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-rw-r--r--include/linux/sched.h2
-rw-r--r--kernel/trace/ftrace.c13
-rw-r--r--kernel/trace/ring_buffer.c10
-rw-r--r--kernel/trace/trace.h15
4 files changed, 33 insertions, 7 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h
index d8b2d0b..7b78d9c 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1513,7 +1513,7 @@ struct task_struct {
#ifdef CONFIG_TRACING
/* state flags for use by tracers */
unsigned long trace;
- /* bitmask of trace recursion */
+ /* bitmask and counter of trace recursion */
unsigned long trace_recursion;
#endif /* CONFIG_TRACING */
#ifdef CONFIG_CGROUP_MEM_RES_CTLR /* memcg uses this to do batch job */
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 25949b3..1ee417f 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -109,12 +109,18 @@ ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip);
static void ftrace_global_list_func(unsigned long ip,
unsigned long parent_ip)
{
- struct ftrace_ops *op = rcu_dereference_raw(ftrace_global_list); /*see above*/
+ struct ftrace_ops *op;
+
+ if (unlikely(trace_recursion_test(TRACE_GLOBAL_BIT)))
+ return;
+ trace_recursion_set(TRACE_GLOBAL_BIT);
+ op = rcu_dereference_raw(ftrace_global_list); /*see above*/
while (op != &ftrace_list_end) {
op->func(ip, parent_ip);
op = rcu_dereference_raw(op->next); /*see above*/
};
+ trace_recursion_clear(TRACE_GLOBAL_BIT);
}
static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip)
@@ -3490,6 +3496,10 @@ ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip)
{
struct ftrace_ops *op;
+ if (unlikely(trace_recursion_test(TRACE_INTERNAL_BIT)))
+ return;
+
+ trace_recursion_set(TRACE_INTERNAL_BIT);
/*
* Some of the ops may be dynamically allocated,
* they must be freed after a synchronize_sched().
@@ -3502,6 +3512,7 @@ ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip)
op = rcu_dereference_raw(op->next);
};
preempt_enable_notrace();
+ trace_recursion_clear(TRACE_INTERNAL_BIT);
}
static void clear_ftrace_swapper(void)
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 0ef7b4b..b0c7aa4 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -2216,7 +2216,7 @@ static noinline void trace_recursive_fail(void)
printk_once(KERN_WARNING "Tracing recursion: depth[%ld]:"
"HC[%lu]:SC[%lu]:NMI[%lu]\n",
- current->trace_recursion,
+ trace_recursion_buffer(),
hardirq_count() >> HARDIRQ_SHIFT,
softirq_count() >> SOFTIRQ_SHIFT,
in_nmi());
@@ -2226,9 +2226,9 @@ static noinline void trace_recursive_fail(void)
static inline int trace_recursive_lock(void)
{
- current->trace_recursion++;
+ trace_recursion_inc();
- if (likely(current->trace_recursion < TRACE_RECURSIVE_DEPTH))
+ if (likely(trace_recursion_buffer() < TRACE_RECURSIVE_DEPTH))
return 0;
trace_recursive_fail();
@@ -2238,9 +2238,9 @@ static inline int trace_recursive_lock(void)
static inline void trace_recursive_unlock(void)
{
- WARN_ON_ONCE(!current->trace_recursion);
+ WARN_ON_ONCE(!trace_recursion_buffer());
- current->trace_recursion--;
+ trace_recursion_dec();
}
#else
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 6b69c4b..229f859 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -784,4 +784,19 @@ extern const char *__stop___trace_bprintk_fmt[];
FTRACE_ENTRY(call, struct_name, id, PARAMS(tstruct), PARAMS(print))
#include "trace_entries.h"
+/* Only current can touch trace_recursion */
+#define trace_recursion_inc() do { (current)->trace_recursion++; } while (0)
+#define trace_recursion_dec() do { (current)->trace_recursion--; } while (0)
+
+/* Ring buffer has the 10 LSB bits to count */
+#define trace_recursion_buffer() ((current)->trace_recursion & 0x3ff)
+
+/* for function tracing recursion */
+#define TRACE_INTERNAL_BIT (1<<11)
+#define TRACE_GLOBAL_BIT (1<<12)
+
+#define trace_recursion_set(bit) do { (current)->trace_recursion |= (bit); } while (0)
+#define trace_recursion_clear(bit) do { (current)->trace_recursion &= ~(bit); } while (0)
+#define trace_recursion_test(bit) ((current)->trace_recursion & (bit))
+
#endif /* _LINUX_KERNEL_TRACE_H */
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