Xorg crashed with signal 7 in dl_new_hash()

[Sosha]

after turn on system(on suspend mode) and login session...

ProblemType: Crash
DistroRelease: Ubuntu 18.04
Package: xserver-xorg-core 2:1.19.6-1ubuntu3
ProcVersionSignature: Ubuntu 4.15.0-12.13-generic 4.15.7
Uname: Linux 4.15.0-12-generic x86_64
NonfreeKernelModules: nvidia_modeset nvidia
.proc.driver.nvidia.gpus.0000.01.00.0: Error: [Errno 21] Is a directory: '/proc/driver/nvidia/gpus/0000:01:00.0'
.proc.driver.nvidia.registry: Binary: ""
.proc.driver.nvidia.version:
 NVRM version: NVIDIA UNIX x86_64 Kernel Module 390.42 Sat Mar 3 04:10:22 PST 2018
 GCC version: gcc version 7.3.0 (Ubuntu 7.3.0-11ubuntu1)
.proc.driver.nvidia.warnings.fbdev:
 Your system is not currently configured to drive a VGA console
 on the primary VGA device. The NVIDIA Linux graphics driver
 requires the use of a text-mode VGA console. Use of other console
 drivers including, but not limited to, vesafb, may result in
 corruption and stability problems, and is not supported.
ApportVersion: 2.20.8-0ubuntu10
Architecture: amd64
CompizPlugins: No value set for `/apps/compiz-1/general/screen0/options/active_plugins'
CompositorRunning: None
CrashCounter: 1
Date: Mon Mar 19 22:53:41 2018
DistUpgraded: Fresh install
DistroCodename: bionic
DistroVariant: ubuntu
DkmsStatus:
 nvidia, 390.42, 4.15.0-12-generic, x86_64: installed
 virtualbox, 5.2.8, 4.15.0-12-generic, x86_64: installed
ExecutablePath: /usr/lib/xorg/Xorg
GraphicsCard:
 NVIDIA Corporation GP107 [GeForce GTX 1050 Ti] [10de:1c82] (rev a1) (prog-if 00 [VGA controller])
   Subsystem: ASUSTeK Computer Inc. GP107 [GeForce GTX 1050 Ti] [1043:85cd]
InstallationDate: Installed on 2017-09-02 (198 days ago)
InstallationMedia: Ubuntu-GNOME 17.04 "Zesty Zapus" - Release amd64 (20170412)
MachineType: System manufacturer System Product Name
ProcCmdline: /usr/lib/xorg/Xorg vt2 -displayfd 3 -auth /run/user/1000/gdm/Xauthority -background none -noreset -keeptty -verbose 3
ProcEnviron:

ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.15.0-12-generic.efi.signed root=UUID=a5d262b4-1b0f-4856-9935-f6a7f6d6d406 ro quiet splash vt.handoff=1
Signal: 7
SourcePackage: nvidia-graphics-drivers
StacktraceTop:
 dl_new_hash (s=0x7f1d94fa7f3c "pixman_rasterize_trapezoid") at dl-lookup.c:555
 _dl_lookup_symbol_x (undef_name=0x7f1d94fa7f3c "pixman_rasterize_trapezoid", undef_map=0x55a6c8f6d5b0, ref=ref@entry=0x7ffeda6e5728, symbol_scope=0x55a6c8f6d908, version=0x0, type_class=type_class@entry=1, flags=5, skip_map=0x0) at dl-lookup.c:791
 _dl_fixup (l=<optimized out>, reloc_arg=<optimized out>) at ../elf/dl-runtime.c:112
 _dl_runtime_resolve_xsavec () at ../sysdeps/x86_64/dl-trampoline.h:125
 wfbRasterizeTrapezoid () from /usr/lib/xorg/modules/libwfb.so
Title: Xorg crashed with signal 7 in dl_new_hash()
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm cdrom dip libvirt lpadmin plugdev sambashare sudo
dmi.bios.date: 09/19/2016
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 2003
dmi.board.asset.tag: Default string
dmi.board.name: Z170-P
dmi.board.vendor: ASUSTeK COMPUTER INC.
dmi.board.version: Rev X.0x
dmi.chassis.asset.tag: Default string
dmi.chassis.type: 3
dmi.chassis.vendor: Default string
dmi.chassis.version: Default string
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr2003:bd09/19/2016:svnSystemmanufacturer:pnSystemProductName:pvrSystemVersion:rvnASUSTeKCOMPUTERINC.:rnZ170-P:rvrRevX.0x:cvnDefaultstring:ct3:cvrDefaultstring:
dmi.product.family: To be filled by O.E.M.
dmi.product.name: System Product Name
dmi.product.version: System Version
dmi.sys.vendor: System manufacturer
version.compiz: compiz N/A
version.libdrm2: libdrm2 2.4.90-1
version.libgl1-mesa-dri: libgl1-mesa-dri 18.0.0~rc4-1ubuntu3
version.libgl1-mesa-glx: libgl1-mesa-glx 18.0.0~rc4-1ubuntu3
version.nvidia-graphics-drivers: nvidia-graphics-drivers-* N/A
version.xserver-xorg-core: xserver-xorg-core 2:1.19.6-1ubuntu3
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev N/A
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:7.10.0-1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.917+git20171229-1
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.15-2

[Apport retracing service (apport)]

StacktraceTop:
 dl_new_hash (s=0x7f1d94fa7f3c "pixman_rasterize_trapezoid") at dl-lookup.c:555
 _dl_lookup_symbol_x (undef_name=0x7f1d94fa7f3c "pixman_rasterize_trapezoid", undef_map=0x55a6c8f6d5b0, ref=ref@entry=0x7ffeda6e5728, symbol_scope=0x55a6c8f6d908, version=0x0, type_class=type_class@entry=1, flags=5, skip_map=0x0) at dl-lookup.c:791
 _dl_fixup (l=<optimized out>, reloc_arg=<optimized out>) at ../elf/dl-runtime.c:112
 _dl_runtime_resolve_xsavec () at ../sysdeps/x86_64/dl-trampoline.h:125
 wfbRasterizeTrapezoid (pPicture=0x55a6c977fa80, trap=0x55a6c9c11ce4, x_off=0, y_off=0) at ../../../../fb/fbtrap.c:60

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Alan Jenkins (aj504)]

I strongly suspect this is the same bug in upstream kernel v4.15, which causes this issue:

https://bugs.launchpad.net/ubuntu/+source/xorg-server/+bug/1760450/comments/6

I am basing this on the "signal 7" (SIGBUS), as this is relatively rare on x86 [1]. Also that it occurs inside xorg_backtrace() - this is also *supposed* to be relatively rare, because libunwind tries to use a clever trick to avoid reading wild pointers and dying with a segmentation fault [2].

[1] https://stackoverflow.com/questions/2089167/debugging-sigbus-on-x86-linux
[2] https://lwn.net/Articles/502864/

I would also predict that the original fault was caused by fetching the first instruction of the function, but it looks like we don't have the symbol information for it. (boo, nvidia).