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authorMasami Hiramatsu <mhiramat@kernel.org>2017-10-20 08:43:39 +0900
committerIngo Molnar <mingo@kernel.org>2017-10-20 09:45:15 +0200
commita30b85df7d599f626973e9cd3056fe755bd778e0 (patch)
tree55a48cb0090bcf658c53affd7d740708e4678f43 /arch
parentRevert "kprobes: Warn if optprobe handler tries to change execution path" (diff)
downloadlinux-dev-a30b85df7d599f626973e9cd3056fe755bd778e0.tar.xz
linux-dev-a30b85df7d599f626973e9cd3056fe755bd778e0.zip
kprobes: Use synchronize_rcu_tasks() for optprobe with CONFIG_PREEMPT=y
We want to wait for all potentially preempted kprobes trampoline execution to have completed. This guarantees that any freed trampoline memory is not in use by any task in the system anymore. synchronize_rcu_tasks() gives such a guarantee, so use it. Also, this guarantees to wait for all potentially preempted tasks on the instructions which will be replaced with a jump. Since this becomes a problem only when CONFIG_PREEMPT=y, enable CONFIG_TASKS_RCU=y for synchronize_rcu_tasks() in that case. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Naveen N . Rao <naveen.n.rao@linux.vnet.ibm.com> Cc: Paul E . McKenney <paulmck@linux.vnet.ibm.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/150845661962.5443.17724352636247312231.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to '')
-rw-r--r--arch/Kconfig2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/Kconfig b/arch/Kconfig
index 1aafb4efbb51..f75c8e8a229b 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -90,7 +90,7 @@ config STATIC_KEYS_SELFTEST
config OPTPROBES
def_bool y
depends on KPROBES && HAVE_OPTPROBES
- depends on !PREEMPT
+ select TASKS_RCU if PREEMPT
config KPROBES_ON_FTRACE
def_bool y