Panic with drm-next on Thinkpad T460s (Skylake, Intel HD Graphics 520) when undocking from Lenovo docking station

[raw-bin]

Hi.

I experience this panic frequently when undocking my Thinkpad T460s from it's Lenovo docking station. Prior to the undock I was using xrandr to get video output to an external monitor connected to the dock.

Relevant details are as under.

1. Links to pics showing the panic and the backtrace:

• This is a link to a pic showing the panic log.

• This is a link to a pic showing the backtrace.

  2. Output of uname -a: FreeBSD gene 12.0-CURRENT FreeBSD 12.0-CURRENT #2 ff9c7fc1f1a(drm-next)-dirty: Fri Jul 14 21:29:44 BST 2017 robin@gene:/usr/obj/usr/src/sys/GENERIC amd64

  3. The kernel is drm-next as of yesterday built with the bog standard GENERIC configuration. The dirty indication is because I have the following patch in place which was needed in order for suspend-resume to work correctly as reported here:

diff --git a/sys/modules/drm/i915/i915kmsfw/skldmc/Makefile b/sys/modules/drm/i915/i915kmsfw/skldmc/Makefile
index d6c389c24d8..c066a25daae 100644
--- a/sys/modules/drm/i915/i915kmsfw/skldmc/Makefile
+++ b/sys/modules/drm/i915/i915kmsfw/skldmc/Makefile
@@ -1,7 +1,7 @@
 # $FreeBSD$

-KMOD   = i915_skl_dmc_ver1_26_bin
-NAME   = i915/skl_dmc_ver1_26.bin
-IMG    = skl_dmc_ver1_26
+KMOD   = i915_skl_dmc_ver1_bin
+NAME   = i915/skl_dmc_ver1.bin
+IMG    = skl_dmc_ver1

 .include <bsd.kmod.mk>
diff --git a/sys/modules/drm/i915/i915kmsfw/sklguc/Makefile b/sys/modules/drm/i915/i915kmsfw/sklguc/Makefile
index 509b6e2b795..b787d2d9540 100644
--- a/sys/modules/drm/i915/i915kmsfw/sklguc/Makefile
+++ b/sys/modules/drm/i915/i915kmsfw/sklguc/Makefile
@@ -1,6 +1,6 @@
 # $FreeBSD$

-KMOD   = i915_skl_guc_ver6_1_bin
-NAME   = i915/skl_guc_ver6_1.bin
-IMG    = skl_guc_ver6_1
+KMOD   = i915_skl_guc_ver4_bin
+NAME   = i915/skl_guc_ver4.bin
+IMG    = skl_guc_ver4
 .include <bsd.kmod.mk>

4. rc.conf contents

clear_tmp_enable="YES"
sendmail_enable="NONE"
hostname="gene"
keymap="uk.capsctrl.kbd"
ifconfig_em0="DHCP"
sshd_enable="YES"
ntpd_enable="YES"
powerd_enable="YES"
powerd_flags="-a hiadaptive -b adaptive -i 75 -r 85 -p 500"
performance_cx_lowest="Cmax"
economy_cx_lowest="Cmax"
# Set dumpdev to "AUTO" to enable crash dumps, "NO" to disable
dumpdev="AUTO"
zfs_enable="YES"
kld_list="i915kms"
dbus_enable="YES"
hald_enable="YES"
#slim_enable="YES"
gdm_enable="YES"
gnome_enable="YES"
webcamd_enable="YES"
wlans_iwm0="wlan0"
ifconfig_wlan0="WPA SYNCDHCP"
linux_enable="YES"

5. loader.conf contents

kern.geom.label.disk_ident.enable="0"
kern.geom.label.gptid.enable="0"
zfs_load="YES"
cuse_load="YES"
if_iwm_load="YES"
iwm8000Cfw_load="YES"
hw.pci.do_power_nodriver=3
drm.i915.enable_rc6=7
hw.snd.latency=7
hint.pcm.0.buffersize=65536
hint.pcm.1.buffersize=65536
hint.pcm.2.buffersize=65536
hw.snd.feeder_buffersize=65536
kern.vty=vt
fusefs_load="YES"

6. Output of pciconf -lv:

hostb0@pci0:0:0:0:      class=0x060000 card=0x223317aa chip=0x19048086 rev=0x08 hdr=0x00
    vendor     = 'Intel Corporation'
    device     = 'Skylake Host Bridge/DRAM Registers'
    class      = bridge
    subclass   = HOST-PCI
vgapci0@pci0:0:2:0:     class=0x030000 card=0x223317aa chip=0x19168086 rev=0x07 hdr=0x00
    vendor     = 'Intel Corporation'
    device     = 'HD Graphics 520'
    class      = display
    subclass   = VGA
none0@pci0:0:8:0:       class=0x088000 card=0x223317aa chip=0x19118086 rev=0x00 hdr=0x00
    vendor     = 'Intel Corporation'
    device     = 'Skylake Gaussian Mixture Model'
    class      = base peripheral
xhci0@pci0:0:20:0:      class=0x0c0330 card=0x223317aa chip=0x9d2f8086 rev=0x21 hdr=0x00
    vendor     = 'Intel Corporation'
    device     = 'Sunrise Point-LP USB 3.0 xHCI Controller'
    class      = serial bus
    subclass   = USB
none1@pci0:0:20:2:      class=0x118000 card=0x223317aa chip=0x9d318086 rev=0x21 hdr=0x00
    vendor     = 'Intel Corporation'
    device     = 'Sunrise Point-LP Thermal subsystem'
    class      = dasp
none2@pci0:0:22:0:      class=0x078000 card=0x223317aa chip=0x9d3a8086 rev=0x21 hdr=0x00
    vendor     = 'Intel Corporation'
    device     = 'Sunrise Point-LP CSME HECI'
    class      = simple comms
none3@pci0:0:22:3:      class=0x070002 card=0x223317aa chip=0x9d3d8086 rev=0x21 hdr=0x00
    vendor     = 'Intel Corporation'
    class      = simple comms
    subclass   = UART
ahci0@pci0:0:23:0:      class=0x010601 card=0x223317aa chip=0x9d038086 rev=0x21 hdr=0x00
    vendor     = 'Intel Corporation'
    device     = 'Sunrise Point-LP SATA Controller [AHCI mode]'
    class      = mass storage
    subclass   = SATA
pcib1@pci0:0:28:0:      class=0x060400 card=0x223317aa chip=0x9d108086 rev=0xf1 hdr=0x01
    vendor     = 'Intel Corporation'
    class      = bridge
    subclass   = PCI-PCI
pcib2@pci0:0:28:2:      class=0x060400 card=0x223317aa chip=0x9d128086 rev=0xf1 hdr=0x01
    vendor     = 'Intel Corporation'
    class      = bridge
    subclass   = PCI-PCI
isab0@pci0:0:31:0:      class=0x060100 card=0x223317aa chip=0x9d488086 rev=0x21 hdr=0x00
    vendor     = 'Intel Corporation'
    device     = 'Sunrise Point-LP LPC Controller'
    class      = bridge
    subclass   = PCI-ISA
none4@pci0:0:31:2:      class=0x058000 card=0x223317aa chip=0x9d218086 rev=0x21 hdr=0x00
    vendor     = 'Intel Corporation'
    device     = 'Sunrise Point-LP PMC'
    class      = memory
hdac0@pci0:0:31:3:      class=0x040300 card=0x223317aa chip=0x9d708086 rev=0x21 hdr=0x00
    vendor     = 'Intel Corporation'
    device     = 'Sunrise Point-LP HD Audio'
    class      = multimedia
    subclass   = HDA
none5@pci0:0:31:4:      class=0x0c0500 card=0x223317aa chip=0x9d238086 rev=0x21 hdr=0x00
    vendor     = 'Intel Corporation'
    device     = 'Sunrise Point-LP SMBus'
    class      = serial bus
    subclass   = SMBus
em0@pci0:0:31:6:        class=0x020000 card=0x223317aa chip=0x156f8086 rev=0x21 hdr=0x00
    vendor     = 'Intel Corporation'
    device     = 'Ethernet Connection I219-LM'
    class      = network
    subclass   = ethernet
none6@pci0:2:0:0:       class=0xff0000 card=0x223317aa chip=0x522a10ec rev=0x01 hdr=0x00
    vendor     = 'Realtek Semiconductor Co., Ltd.'
    device     = 'RTS522A PCI Express Card Reader'
iwm0@pci0:4:0:0:        class=0x028000 card=0x01308086 chip=0x24f38086 rev=0x3a hdr=0x00
    vendor     = 'Intel Corporation'
    device     = 'Wireless 8260'
    class      = network

Please let me know if any other details would help. Any help/guidance graciously appreciated.

Cheers.

[raw-bin]

There's this code from pfs_add_node() at sys/fs/pseudofs/pseudofs.c:108:

#ifdef INVARIANTS
    /* XXX no locking! */
    if (pn->pn_type == pfstype_procdir)
        for (iter = parent; iter != NULL; iter = iter->pn_parent)
            KASSERT(iter->pn_type != pfstype_procdir,
                ("%s(): nested process directories", __func__));

I wonder whether that has a bearing on the problem ? The GENERIC conf enables INVARIANTS.

[valpackett]

You can try GENERIC-NODEBUG to avoid assertion panics. Of course they should be actually fixed though…

[raw-bin]

@myfreeweb Thanks. I commented out the code block referenced above and haven't had panics any more. Agree that a proper fix is preferable. I'll keep this open for the moment.