I'm not quite sure what triggered this, but the operation being done was:
- mounted cifs share, worked
- tried 'cd mountpoint', then ssh hanged, but ping was still working. Screen went blank and keyboard stopped.

After rebooting, same procedure worked just fine.

Dmesg snippet follows:
Jun  5 10:20:55 localhost kernel: [241594.728076] FS-Cache: Loaded
Jun  5 10:20:55 localhost kernel: [241594.759708] Key type dns_resolver registered
Jun  5 10:20:55 localhost kernel: [241594.821347] FS-Cache: Netfs 'cifs' registered for caching
Jun  5 10:20:55 localhost kernel: [241594.821906] Key type cifs.spnego registered
Jun  5 10:20:55 localhost kernel: [241594.821948] Key type cifs.idmap registered
Jun  5 10:20:58 localhost kernel: [241597.192234] BUG: unable to handle kernel paging request at 4611c000
Jun  5 10:20:58 localhost kernel: [241597.192579] IP: [<c0547642>] kmem_cache_alloc+0x52/0x1c0
Jun  5 10:20:58 localhost kernel: [241597.192849] *pdpt = 000000003299e001 *pde = 0000000000000000
Jun  5 10:20:58 localhost kernel: [241597.193024] Oops: 0000 [#1] SMP
Jun  5 10:20:58 localhost kernel: [241597.193024] Modules linked in: arc4 md4 nls_utf8 cifs dns_resolver fscache rtl8180 rtl8187 eeprom_93cx6 mac80211 cfg80211 fuse ipt_MASQUERADE nf_conntrack_netbios_ns nf_conntrack_broadcast ip6table_nat nf_nat_ipv6 ip6table_mangle ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 iptable_nat nf_nat_ipv4 nf_nat iptable_mangle rfcomm bnep nf_conntrack_ipv4 nf_defrag_ipv4 xt_conntrack nf_conntrack ebtable_filter ebtables ip6table_filter ip6_tables iTCO_wdt iTCO_vendor_support msi_wmi sparse_keymap snd_hda_codec_realtek acpi_cpufreq mperf coretemp snd_hda_intel snd_hda_codec snd_hwdep snd_seq snd_seq_device snd_pcm uvcvideo videobuf2_vmalloc videobuf2_memops videobuf2_core videodev media snd_page_alloc snd_timer microcode snd joydev lpc_ich soundcore btusb bluetooth mfd_core rfkill r8169 mii wmi uinput i915 i2c_algo_bit drm_kms_helper drm i2c_core video ums_realtek usb_storage [last unloaded: rtl8187]
Jun  5 10:20:58 localhost kernel: [241597.193024] Pid: 9550, comm: bash Not tainted 3.9.4-300.fc19.i686.PAE #1 LG Electronics X110-L.B7WHP1/X110
Jun  5 10:20:58 localhost kernel: [241597.193024] EIP: 0060:[<c0547642>] EFLAGS: 00010206 CPU: 0
Jun  5 10:20:58 localhost kernel: [241597.193024] EIP is at kmem_cache_alloc+0x52/0x1c0
Jun  5 10:20:58 localhost kernel: [241597.193024] EAX: 00000000 EBX: e7addfe0 ECX: 0064efa5 EDX: 4611c000
Jun  5 10:20:58 localhost kernel: [241597.193024] ESI: 4611c000 EDI: f5801300 EBP: f29bbecc ESP: f29bbea0
Jun  5 10:20:58 localhost kernel: [241597.193024]  DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068
Jun  5 10:20:58 localhost kernel: [241597.193024] CR0: 8005003b CR2: 4611c000 CR3: 25120000 CR4: 000007e0
Jun  5 10:20:58 localhost kernel: [241597.193024] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000
Jun  5 10:20:58 localhost kernel: [241597.193024] DR6: ffff0ff0 DR7: 00000400
Jun  5 10:20:58 localhost kernel: [241597.193024] Process bash (pid: 9550, ti=f29ba000 task=c87d4c80 task.ti=f29ba000)
Jun  5 10:20:58 localhost kernel: [241597.193024] Stack:
Jun  5 10:20:58 localhost kernel: [241597.193024]  ef848340 ea0f4a20 f29bbecc c0535332 c05354c0 f5801300 000000d0 4611c000
Jun  5 10:20:58 localhost kernel: [241597.193024]  e7addfe0 ea2124e0 ea37a7e0 f29bbee8 c05354c0 000000d0 00000000 ea37a7e0
Jun  5 10:20:58 localhost kernel: [241597.193024]  ea21253c ea37a83c f29bbf28 c044aca3 ea37af10 ea2478bc f5094abc ea37a9d0
Jun  5 10:20:58 localhost kernel: [241597.193024] Call Trace:
Jun  5 10:20:58 localhost kernel: [241597.193024]  [<c0535332>] ? anon_vma_clone+0x82/0x110
Jun  5 10:20:58 localhost kernel: [241597.193024]  [<c05354c0>] ? anon_vma_fork+0x60/0xf0
Jun  5 10:20:58 localhost kernel: [241597.193024]  [<c05354c0>] anon_vma_fork+0x60/0xf0
Jun  5 10:20:58 localhost kernel: [241597.193024]  [<c044aca3>] dup_mm+0x273/0x4d0
Jun  5 10:20:58 localhost kernel: [241597.193024]  [<c044be8a>] copy_process.part.34+0xf5a/0x1060
Jun  5 10:20:58 localhost kernel: [241597.193024]  [<c044c065>] do_fork+0x95/0x310
Jun  5 10:20:58 localhost kernel: [241597.193024]  [<c04c053e>] ? __audit_syscall_exit+0x1ce/0x260
Jun  5 10:20:58 localhost kernel: [241597.193024]  [<c044c3a5>] sys_clone+0x25/0x30
Jun  5 10:20:58 localhost kernel: [241597.193024]  [<c099a6cd>] sysenter_do_call+0x12/0x28
Jun  5 10:20:58 localhost kernel: [241597.193024] Code: 75 ab 44 00 3e 8d 74 26 00 8b 7d e8 8b 07 64 03 05 54 20 d0 c0 8b 48 04 8b 10 85 d2 89 55 f0 0f 84 06 01 00 00 8b 75 f0 8b 47 14 <8b> 1c 06 8b 37 f7 c6 07 00 00 00 0f 85 2d 01 00 00 8d 41 01 89
Jun  5 10:20:58 localhost kernel: [241597.193024] EIP: [<c0547642>] kmem_cache_alloc+0x52/0x1c0 SS:ESP 0068:f29bbea0
Jun  5 10:20:58 localhost kernel: [241597.193024] CR2: 000000004611c000
Jun  5 10:20:58 localhost kernel: [241597.312140] ---[ end trace a99b690a74c75916 ]---

There were subsequent Oopses after this one.

This system is a:
model name      : Intel(R) Atom(TM) CPU N270   @ 1.60GHz
dual core

# free  (after reboot, just for total mem info)
             total       used       free     shared    buffers     cached
Mem:       1015120     997192      17928          0      16532     844772
-/+ buffers/cache:     135888     879232
Swap:      2129916          0    2129916

And I can't say about how was memory usage. Graphical environment (MATE) was up & logged in, but without any heavy app opened.

# lspci
00:00.0 Host bridge: Intel Corporation Mobile 945GSE Express Memory Controller Hub (rev 03)
00:02.0 VGA compatible controller: Intel Corporation Mobile 945GSE Express Integrated Graphics Controller (rev 03)
00:02.1 Display controller: Intel Corporation Mobile 945GM/GMS/GME, 943/940GML Express Integrated Graphics Controller (rev 03)
00:1b.0 Audio device: Intel Corporation NM10/ICH7 Family High Definition Audio Controller (rev 02)
00:1c.0 PCI bridge: Intel Corporation NM10/ICH7 Family PCI Express Port 1 (rev 02)
00:1c.2 PCI bridge: Intel Corporation NM10/ICH7 Family PCI Express Port 3 (rev 02)
00:1d.0 USB controller: Intel Corporation NM10/ICH7 Family USB UHCI Controller #1 (rev 02)
00:1d.1 USB controller: Intel Corporation NM10/ICH7 Family USB UHCI Controller #2 (rev 02)
00:1d.2 USB controller: Intel Corporation NM10/ICH7 Family USB UHCI Controller #3 (rev 02)
00:1d.3 USB controller: Intel Corporation NM10/ICH7 Family USB UHCI Controller #4 (rev 02)
00:1d.7 USB controller: Intel Corporation NM10/ICH7 Family USB2 EHCI Controller (rev 02)
00:1e.0 PCI bridge: Intel Corporation 82801 Mobile PCI Bridge (rev e2)
00:1f.0 ISA bridge: Intel Corporation 82801GBM (ICH7-M) LPC Interface Bridge (rev 02)
00:1f.2 IDE interface: Intel Corporation 82801GBM/GHM (ICH7-M Family) SATA Controller [IDE mode] (rev 02)
01:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8101E/RTL8102E PCI Express Fast Ethernet controller (rev 02)
02:00.0 Network controller: Realtek Semiconductor Co., Ltd. RTL8187SE Wireless LAN Controller (rev 22)

Wireless has some modules loaded but was not being used.

This happened once, in a full week uptime. F19 is installed on it no longer than that.

Let me know if you need more info. Thanks.