My kernel showed a some kind of bug again, and again it's somehow related to Iceweasel. I had flash animations going on web page (evil proprietary flash player). This time I was able to kill the firefox-bin process and start Iceweasel again: it seems to be working fine, no need to reboot. A syslog excerpt attached.
Apr 3 22:01:12 mithlond kernel: ------------[ cut here ]------------ Apr 3 22:01:12 mithlond kernel: kernel BUG at mm/slab.c:595! Apr 3 22:01:12 mithlond kernel: invalid opcode: 0000 [#1] Apr 3 22:01:12 mithlond kernel: SMP Apr 3 22:01:12 mithlond kernel: Modules linked in: vboxdrv button ac battery ipv6 dm_snapshot dm_mirror dm_mod loop snd_emu10k1_synth snd_emux_synth snd_seq_virmidi snd_seq_midi_emul snd_emu10k1 snd_seq_dummy snd_seq_oss snd_seq_midi snd_seq_midi_event snd_seq snd_rawmidi snd_ac97_codec snd_ac97_bus snd_pcm_oss snd_mixer_oss budget_av dvb_pll saa7146_vv video_buf videodev v4l1_compat v4l2_common snd_pcm budget_core saa7146 snd_seq_device ttpci_eeprom snd_timer snd_page_alloc stv0299 dvb_core snd_util_mem tda10021 tda1004x snd_hwdep snd firmware_class soundcore emu10k1_gp gameport parport_pc parport psmouse rtc serio_raw pcspkr i2c_nforce2 shpchp pci_hotplug i2c_core nvidia_agp agpgart tsdev evdev ext3 jbd mbcache usbhid ide_cd cdrom ide_disk sata_nv libata scsi_mod generic 3c59x mii ohci_hcd ehci_hcd amd74xx ide_core usbcore thermal processor fan Apr 3 22:01:12 mithlond kernel: CPU: 0 Apr 3 22:01:12 mithlond kernel: EIP: 0060:[<c01573e5>] Not tainted VLI Apr 3 22:01:12 mithlond kernel: EFLAGS: 00210206 (2.6.18-4-k7 #1) Apr 3 22:01:12 mithlond kernel: EIP is at kmem_cache_free+0x29/0x6d Apr 3 22:01:12 mithlond kernel: eax: 80010028 ebx: 00000020 ecx: c18df1c0 edx: c16a99e0 Apr 3 22:01:12 mithlond kernel: esi: f54cf460 edi: f54cf460 ebp: f0c307a0 esp: f76f3dec Apr 3 22:01:12 mithlond kernel: ds: 007b es: 007b ss: 0068 Apr 3 22:01:12 mithlond kernel: Process firefox-bin (pid: 3217, ti=f76f2000 task=dffae000 task.ti=f76f2000) Apr 3 22:01:12 mithlond kernel: Stack: 00000020 f54cf460 f0c30800 c027913e f76f3eb4 f0ee3a40 00000000 00000020 Apr 3 22:01:12 mithlond kernel: 00000001 00000001 ffffffa1 00000000 f76f3e94 00000aea 00000000 00000000 Apr 3 22:01:12 mithlond kernel: 00000000 00000000 00000000 0000076c 0000076c 00000c91 000003e8 000003e8 Apr 3 22:01:12 mithlond kernel: Call Trace: Apr 3 22:01:12 mithlond kernel: [<c027913e>] unix_stream_recvmsg+0x33d/0x4a2 Apr 3 22:01:12 mithlond kernel: [<c02224d8>] do_sock_read+0xae/0xb7 Apr 3 22:01:12 mithlond kernel: [<c0222b3f>] sock_aio_read+0x53/0x61 Apr 3 22:01:12 mithlond kernel: [<c015a43b>] do_sync_read+0xb6/0xf1 Apr 3 22:01:12 mithlond kernel: [<c012db81>] autoremove_wake_function+0x0/0x2d Apr 3 22:01:12 mithlond kernel: [<c0222cde>] sock_ioctl+0x191/0x1b3 Apr 3 22:01:12 mithlond kernel: [<c0222b4d>] sock_ioctl+0x0/0x1b3 Apr 3 22:01:12 mithlond kernel: [<c0169908>] do_ioctl+0x1c/0x5d Apr 3 22:01:12 mithlond kernel: [<c015ad55>] vfs_read+0xb0/0x141 Apr 3 22:01:12 mithlond kernel: [<c015b190>] sys_read+0x3c/0x63 Apr 3 22:01:12 mithlond kernel: [<c0102bed>] sysenter_past_esp+0x56/0x79 Apr 3 22:01:12 mithlond kernel: Code: ff ff 57 89 d7 8d 92 00 00 00 40 89 c1 c1 ea 0c 56 c1 e2 05 03 15 90 53 37 c0 53 8b 02 f6 c4 40 74 03 8b 52 0c 8b 02 84 c0 78 08 <0f> 0b 53 02 a1 f0 29 c0 39 4a 18 74 08 0f 0b 6a 0d a1 f0 29 c0 Apr 3 22:01:12 mithlond kernel: EIP: [<c01573e5>] kmem_cache_free+0x29/0x6d SS:ESP 0068:f76f3dec
