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cpuidle: tracing: Warn about !rcu_is_watching() 

When using noinstr, WARN when tracing hits when RCU is disabled.

Suggested-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20230126151323.466670589@infradead.org
This commit is contained in:
Peter Zijlstra 2023-01-26 16:08:32 +01:00 committed by Ingo Molnar
parent 5a5d7e9bad
commit d099dbfd33
1 changed files with 18 additions and 0 deletions
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18
include/linux/trace_recursion.h
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@ -135,6 +135,21 @@ extern void ftrace_record_recursion(unsigned long ip, unsigned long parent_ip);
# define do_ftrace_record_recursion(ip, pip) do { } while (0)
#endif
#ifdef CONFIG_ARCH_WANTS_NO_INSTR
# define trace_warn_on_no_rcu(ip) \
({ \
bool __ret = !rcu_is_watching(); \
if (__ret && !trace_recursion_test(TRACE_RECORD_RECURSION_BIT)) { \
trace_recursion_set(TRACE_RECORD_RECURSION_BIT); \
WARN_ONCE(true, "RCU not on for: %pS\n", (void *)ip); \
trace_recursion_clear(TRACE_RECORD_RECURSION_BIT); \
} \
__ret; \
})
#else
# define trace_warn_on_no_rcu(ip) false
#endif
/*
* Preemption is promised to be disabled when return bit >= 0.
*/
@ -144,6 +159,9 @@ static __always_inline int trace_test_and_set_recursion(unsigned long ip, unsign
unsigned int val = READ_ONCE(current->trace_recursion);
int bit;
if (trace_warn_on_no_rcu(ip))
return -1;
bit = trace_get_context_bit() + start;
if (unlikely(val & (1 << bit))) {
/*