Description of problem:
Due to non-availability of Hyper-V video driver hyperv_fb in kdump
initramfs, the console seems to be in hang state with no text over it.
Version-Release number of selected component (if applicable):
kexec-tools-2.0.15-16.el7.x86_64
How reproducible:
100%
Steps to Reproduce:
1. Start os
2. Add "crashkernel=auto" to kernel parameter and reboot
3. Start kdump service and check kdump is running
# kdumpctl status
Kdump is operational
4. Check the kdump initramfs does not include hyperv_fb
# lsinitrd /boot/initramfs-3.10.0-915.el7.x86_64kdump.img | grep hyperv_fb
5. Trigger the crash and check the console
# echo c > /proc/sysrq-trigger
Actual results:
After kernel crash, the console seems to be in hang state with no text
over it until reboot
Expected results:
The logs will be visible over console after crash
Additional info:
If add hyperv_fb in kdump initramfs, the logs will be visible over console
1) Ensure /etc/kdump.conf contains the following line :
extra_modules hyperv_fb
2) Restart kdump service and check the kdump initramfs including the
hyperv_fb module
# lsinitrd /boot/initramfs-3.10.0-915.el7.x86_64kdump.img | grep hyperv_fb
Arguments: --hostonly --hostonly-cmdline --hostonly-i18n -o 'plymouth
dash resume ifcfg' --mount '/dev/mapper/rhel_bootp--73--131--181-root
/sysroot xfs defaults' --add-drivers ' hyperv_fb'
--no-hostonly-default-device -f
-rw-r--r-- 1 root root 6636 Jun 22 20:09
usr/lib/modules/3.10.0-915.el7.x86_64/kernel/drivers/video/hyperv_fb.ko.xz
3) Trigger the crash and check the console, check logs will be visible
over console
# echo c > /proc/sysrq-trigger
Refer to https://access.redhat.com/solutions/3500231 and
https://bugzilla.redhat.com/show_bug.cgi?id=1228774
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.
For information on the advisory, and where to find the updated
files, follow the link below.
If the solution does not work for you, open a new bug report.
https://access.redhat.com/errata/RHBA-2018:3240