Commit 77a7f2e9 authored by Ingo Molnar's avatar Ingo Molnar
Browse files

Merge branch 'tracing/core' of... 

Merge branch 'tracing/core' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/random-tracing into tracing/core
parents ac0053fd cecbca96

Documentation/kernel-parameters.txt

+5 −1
Original line number Diff line number Diff line
@@ -784,8 +784,12 @@ and is between 256 and 4096 characters. It is defined in the file 
			as early as possible in order to facilitate early

			boot debugging.



	ftrace_dump_on_oops

	ftrace_dump_on_oops[=orig_cpu]

			[FTRACE] will dump the trace buffers on oops.

			If no parameter is passed, ftrace will dump

			buffers of all CPUs, but if you pass orig_cpu, it will

			dump only the buffer of the CPU that triggered the

			oops.



	ftrace_filter=[function-list]

			[FTRACE] Limit the functions traced by the function

Documentation/trace/ftrace.txt

+4 −2
Original line number Diff line number Diff line
@@ -1337,12 +1337,14 @@ ftrace_dump_on_oops must be set. To set ftrace_dump_on_oops, one 
can either use the sysctl function or set it via the proc system

interface.



  sysctl kernel.ftrace_dump_on_oops=1

  sysctl kernel.ftrace_dump_on_oops=n



or



  echo 1 > /proc/sys/kernel/ftrace_dump_on_oops

  echo n > /proc/sys/kernel/ftrace_dump_on_oops



If n = 1, ftrace will dump buffers of all CPUs, if n = 2 ftrace will

only dump the buffer of the CPU that triggered the oops.



Here's an example of such a dump after a null pointer

dereference in a kernel module:

drivers/char/sysrq.c

+1 −1
Original line number Diff line number Diff line
@@ -289,7 +289,7 @@ static struct sysrq_key_op sysrq_showstate_blocked_op = { 


static void sysrq_ftrace_dump(int key, struct tty_struct *tty)

{

	ftrace_dump();

	ftrace_dump(DUMP_ALL);

}

static struct sysrq_key_op sysrq_ftrace_dump_op = {

	.handler	= sysrq_ftrace_dump,

include/linux/ftrace.h

+3 −1
Original line number Diff line number Diff line
@@ -492,7 +492,9 @@ static inline int test_tsk_trace_graph(struct task_struct *tsk) 
	return tsk->trace & TSK_TRACE_FL_GRAPH;

}



extern int ftrace_dump_on_oops;

enum ftrace_dump_mode;



extern enum ftrace_dump_mode ftrace_dump_on_oops;



#ifdef CONFIG_PREEMPT

#define INIT_TRACE_RECURSION		.trace_recursion = 0,

include/linux/kernel.h

+9 −2
Original line number Diff line number Diff line
@@ -490,6 +490,13 @@ static inline void tracing_off(void) { } 
static inline void tracing_off_permanent(void) { }

static inline int tracing_is_on(void) { return 0; }

#endif



enum ftrace_dump_mode {

	DUMP_NONE,

	DUMP_ALL,

	DUMP_ORIG,

};



#ifdef CONFIG_TRACING

extern void tracing_start(void);

extern void tracing_stop(void);
@@ -571,7 +578,7 @@ __ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap); 
extern int

__ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap);



extern void ftrace_dump(void);

extern void ftrace_dump(enum ftrace_dump_mode oops_dump_mode);

#else

static inline void

ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3) { }
@@ -592,7 +599,7 @@ ftrace_vprintk(const char *fmt, va_list ap) 
{

	return 0;

}

static inline void ftrace_dump(void) { }

static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { }

#endif /* CONFIG_TRACING */



/*