[tip:perf/core] kprobes: Prohibit probing on preemption checking debug functions

tip-bot for Masami Hiramatsu
2019-02-13T09:03:22Z

Commit-ID: 984640ce427fa67c7c1f8550ab53495733bd11fc
Gitweb: https://git.kernel.org/tip/984640ce427fa67c7c1f8550ab53495733bd11fc
Author: Masami Hiramatsu <mhiramat@kernel.org>
AuthorDate: Wed, 13 Feb 2019 01:14:09 +0900
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Wed, 13 Feb 2019 08:16:40 +0100

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>
---
lib/smp_processor_id.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/lib/smp_processor_id.c b/lib/smp_processor_id.c
index 85925aaa4fff..157d9e31f6c2 100644
--- a/lib/smp_processor_id.c
+++ b/lib/smp_processor_id.c
@@ -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);