v0.5.19

Added

• The kselftest boot test runs test_core and test_cpuset of the cgroup selftests. tools/kselftest/build.sh builds them with cgroup/lib/cgroup_util.c, and the init script of the test mounts cgroup2 at /sys/fs/cgroup with nsdelegate, as systemd mounts it (#536).
• The kselftest boot test runs test_freezer and test_kill of the cgroup selftests (#536).
• A TPM 2.0 driver, rk-drv-tpm, as drivers/char/tpm of Linux. On x86-64 the kernel reads the address of the CRB from the ACPI TPM2 table, and on arm64 it finds the FIFO (TIS) interface at the device tree node with compatible = "tcg,tpm-tis-mmio", also on a bus with ranges. The CRB driver uses the locality, the ready and idle requests, the start and cancel registers and the command and response buffers. The TIS driver uses the locality, the status, the burst count and the data FIFO. Each step waits up to the TCG time limits, and each command up to its duration of Linux. At boot the driver starts the TPM as tpm2_auto_startup of Linux. The new tpm boot test gives the machine a swtpm, and the kernel sends TPM2_Startup, TPM2_GetRandom and TPM2_PCR_Read on x86-64 and on arm64 (#541).

Fixed

• A thread that a signal or a tracer stopped, or that waits for its vfork child, counts as frozen in its cgroup, as cgroup_enter_frozen in do_signal_stop, ptrace_stop and wait_for_vfork_done of Linux. A thread that moves to another cgroup in such a wait moves its count. A stop of the group or a request of PTRACE_INTERRUPT ends the wait in the freezer, and the thread takes the stop, as JOBCTL_PENDING_MASK ends the freezer trap of Linux. Before, a freeze of a cgroup with a stopped, traced or vfork thread did not end, and test_freezer of the cgroup kselftests failed (#536).
• A change of cgroup.events and of the other files with events of cgroup2 sends IN_MODIFY to the inotify marks of the file, as kernfs_notify of Linux. A write of cgroup.freeze in a cgroup that a cgroup above it keeps frozen also tells an event, as cgroup_freeze of Linux, so that a reader does not wait for a change that does not come (#536).
• The scheduler does not call the notice function of rk-cgroup, because that function now sends inotify events, which must not run in the scheduler. As kernfs_notify of Linux defers its work, a change of a file with events that comes from a CPU charge waits for the next call outside the scheduler (#536).
• /proc/PID/task/TID/cgroup shows the cgroup of the thread TID, as proc_cgroup_show of Linux. In a threaded subtree, a thread can be in another cgroup than its process. Before, the file showed the cgroup of the process, and test_cgcore_thread_migration failed (#536).