releases/4.19.34/kprobes-prohibit-probing-on-rcu-debug-routine.patch

   1 From 1b52b6a49493e417e58e8aea1eb3bb2554738b3c Mon Sep 17 00:00:00 2001
   2 From: Masami Hiramatsu <mhiramat@kernel.org>
   3 Date: Wed, 13 Feb 2019 01:14:37 +0900
   4 Subject: kprobes: Prohibit probing on RCU debug routine
   5
   6 [ Upstream commit a39f15b9644fac3f950f522c39e667c3af25c588 ]
   7
   8 Since kprobe itself depends on RCU, probing on RCU debug
   9 routine can cause recursive breakpoint bugs.
  10
  11 Prohibit probing on RCU debug routines.
  12
  13 int3
  14  ->do_int3()
  15    ->ist_enter()
  16      ->RCU_LOCKDEP_WARN()
  17        ->debug_lockdep_rcu_enabled() -> int3
  18
  19 Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
  20 Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
  21 Cc: Andrea Righi <righi.andrea@gmail.com>
  22 Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
  23 Cc: Jiri Olsa <jolsa@redhat.com>
  24 Cc: Linus Torvalds <torvalds@linux-foundation.org>
  25 Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  26 Cc: Peter Zijlstra <peterz@infradead.org>
  27 Cc: Steven Rostedt <rostedt@goodmis.org>
  28 Cc: Thomas Gleixner <tglx@linutronix.de>
  29 Link: http://lkml.kernel.org/r/154998807741.31052.11229157537816341591.stgit@devbox
  30 Signed-off-by: Ingo Molnar <mingo@kernel.org>
  31 Signed-off-by: Sasha Levin <sashal@kernel.org>
  32 ---
  33  kernel/rcu/update.c | 2 ++
  34  1 file changed, 2 insertions(+)
  35
  36 diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c
  37 index 39cb23d22109..81688a133552 100644
  38 --- a/kernel/rcu/update.c
  39 +++ b/kernel/rcu/update.c
  40 @@ -52,6 +52,7 @@
  41  #include <linux/tick.h>
  42  #include <linux/rcupdate_wait.h>
  43  #include <linux/sched/isolation.h>
  44 +#include <linux/kprobes.h>
  45
  46  #define CREATE_TRACE_POINTS
  47
  48 @@ -253,6 +254,7 @@ int notrace debug_lockdep_rcu_enabled(void)
  49                current->lockdep_recursion == 0;
  50  }
  51  EXPORT_SYMBOL_GPL(debug_lockdep_rcu_enabled);
  52 +NOKPROBE_SYMBOL(debug_lockdep_rcu_enabled);
  53
  54  /**
  55   * rcu_read_lock_held() - might we be in RCU read-side critical section?
  56 --
  57 2.19.1
  58