This bug is awaiting verification that the kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed- focal' to 'verification-done-focal'. If the problem still exists, change the tag 'verification-needed-focal' to 'verification-failed-focal'.
If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you! ** Tags added: verification-needed-focal -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1888332 Title: [Potential Regression] dscr_inherit_exec_test from powerpc in ubuntu_kernel_selftests failed on B/E/F Status in linux package in Ubuntu: Invalid Status in linux source package in Bionic: Fix Committed Status in linux source package in Eoan: Won't Fix Status in linux source package in Focal: Fix Committed Bug description: [Impact] Code that touches DSCR user MSR does not set dscr_inherit, which breaks DSCR restore doing context switches and inheritance when forking. DSCR is used to control cache hinting. This is caused by lack of kernel interrupt when the DSCR user MSR is written, which is controlled by FSCR which would otherwise cause a facility unavailable interrupt. [Test case] apt-get source linux cd linux-5.4.0/tools/testing/tools/selftests/powerpc/ make -j 32 make -C dscr run_tests make -C ptrace run_tests make -C tm run_tests Look up for "not ok" versus "ok", specially for dscr_inherit_exec_test, ptrace-tar and tm-resched-tar. [Potential regression] Manipulating DSCR might break on different machines (with DTs containing /cpus/ibm,powerpc-cpu-features, for example). Code that does so might crash because the facility unavailable interrupt handling might be not working correctly. ==================================== Issue found on 5.3.0-64.58 with P8 node modoc (passed with P9 node) # selftests: powerpc/dscr: dscr_inherit_exec_test # test: dscr_inherit_exec_test # tags: git_version:unknown # Parent DSCR 1 was not inherited over exec (kernel value) # Child didn't exit cleanly # failure: dscr_inherit_exec_test not ok 5 selftests: powerpc/dscr: dscr_inherit_exec_test # exit=1 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1888332/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
