Merge tag 'trace-v4.19-1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace (452938cb) · Commits · 戴 / test

Pull tracing fixes from Steven Rostedt: "Masami found an off by one bug in the code that keeps "notrace" functions from being traced by kprobes. During my testing, I found that there's places that we may want to add kprobes to notrace, thus we may end up changing this code before 4.19 is released. The history behind this change is that we found that adding kprobes to various notrace functions caused the kernel to crashed. We took the safe route and decided not to allow kprobes to trace any notrace function. But because notrace is added to functions that just cause weird side effects to the function tracer, but are still safe, preventing kprobes for all notrace functios may be too much of a big hammer. One such place is __schedule() is marked notrace, to keep function tracer from doing strange recursive loops when it gets traced with NEED_RESCHED set. With this change, one can not add kprobes to the scheduler. Masami also added code to use gcov on ftrace" * tag 'trace-v4.19-1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: tracing/kprobes: Fix to check notrace function with correct range tracing: Allow gcov profiling on only ftrace subsystem

kernel/trace/Kconfig

+12 −0

Original line number	Diff line number	Diff line
		@@ -774,6 +774,18 @@ config TRACING_EVENTS_GPIO
		help
		Enable tracing events for gpio subsystem

		config GCOV_PROFILE_FTRACE
		bool "Enable GCOV profiling on ftrace subsystem"
		depends on GCOV_KERNEL
		help
		Enable GCOV profiling on ftrace subsystem for checking
		which functions/lines are tested.

		If unsure, say N.

		Note that on a kernel compiled with this config, ftrace will
		run significantly slower.

		endif # FTRACE

		endif # TRACING_SUPPORT

kernel/trace/Makefile

+5 −0

Original line number	Diff line number	Diff line
		@@ -23,6 +23,11 @@ ifdef CONFIG_TRACING_BRANCHES
		KBUILD_CFLAGS += -DDISABLE_BRANCH_PROFILING
		endif

		# for GCOV coverage profiling
		ifdef CONFIG_GCOV_PROFILE_FTRACE
		GCOV_PROFILE := y
		endif

		CFLAGS_trace_benchmark.o := -I$(src)
		CFLAGS_trace_events_filter.o := -I$(src)

kernel/trace/trace_kprobe.c

+8 −1

Original line number	Diff line number	Diff line
		@@ -513,7 +513,14 @@ static bool within_notrace_func(struct trace_kprobe *tk)
		if (!addr \|\| !kallsyms_lookup_size_offset(addr, &size, &offset))
		return false;

		return !ftrace_location_range(addr - offset, addr - offset + size);
		/* Get the entry address of the target function */
		addr -= offset;

		/*
		* Since ftrace_location_range() does inclusive range check, we need
		* to subtract 1 byte from the end address.
		*/
		return !ftrace_location_range(addr, addr + size - 1);
		}
		#else
		#define within_notrace_func(tk) (false)

Admin message