dmesg | grep error and journalctl -xe what's output what was last thing you did before this problem occured could you give more details because we won't be able to help without more details

when i do dmesg |grep error and journalctl -xe nothing is happening. But when i do dmesg |grep failed i have this error. i see it when i look on dmesg but there is non visible bug. i paste a part of dmesg log.

Apr 28 20:16:13 darqawa kernel: [ 0.831431] integrity: Loading X.509 certificate: UEFI:db
Apr 28 20:16:13 darqawa kernel: [ 0.831449] integrity: Loaded X.509 cert 'Microsoft Windows Production PCA 2011: a92902398e16c49778cd90f99e4f9ae17c55af53'
Apr 28 20:16:13 darqawa kernel: [ 0.831450] integrity: Loading X.509 certificate: UEFI:db
Apr 28 20:16:13 darqawa kernel: [ 0.831466] integrity: Loaded X.509 cert 'Microsoft Corporation UEFI CA 2011: 13adbf4309bd82709c8cd54f316ed522988a1bd4'
Apr 28 20:16:13 darqawa kernel: [ 0.832777] Freeing unused kernel image (initmem) memory: 2388K
Apr 28 20:16:13 darqawa kernel: [ 0.860096] Write protecting the kernel read-only data: 22528k
Apr 28 20:16:13 darqawa kernel: [ 0.860508] Freeing unused kernel image (text/rodata gap) memory: 2040K
Apr 28 20:16:13 darqawa kernel: [ 0.860610] Freeing unused kernel image (rodata/data gap) memory: 644K
Apr 28 20:16:13 darqawa kernel: [ 0.902619] x86/mm: Checked W+X mappings: passed, no W+X pages found.
Apr 28 20:16:13 darqawa kernel: [ 0.902620] x86/mm: Checking user space page tables
Apr 28 20:16:13 darqawa kernel: [ 0.941882] x86/mm: Checked W+X mappings: passed, no W+X pages found.
Apr 28 20:16:13 darqawa kernel: [ 0.941886] Run /init as init process
Apr 28 20:16:13 darqawa kernel: [ 1.043006] video: module verification failed: signature and/or required key missing - tainting kernel
Apr 28 20:16:13 darqawa kernel: [ 1.052096] wmi_bus wmi_bus-PNP0C14:00: WQBC data block query control method not found

try this https://stackoverflow.com/questions/24975377/kvm-module-verification-failed-signature-and-or-required-key-missing-taintin