android_kernel_motorola_sm6375/Documentation/trace
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Filename Latest commit message Latest commit date
Miroslav Benes 93d31322f7
UPSTREAM: ftrace: Introduce PERMANENT ftrace_ops flag
Livepatch uses ftrace for redirection to new patched functions. It means
that if ftrace is disabled, all live patched functions are disabled as
well. Toggling global 'ftrace_enabled' sysctl thus affect it directly.
It is not a problem per se, because only administrator can set sysctl
values, but it still may be surprising.

Introduce PERMANENT ftrace_ops flag to amend this. If the
FTRACE_OPS_FL_PERMANENT is set on any ftrace ops, the tracing cannot be
disabled by disabling ftrace_enabled. Equally, a callback with the flag
set cannot be registered if ftrace_enabled is disabled.

Link: http://lkml.kernel.org/r/20191016113316.13415-2-mbenes@suse.cz

Reviewed-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Change-Id: I78f8241bb5b63fe020a33131604ff447620c3a95
Signed-off-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2025-12-23 13:35:45 -08:00
..
postprocess
coresight-cpu-debug.rst
coresight.rst
events-kmem.rst
events-msr.rst
events-nmi.rst
events-power.rst
events.rst
ftrace-design.rst
ftrace-uses.rst
ftrace.rst
function-graph-fold.vim
histogram.rst
hwlat_detector.rst
index.rst
intel_th.rst
kprobetrace.rst
mmiotrace.rst
ring-buffer-design.txt
stm.rst
sys-t.rst
tracepoint-analysis.rst
tracepoints.rst
uprobetracer.rst