# strange lockups and rsync

## albright

I have been experiencing irregular lockups requiring forced

reboot for some time now.

The only common feature seems to be that they happen while snapback2

is running (an rsync based backup script).

This is very nebulous but I wonder if anyone has some insight. Is this

hardware related (on last error I got a bios error to the effect that

"overclocking failed" but I am not overclocking so ... but then it rebooted

fine.) Or what ?

Here's is the latest error:

```
May 17 17:08:53 gandalf kernel: BUG: unable to handle kernel NULL pointer dereference at 0000000000000018

May 17 17:08:53 gandalf kernel: IP: gen8_ppgtt_alloc_page_directories.isra.36+0x11d/0x260 [i915]

May 17 17:08:53 gandalf kernel: PGD 423235067 

May 17 17:08:53 gandalf kernel: PUD 42327a067 

May 17 17:08:53 gandalf kernel: PMD 0 

May 17 17:08:53 gandalf kernel: 

May 17 17:08:53 gandalf kernel: Oops: 0002 [#1] PREEMPT SMP

May 17 17:08:53 gandalf kernel: Modules linked in: nfnetlink_queue vmnet(O) vmblock(O) vsock vmmon(O) vmci(O) ipt_MASQUERADE nf_nat_masquerade_ipv4 xt_recent xt_comment iptable_nat nf_nat_ipv4 ipt_REJECT nf_reject_ipv4 xt_addrtype xt_mark iptable_mangle xt_helper xt_tcpudp iptable_raw xt_multiport nf_conntrack_ipv4 nf_defrag_ipv4 xt_conntrack xt_NFLOG nfnetlink_log xt_LOG nf_log_ipv4 nf_log_common nf_nat_tftp nf_nat_snmp_basic nf_conntrack_snmp nf_nat_sip nf_nat_pptp nf_nat_proto_gre nf_nat_irc nf_nat_h323 nf_nat_ftp nf_nat_amanda ts_kmp nf_conntrack_amanda nf_nat nf_conntrack_sane nf_conntrack_tftp nf_conntrack_sip nf_conntrack_pptp nf_conntrack_proto_gre nf_conntrack_netlink nfnetlink nf_conntrack_netbios_ns nf_conntrack_broadcast nf_conntrack_irc nf_conntrack_h323 nf_conntrack_ftp nf_conntrack iptable_filter ip_tables

May 17 17:08:53 gandalf kernel:  x_tables snd_hda_codec_hdmi usblp snd_hda_codec_realtek snd_hda_codec_generic nct6775 hwmon_vid uhci_hcd snd_hda_intel snd_hda_codec snd_hwdep snd_hda_core e1000e snd_pcm x86_pkg_temp_thermal snd_timer ptp snd r8169 coretemp ehci_pci pps_core ehci_hcd soundcore mii i915 i2c_algo_bit drm_kms_helper intel_lpss_acpi syscopyarea intel_lpss sysfillrect sysimgblt fb_sys_fops drm intel_gtt agpgart xhci_pci xhci_hcd tpm_tis tpm_tis_core tpm

May 17 17:08:53 gandalf kernel: CPU: 6 PID: 25805 Comm: X Tainted: G           O    4.10.13-gentoo #1

May 17 17:08:53 gandalf kernel: Hardware name: System manufacturer System Product Name/Z170-K, BIOS 1803 05/06/2016

May 17 17:08:53 gandalf kernel: task: ffff880310de0000 task.stack: ffffc90002e94000

May 17 17:08:53 gandalf kernel: RIP: 0010:gen8_ppgtt_alloc_page_directories.isra.36+0x11d/0x260 [i915]

May 17 17:08:53 gandalf kernel: RSP: 0018:ffffc90002e97900 EFLAGS: 00010286

May 17 17:08:53 gandalf kernel: RAX: ffff880113924000 RBX: 0000000000004000 RCX: ffff8803d6c99000

May 17 17:08:53 gandalf kernel: RDX: 0000000000000000 RSI: ffff8803d6c98000 RDI: ffff8804200a8000

May 17 17:08:53 gandalf kernel: RBP: ffffc90002e97958 R08: 0000000000000000 R09: 0000000000000000

May 17 17:08:53 gandalf kernel: R10: 0000160000000000 R11: 0000000000000000 R12: ffff880405ba6000

May 17 17:08:53 gandalf kernel: R13: 0000000000000003 R14: 0000000000000003 R15: 00000000ff9fb000

May 17 17:08:53 gandalf kernel: FS:  00007f1dc0c248c0(0000) GS:ffff880436d80000(0000) knlGS:0000000000000000

May 17 17:08:53 gandalf kernel: CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033

May 17 17:08:53 gandalf kernel: CR2: 0000000000000018 CR3: 00000001ed2f4000 CR4: 00000000003406e0

May 17 17:08:53 gandalf kernel: DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000

May 17 17:08:53 gandalf kernel: DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

May 17 17:08:53 gandalf kernel: Call Trace:

May 17 17:08:53 gandalf kernel:  gen8_alloc_va_range_3lvl+0xc8/0x9f0 [i915]

May 17 17:08:53 gandalf kernel:  ? shmem_getpage_gfp+0xbc/0xad0

May 17 17:08:53 gandalf kernel:  ? swiotlb_map_sg_attrs+0x53/0x120

May 17 17:08:53 gandalf kernel:  gen8_alloc_va_range+0x248/0x4a0 [i915]

May 17 17:08:53 gandalf kernel:  i915_vma_bind+0x65/0x1a0 [i915]

May 17 17:08:53 gandalf kernel:  __i915_vma_do_pin+0x2d8/0x4e0 [i915]

May 17 17:08:53 gandalf kernel:  i915_gem_execbuffer_reserve_vma.isra.29+0x13f/0x1a0 [i915]

May 17 17:08:53 gandalf kernel:  i915_gem_execbuffer_reserve.isra.30+0x36d/0x390 [i915]

May 17 17:08:53 gandalf kernel:  i915_gem_do_execbuffer.isra.36+0x651/0x1570 [i915]

May 17 17:08:53 gandalf kernel:  ? i915_gem_object_get_sg+0xf5/0x200 [i915]

May 17 17:08:53 gandalf kernel:  ? i915_gem_object_get_page+0x11/0x40 [i915]

May 17 17:08:53 gandalf kernel:  ? i915_gem_pwrite_ioctl+0x4b7/0x6e0 [i915]

May 17 17:08:53 gandalf kernel:  i915_gem_execbuffer2+0xa3/0x220 [i915]

May 17 17:08:53 gandalf kernel:  drm_ioctl+0x205/0x450 [drm]

May 17 17:08:53 gandalf kernel:  ? i915_gem_execbuffer+0x2e0/0x2e0 [i915]

May 17 17:08:53 gandalf kernel:  ? __fget+0x72/0xa0

May 17 17:08:53 gandalf kernel:  do_vfs_ioctl+0x8b/0x5a0

May 17 17:08:53 gandalf kernel:  ? __fget+0x72/0xa0

May 17 17:08:53 gandalf kernel:  SyS_ioctl+0x3c/0x70

May 17 17:08:53 gandalf kernel:  entry_SYSCALL_64_fastpath+0x1a/0xa9

May 17 17:08:53 gandalf kernel: RIP: 0033:0x7f1dbeb10b67

May 17 17:08:53 gandalf kernel: RSP: 002b:00007fff17288a28 EFLAGS: 00003246 ORIG_RAX: 0000000000000010

May 17 17:08:53 gandalf kernel: RAX: ffffffffffffffda RBX: 0000000000fe78d0 RCX: 00007f1dbeb10b67

May 17 17:08:53 gandalf kernel: RDX: 00007fff17288a80 RSI: 00000000c0406469 RDI: 0000000000000015

May 17 17:08:53 gandalf kernel: RBP: 0000000000fda130 R08: 0000000000000000 R09: 00000000ffffffff

May 17 17:08:53 gandalf kernel: R10: 0000000000000070 R11: 0000000000003246 R12: 0000000000000000

May 17 17:08:53 gandalf kernel: R13: 0000000000fda7d0 R14: 0000000001475ca0 R15: 0000000000fe7950

May 17 17:08:53 gandalf kernel: Code: 20 03 00 00 48 89 c6 48 89 45 c0 49 8b bc 24 d8 02 00 00 48 8b 52 08 48 83 ca 03 e8 4e e0 ff ff 48 8b 45 b0 48 8b 10 48 8b 45 c0 <4a> 89 04 ea 48 8b 45 d0 4c 0f ab 28 0f 1f 44 00 00 e9 60 ff ff 

May 17 17:08:53 gandalf kernel: RIP: gen8_ppgtt_alloc_page_directories.isra.36+0x11d/0x260 [i915] RSP: ffffc90002e97900

May 17 17:08:53 gandalf kernel: CR2: 0000000000000018

May 17 17:08:53 gandalf kernel: ---[ end trace afc8375816b4a6f8 ]---

```

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## khayyam

albright ...

it seems to be this i915 bug (and probably triggered in your case by the additional load produced by rsync). There is a backport for 4.11 you might try.

HTH & best ... khay

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## albright

As an update, it happened again yesterday, once again during

the rsync backup (snapback2), but this time the error involved

kswapd (no swap file space was ever used by the way during

the incident)

the error (notice the last line, after traceback):

```
Jun  6 17:38:14 gandalf kernel: BUG: unable to handle kernel NULL pointer dereference at 0000000000000030

Jun  6 17:38:14 gandalf kernel: IP: iput+0xfe/0x220

Jun  6 17:38:14 gandalf kernel: PGD 0 

Jun  6 17:38:14 gandalf kernel: 

Jun  6 17:38:14 gandalf kernel: Oops: 0000 [#1] PREEMPT SMP

Jun  6 17:38:14 gandalf kernel: Modules linked in: vmnet(O) vmblock(O) vmmon(O) vsock vmci(O) ipt_MASQUERADE nf_nat_masquerade_ipv4 xt_recent xt_comment iptable_nat nf_nat_ipv4 ipt_REJECT nf_reject_ipv4 xt_addrtype xt_mark iptable_mangle xt_helper xt_tcpudp iptable_raw xt_multiport nf_conntrack_ipv4 nf_defrag_ipv4 xt_conntrack xt_NFLOG nfnetlink_log xt_LOG nf_log_ipv4 nf_log_common nf_nat_tftp nf_nat_snmp_basic nf_conntrack_snmp nf_nat_sip nf_nat_pptp nf_nat_proto_gre nf_nat_irc nf_nat_h323 nf_nat_ftp nf_nat_amanda ts_kmp nf_conntrack_amanda nf_nat nf_conntrack_sane nf_conntrack_tftp nf_conntrack_sip nf_conntrack_pptp nf_conntrack_proto_gre nf_conntrack_netlink nfnetlink nf_conntrack_netbios_ns nf_conntrack_broadcast nf_conntrack_irc nf_conntrack_h323 nf_conntrack_ftp nf_conntrack iptable_filter ip_tables x_tables usblp

Jun  6 17:38:14 gandalf kernel:  snd_hda_codec_hdmi snd_hda_codec_realtek snd_hda_codec_generic nct6775 hwmon_vid uhci_hcd snd_hda_intel snd_hda_codec snd_hwdep snd_hda_core x86_pkg_temp_thermal snd_pcm coretemp snd_timer e1000e snd r8169 ehci_pci ehci_hcd ptp soundcore mii pps_core i915 intel_lpss_acpi intel_lpss i2c_algo_bit drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops drm intel_gtt agpgart xhci_pci xhci_hcd tpm_tis tpm_tis_core tpm

Jun  6 17:38:14 gandalf kernel: CPU: 1 PID: 68 Comm: kswapd0 Tainted: G           O    4.11.3-gentoo #1

Jun  6 17:38:14 gandalf kernel: Hardware name: System manufacturer System Product Name/Z170-K, BIOS 1803 05/06/2016

Jun  6 17:38:14 gandalf kernel: task: ffff880424b9d000 task.stack: ffffc900002b0000

Jun  6 17:38:14 gandalf kernel: RIP: 0010:iput+0xfe/0x220

Jun  6 17:38:14 gandalf kernel: RSP: 0018:ffffc900002b3c08 EFLAGS: 00010246

Jun  6 17:38:14 gandalf kernel: RAX: 0000000000000100 RBX: 0000000000000000 RCX: 0000000000000001

Jun  6 17:38:14 gandalf kernel: RDX: 00000000005f3ee4 RSI: ffff880020c74068 RDI: ffff880020c74068

Jun  6 17:38:14 gandalf kernel: RBP: ffffc900002b3c28 R08: ffffc900002b3db0 R09: 0000000000000000

Jun  6 17:38:14 gandalf kernel: R10: 000000000020e6cb R11: 0000000000000000 R12: ffff880020c73fe8

Jun  6 17:38:14 gandalf kernel: R13: ffff880020c74128 R14: ffff880020c74068 R15: ffff8803480d1c80

Jun  6 17:38:14 gandalf kernel: FS:  0000000000000000(0000) GS:ffff880436c40000(0000) knlGS:0000000000000000

Jun  6 17:38:14 gandalf kernel: CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033

Jun  6 17:38:14 gandalf kernel: CR2: 0000000000000030 CR3: 0000000001a17000 CR4: 00000000003406e0

Jun  6 17:38:14 gandalf kernel: DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000

Jun  6 17:38:14 gandalf kernel: DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

Jun  6 17:38:14 gandalf kernel: Call Trace:

Jun  6 17:38:14 gandalf kernel:  dentry_unlink_inode+0xf8/0x130

Jun  6 17:38:14 gandalf kernel:  __dentry_kill+0xbb/0x160

Jun  6 17:38:14 gandalf kernel:  shrink_dentry_list+0x11f/0x2f0

Jun  6 17:38:14 gandalf kernel:  prune_dcache_sb+0x46/0x60

Jun  6 17:38:14 gandalf kernel:  super_cache_scan+0x10f/0x1a0

Jun  6 17:38:14 gandalf kernel:  shrink_slab.part.66.constprop.79+0x1c9/0x3c0

Jun  6 17:38:14 gandalf kernel:  shrink_node+0x60/0x180

Jun  6 17:38:14 gandalf kernel:  kswapd+0x337/0x6a0

Jun  6 17:38:14 gandalf kernel:  kthread+0x103/0x140

Jun  6 17:38:14 gandalf kernel:  ? try_to_free_pages+0x410/0x410

Jun  6 17:38:14 gandalf kernel:  ? kthread_create_on_node+0x40/0x40

Jun  6 17:38:14 gandalf kernel:  ret_from_fork+0x2c/0x40

Jun  6 17:38:14 gandalf kernel: Code: 08 48 83 c3 18 4c 89 e6 ff d0 48 8b 03 48 85 c0 75 eb 65 ff 0d 6c eb e6 7e 74 02 eb 8d e8 e3 28 e6 ff eb 86 49 8b 5c 24 28 a8 08 <4c> 8b 6b 30 0f 85 ba 00 00 00 49 8b 45 20 48 85 c0 74 4f 4c 89 

Jun  6 17:38:14 gandalf kernel: RIP: iput+0xfe/0x220 RSP: ffffc900002b3c08

Jun  6 17:38:14 gandalf kernel: CR2: 0000000000000030

Jun  6 17:38:14 gandalf kernel: ---[ end trace 60cc857d27842c28 ]---

Jun  6 17:38:14 gandalf kernel: note: kswapd0[68] exited with preempt_count 1

```

[Moderator edit: changed [quote] tags to [code] tags to preserve output layout. -Hu]

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