The bug manifests as a soft lockup in kswapd: [ 155.759084] netconsole: network logging started [ 598.920430] BUG: soft lockup - CPU#1 stuck for 67s! [kswapd0:46] [ 598.920472] Modules linked in: netconsole configfs fuse sunrpc cpufreq_ondemand acpi_cpufreq freq_table mperf ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 ip6table_filter ip6_tables snd_hda_codec_hdmi snd_hda_codec_conexant snd_hda_intel snd_hda_codec snd_hwdep arc4 snd_seq snd_seq_device snd_pcm iwlagn mac80211 snd_timer uvcvideo btusb bluetooth snd cfg80211 videodev soundcore v4l2_compat_ioctl32 iTCO_wdt xhci_hcd e1000e snd_page_alloc rfkill i2c_i801 wmi iTCO_vendor_support microcode pcspkr joydev uinput ipv6 sdhci_pci sdhci mmc_core i915 drm_kms_helper drm i2c_algo_bit i2c_core video [last unloaded: netconsole] [ 598.920834] CPU 1 [ 598.920843] Modules linked in: netconsole configfs fuse sunrpc cpufreq_ondemand acpi_cpufreq freq_table mperf ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 ip6table_filter ip6_tables snd_hda_codec_hdmi snd_hda_codec_conexant snd_hda_intel snd_hda_codec snd_hwdep arc4 snd_seq snd_seq_device snd_pcm iwlagn mac80211 snd_timer uvcvideo btusb bluetooth snd cfg80211 videodev soundcore v4l2_compat_ioctl32 iTCO_wdt xhci_hcd e1000e snd_page_alloc rfkill i2c_i801 wmi iTCO_vendor_support microcode pcspkr joydev uinput ipv6 sdhci_pci sdhci mmc_core i915 drm_kms_helper drm i2c_algo_bit i2c_core video [last unloaded: netconsole] [ 598.926818] [ 598.928043] Pid: 46, comm: kswapd0 Not tainted 2.6.39-rc4+ #1 LENOVO 4170CTO/4170CTO [ 598.929299] RIP: 0010:[<ffffffffa007ff9b>] [<ffffffffa007ff9b>] i915_gem_inactive_shrink+0x78/0x194 [i915] [ 598.930603] RSP: 0018:ffff8800709ebd50 EFLAGS: 00000216 [ 598.931867] RAX: ffff88006ec5c6b0 RBX: 00000000000000c0 RCX: 0000000000000000 [ 598.933135] RDX: ffff880037e59638 RSI: 0000000000000000 RDI: ffff880037876020 [ 598.934408] RBP: ffff8800709ebd90 R08: 0000000000000000 R09: 000000000001bd90 [ 598.935680] R10: 0000000000000002 R11: ffffffff81a44e50 R12: ffffffff8148300e [ 598.936944] R13: ffff8800709ebcf0 R14: ffff8800709ebcf8 R15: ffffffff810dd64d [ 598.938221] FS: 0000000000000000(0000) GS:ffff880100240000(0000) knlGS:0000000000000000 [ 598.939525] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b [ 598.940813] CR2: 00007fe16a34d380 CR3: 0000000001a03000 CR4: 00000000000406e0 [ 598.942114] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 598.943441] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 [ 598.944744] Process kswapd0 (pid: 46, threadinfo ffff8800709ea000, task ffff88006df8ae00) [ 598.946044] Stack: [ 598.947317] ffff8800709ebd90 ffff880037e59638 ffff8800709ebd60 ffff880037e595f0 [ 598.948654] 0000000000000000 0000000000000000 00000000000000d0 000000000004c24e [ 598.949986] ffff8800709ebde0 ffffffff810e1f89 000000000000003d 0000000000000080 [ 598.951329] Call Trace: [ 598.952673] [<ffffffff810e1f89>] shrink_slab+0x6d/0x166 [ 598.954003] [<ffffffff810e4bcc>] kswapd+0x533/0x798 [ 598.955331] [<ffffffff810e4699>] ? mem_cgroup_shrink_node_zone+0xe3/0xe3 [ 598.956683] [<ffffffff8106e157>] kthread+0x84/0x8c [ 598.958022] [<ffffffff81483764>] kernel_thread_helper+0x4/0x10 [ 598.959379] [<ffffffff8106e0d3>] ? kthread_worker_fn+0x148/0x148 [ 598.960709] [<ffffffff81483760>] ? gs_change+0x13/0x13 [ 598.962032] Code: 31 ed 48 83 c3 48 48 2d b0 00 00 00 eb 0a 48 8d 82 50 ff ff ff 41 ff c5 48 8b 90 b0 00 00 00 48 05 b0 00 00 00 48 39 d8 0f 18 0a [ 598.962192] e1 e9 da 00 00 00 4c 89 f7 e8 c6 fd ff ff 48 8b 43 48 4c 8b [ 598.965009] Call Trace: [ 598.966421] [<ffffffff810e1f89>] shrink_slab+0x6d/0x166 [ 598.966423] [<ffffffff810e4bcc>] kswapd+0x533/0x798 [ 598.966426] [<ffffffff810e4699>] ? mem_cgroup_shrink_node_zone+0xe3/0xe3 [ 598.966429] [<ffffffff8106e157>] kthread+0x84/0x8c [ 598.966432] [<ffffffff81483764>] kernel_thread_helper+0x4/0x10 [ 598.966435] [<ffffffff8106e0d3>] ? kthread_worker_fn+0x148/0x148 [ 598.966438] [<ffffffff81483760>] ? gs_change+0x13/0x13 The traces are slightly different each reboot cycle, but it's always in kswapd and usually in shrink_slab. Once it happens, anything that touches the filesystem hangs in D wait, so the machine is basically toast. The box is a Lenovo T420s sandybridge core i5 based laptop with 2GB of memory. There is a corresponding Red Hat bugzilla report here: https://bugzilla.redhat.com/show_bug.cgi?id=694818 And I've verified that the bug also shows in the 2.6.38.3 stable kernel. If anyone wants me to try anything, please let me know. James -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>