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-rw-r--r--include/linux/context_tracking_state.h1
-rw-r--r--kernel/context_tracking.c29
2 files changed, 30 insertions, 0 deletions
diff --git a/include/linux/context_tracking_state.h b/include/linux/context_tracking_state.h
index 6b7b96a32b75..678ecdf90cf6 100644
--- a/include/linux/context_tracking_state.h
+++ b/include/linux/context_tracking_state.h
@@ -12,6 +12,7 @@ struct context_tracking {
* may be further optimized using static keys.
*/
bool active;
+ int recursion;
enum ctx_state {
CONTEXT_KERNEL = 0,
CONTEXT_USER,
diff --git a/kernel/context_tracking.c b/kernel/context_tracking.c
index 72d59a1a6eb6..5b11a10e196a 100644
--- a/kernel/context_tracking.c
+++ b/kernel/context_tracking.c
@@ -38,6 +38,25 @@ void context_tracking_cpu_set(int cpu)
}
}
+static bool context_tracking_recursion_enter(void)
+{
+ int recursion;
+
+ recursion = __this_cpu_inc_return(context_tracking.recursion);
+ if (recursion == 1)
+ return true;
+
+ WARN_ONCE((recursion < 1), "Invalid context tracking recursion value %d\n", recursion);
+ __this_cpu_dec(context_tracking.recursion);
+
+ return false;
+}
+
+static void context_tracking_recursion_exit(void)
+{
+ __this_cpu_dec(context_tracking.recursion);
+}
+
/**
* context_tracking_enter - Inform the context tracking that the CPU is going
* enter user or guest space mode.
@@ -75,6 +94,9 @@ void context_tracking_enter(enum ctx_state state)
WARN_ON_ONCE(!current->mm);
local_irq_save(flags);
+ if (!context_tracking_recursion_enter())
+ goto out_irq_restore;
+
if ( __this_cpu_read(context_tracking.state) != state) {
if (__this_cpu_read(context_tracking.active)) {
/*
@@ -105,6 +127,8 @@ void context_tracking_enter(enum ctx_state state)
*/
__this_cpu_write(context_tracking.state, state);
}
+ context_tracking_recursion_exit();
+out_irq_restore:
local_irq_restore(flags);
}
NOKPROBE_SYMBOL(context_tracking_enter);
@@ -139,6 +163,9 @@ void context_tracking_exit(enum ctx_state state)
return;
local_irq_save(flags);
+ if (!context_tracking_recursion_enter())
+ goto out_irq_restore;
+
if (__this_cpu_read(context_tracking.state) == state) {
if (__this_cpu_read(context_tracking.active)) {
/*
@@ -153,6 +180,8 @@ void context_tracking_exit(enum ctx_state state)
}
__this_cpu_write(context_tracking.state, CONTEXT_KERNEL);
}
+ context_tracking_recursion_exit();
+out_irq_restore:
local_irq_restore(flags);
}
NOKPROBE_SYMBOL(context_tracking_exit);