume-monitor.so
b5ebe000-b5ebf000 rw-p 0000c000 08:01 3359063    /usr/lib/gio/modules/libgioremote-volume-monitor.so
b5ec1000-b5ece000 r-xp 00000000 08:01 3563537    /lib/libgcc_s.so.1
b5ece000-b5ecf000 r--p 0000c000 08:01 3563537    /lib/libgcc_s.so.1
b5ecf000-b5ed0000 rw-p 0000d000 08:01 3563537    /lib/libgcc_s.so.1
b5ee3000-b5f12000 r-xp 00000000 08:01 3434157    /usr/lib/python2.5/lib-dynload/pyexpat.so
b5f12000-b5f14000 r--p 0002e000 08:01 3434157    /usr/liAborted (core dumped)