3f5a54e371
At OLS I had a lot of interest to be able to have the ftrace buffers dumped on panic. Usually one would expect to uses kexec and examine the buffers after a new kernel is loaded. But sometimes the resources do not permit kdump and kexec, so having an option to still see the sequence of events up to the crash is very advantageous. This patch adds the option to have the ftrace buffers dumped to the console in the latency_trace format on a panic. When the option is set, the default entries per CPU buffer are lowered to 16384, since the writing to the serial (if that is the console) may take an awful long time otherwise. [ Changes since -v1: Got alpine to send correctly (as well as spell check working). Removed config option. Moved the static variables into ftrace_dump itself. Gave printk a log level. ] Signed-off-by: Steven Rostedt <srostedt@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
206 lines
6.2 KiB
C
206 lines
6.2 KiB
C
#ifndef _LINUX_FTRACE_H
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#define _LINUX_FTRACE_H
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#ifdef CONFIG_FTRACE
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#include <linux/linkage.h>
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#include <linux/fs.h>
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extern int ftrace_enabled;
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extern int
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ftrace_enable_sysctl(struct ctl_table *table, int write,
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struct file *filp, void __user *buffer, size_t *lenp,
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loff_t *ppos);
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typedef void (*ftrace_func_t)(unsigned long ip, unsigned long parent_ip);
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struct ftrace_ops {
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ftrace_func_t func;
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struct ftrace_ops *next;
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};
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/*
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* The ftrace_ops must be a static and should also
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* be read_mostly. These functions do modify read_mostly variables
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* so use them sparely. Never free an ftrace_op or modify the
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* next pointer after it has been registered. Even after unregistering
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* it, the next pointer may still be used internally.
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*/
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int register_ftrace_function(struct ftrace_ops *ops);
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int unregister_ftrace_function(struct ftrace_ops *ops);
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void clear_ftrace_function(void);
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extern void ftrace_stub(unsigned long a0, unsigned long a1);
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#else /* !CONFIG_FTRACE */
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# define register_ftrace_function(ops) do { } while (0)
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# define unregister_ftrace_function(ops) do { } while (0)
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# define clear_ftrace_function(ops) do { } while (0)
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#endif /* CONFIG_FTRACE */
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#ifdef CONFIG_DYNAMIC_FTRACE
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# define FTRACE_HASHBITS 10
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# define FTRACE_HASHSIZE (1<<FTRACE_HASHBITS)
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enum {
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FTRACE_FL_FREE = (1 << 0),
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FTRACE_FL_FAILED = (1 << 1),
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FTRACE_FL_FILTER = (1 << 2),
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FTRACE_FL_ENABLED = (1 << 3),
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FTRACE_FL_NOTRACE = (1 << 4),
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FTRACE_FL_CONVERTED = (1 << 5),
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FTRACE_FL_FROZEN = (1 << 6),
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};
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struct dyn_ftrace {
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struct hlist_node node;
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unsigned long ip; /* address of mcount call-site */
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unsigned long flags;
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};
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int ftrace_force_update(void);
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void ftrace_set_filter(unsigned char *buf, int len, int reset);
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/* defined in arch */
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extern int ftrace_ip_converted(unsigned long ip);
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extern unsigned char *ftrace_nop_replace(void);
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extern unsigned char *ftrace_call_replace(unsigned long ip, unsigned long addr);
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extern int ftrace_dyn_arch_init(void *data);
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extern int ftrace_mcount_set(unsigned long *data);
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extern int ftrace_modify_code(unsigned long ip, unsigned char *old_code,
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unsigned char *new_code);
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extern int ftrace_update_ftrace_func(ftrace_func_t func);
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extern void ftrace_caller(void);
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extern void ftrace_call(void);
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extern void mcount_call(void);
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extern int skip_trace(unsigned long ip);
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void ftrace_disable_daemon(void);
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void ftrace_enable_daemon(void);
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#else
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# define skip_trace(ip) ({ 0; })
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# define ftrace_force_update() ({ 0; })
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# define ftrace_set_filter(buf, len, reset) do { } while (0)
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# define ftrace_disable_daemon() do { } while (0)
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# define ftrace_enable_daemon() do { } while (0)
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#endif /* CONFIG_DYNAMIC_FTRACE */
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/* totally disable ftrace - can not re-enable after this */
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void ftrace_kill(void);
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void ftrace_kill_atomic(void);
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static inline void tracer_disable(void)
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{
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#ifdef CONFIG_FTRACE
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ftrace_enabled = 0;
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#endif
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}
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/* Ftrace disable/restore without lock. Some synchronization mechanism
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* must be used to prevent ftrace_enabled to be changed between
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* disable/restore. */
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static inline int __ftrace_enabled_save(void)
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{
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#ifdef CONFIG_FTRACE
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int saved_ftrace_enabled = ftrace_enabled;
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ftrace_enabled = 0;
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return saved_ftrace_enabled;
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#else
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return 0;
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#endif
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}
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static inline void __ftrace_enabled_restore(int enabled)
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{
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#ifdef CONFIG_FTRACE
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ftrace_enabled = enabled;
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#endif
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}
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#ifdef CONFIG_FRAME_POINTER
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/* TODO: need to fix this for ARM */
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# define CALLER_ADDR0 ((unsigned long)__builtin_return_address(0))
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# define CALLER_ADDR1 ((unsigned long)__builtin_return_address(1))
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# define CALLER_ADDR2 ((unsigned long)__builtin_return_address(2))
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# define CALLER_ADDR3 ((unsigned long)__builtin_return_address(3))
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# define CALLER_ADDR4 ((unsigned long)__builtin_return_address(4))
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# define CALLER_ADDR5 ((unsigned long)__builtin_return_address(5))
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# define CALLER_ADDR6 ((unsigned long)__builtin_return_address(6))
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#else
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# define CALLER_ADDR0 ((unsigned long)__builtin_return_address(0))
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# define CALLER_ADDR1 0UL
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# define CALLER_ADDR2 0UL
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# define CALLER_ADDR3 0UL
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# define CALLER_ADDR4 0UL
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# define CALLER_ADDR5 0UL
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# define CALLER_ADDR6 0UL
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#endif
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#ifdef CONFIG_IRQSOFF_TRACER
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extern void time_hardirqs_on(unsigned long a0, unsigned long a1);
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extern void time_hardirqs_off(unsigned long a0, unsigned long a1);
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#else
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# define time_hardirqs_on(a0, a1) do { } while (0)
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# define time_hardirqs_off(a0, a1) do { } while (0)
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#endif
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#ifdef CONFIG_PREEMPT_TRACER
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extern void trace_preempt_on(unsigned long a0, unsigned long a1);
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extern void trace_preempt_off(unsigned long a0, unsigned long a1);
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#else
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# define trace_preempt_on(a0, a1) do { } while (0)
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# define trace_preempt_off(a0, a1) do { } while (0)
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#endif
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#ifdef CONFIG_TRACING
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extern void
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ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3);
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/**
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* ftrace_printk - printf formatting in the ftrace buffer
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* @fmt: the printf format for printing
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*
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* Note: __ftrace_printk is an internal function for ftrace_printk and
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* the @ip is passed in via the ftrace_printk macro.
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*
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* This function allows a kernel developer to debug fast path sections
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* that printk is not appropriate for. By scattering in various
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* printk like tracing in the code, a developer can quickly see
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* where problems are occurring.
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*
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* This is intended as a debugging tool for the developer only.
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* Please refrain from leaving ftrace_printks scattered around in
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* your code.
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*/
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# define ftrace_printk(fmt...) __ftrace_printk(_THIS_IP_, fmt)
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extern int
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__ftrace_printk(unsigned long ip, const char *fmt, ...)
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__attribute__ ((format (printf, 2, 3)));
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extern void ftrace_dump(void);
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#else
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static inline void
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ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3) { }
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static inline int
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ftrace_printk(const char *fmt, ...) __attribute__ ((format (printf, 1, 0)))
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{
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return 0;
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}
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static inline void ftrace_dump(void) { }
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#endif
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#ifdef CONFIG_FTRACE_MCOUNT_RECORD
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extern void ftrace_init(void);
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extern void ftrace_init_module(unsigned long *start, unsigned long *end);
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extern void ftrace_release(void *start, unsigned long size);
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#else
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static inline void ftrace_init(void) { }
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static inline void
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ftrace_init_module(unsigned long *start, unsigned long *end) { }
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static inline void ftrace_release(void *start, unsigned long size) { }
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#endif
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#endif /* _LINUX_FTRACE_H */
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