Commit 984640ce authored Feb 13, 2019 by Masami Hiramatsu Committed by Ingo Molnar Feb 13, 2019

kprobes: Prohibit probing on preemption checking debug functions



Since kprobes depends on preempt disable/enable, probing
on the preempt debug routines can cause recursive breakpoint
bugs.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andrea Righi <righi.andrea@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/154998804911.31052.3541963527929117920.stgit@devbox


Signed-off-by: Ingo Molnar <mingo@kernel.org>

parent eeeb080b

lib/smp_processor_id.c

+5 −2

Original line number	Diff line number	Diff line
		@@ -5,10 +5,11 @@
		* DEBUG_PREEMPT variant of smp_processor_id().
		*/
		#include <linux/export.h>
		#include <linux/kprobes.h>
		#include <linux/sched.h>

		notrace static unsigned int check_preemption_disabled(const char *what1,
		const char *what2)
		notrace static nokprobe_inline
		unsigned int check_preemption_disabled(const char what1, const char what2)
		{
		int this_cpu = raw_smp_processor_id();

		@@ -56,9 +57,11 @@ notrace unsigned int debug_smp_processor_id(void)
		return check_preemption_disabled("smp_processor_id", "");
		}
		EXPORT_SYMBOL(debug_smp_processor_id);
		NOKPROBE_SYMBOL(debug_smp_processor_id);

		notrace void __this_cpu_preempt_check(const char *op)
		{
		check_preemption_disabled("__this_cpu_", op);
		}
		EXPORT_SYMBOL(__this_cpu_preempt_check);
		NOKPROBE_SYMBOL(__this_cpu_preempt_check);

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