diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index e4cbca58536c9f3ab4236f4db78eb22cacc993af..ab67b33300fb6367926e9b0819c6fec73f442f48 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -789,8 +789,12 @@ 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
diff --git a/Documentation/trace/ftrace.txt b/Documentation/trace/ftrace.txt
index 03485bfbd7975792f50d54dabf77533938f255c9..52011815c905cf835f63c74670c8d14c602a95aa 100644
--- a/Documentation/trace/ftrace.txt
+++ b/Documentation/trace/ftrace.txt
@@ -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:
diff --git a/drivers/char/sysrq.c b/drivers/char/sysrq.c
index 59de2525d3030ac972f48295f1b5191513784790..d4e8b213a46254f34622be1a3026e601e170b463 100644
--- a/drivers/char/sysrq.c
+++ b/drivers/char/sysrq.c
@@ -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,
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 01e6adea07ecf798a0a45331a297e8ea5b481e42..ea5b1aae0e8bab39038ee66f3c9c457f14c3909e 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -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,
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 9365227dbaf6498f4b4318c7205e8e1a61103da5..9fb1c1299032ca8a051d969b8ab2bde46ea707b1 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -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 */
/*
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index bed83cab6da2f06ee57393a633ed4def9fc908ec..7b516c7ef9a00008c810da42dc98dd1c12c6edd4 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -117,9 +117,12 @@ static cpumask_var_t __read_mostly tracing_buffer_mask;
*
* It is default off, but you can enable it with either specifying
* "ftrace_dump_on_oops" in the kernel command line, or setting
- * /proc/sys/kernel/ftrace_dump_on_oops to true.
+ * /proc/sys/kernel/ftrace_dump_on_oops
+ * Set 1 if you want to dump buffers of all CPUs
+ * Set 2 if you want to dump the buffer of the CPU that triggered oops
*/
-int ftrace_dump_on_oops;
+
+enum ftrace_dump_mode ftrace_dump_on_oops;
static int tracing_set_tracer(const char *buf);
@@ -139,8 +142,17 @@ __setup("ftrace=", set_cmdline_ftrace);
static int __init set_ftrace_dump_on_oops(char *str)
{
- ftrace_dump_on_oops = 1;
- return 1;
+ if (*str++ != '=' || !*str) {
+ ftrace_dump_on_oops = DUMP_ALL;
+ return 1;
+ }
+
+ if (!strcmp("orig_cpu", str)) {
+ ftrace_dump_on_oops = DUMP_ORIG;
+ return 1;
+ }
+
+ return 0;
}
__setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops);
@@ -4338,7 +4350,7 @@ static int trace_panic_handler(struct notifier_block *this,
unsigned long event, void *unused)
{
if (ftrace_dump_on_oops)
- ftrace_dump();
+ ftrace_dump(ftrace_dump_on_oops);
return NOTIFY_OK;
}
@@ -4355,7 +4367,7 @@ static int trace_die_handler(struct notifier_block *self,
switch (val) {
case DIE_OOPS:
if (ftrace_dump_on_oops)
- ftrace_dump();
+ ftrace_dump(ftrace_dump_on_oops);
break;
default:
break;
@@ -4396,7 +4408,8 @@ trace_printk_seq(struct trace_seq *s)
trace_seq_init(s);
}
-static void __ftrace_dump(bool disable_tracing)
+static void
+__ftrace_dump(bool disable_tracing, enum ftrace_dump_mode oops_dump_mode)
{
static arch_spinlock_t ftrace_dump_lock =
(arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
@@ -4429,12 +4442,25 @@ static void __ftrace_dump(bool disable_tracing)
/* don't look at user memory in panic mode */
trace_flags &= ~TRACE_ITER_SYM_USEROBJ;
- printk(KERN_TRACE "Dumping ftrace buffer:\n");
-
/* Simulate the iterator */
iter.tr = &global_trace;
iter.trace = current_trace;
- iter.cpu_file = TRACE_PIPE_ALL_CPU;
+
+ switch (oops_dump_mode) {
+ case DUMP_ALL:
+ iter.cpu_file = TRACE_PIPE_ALL_CPU;
+ break;
+ case DUMP_ORIG:
+ iter.cpu_file = raw_smp_processor_id();
+ break;
+ case DUMP_NONE:
+ goto out_enable;
+ default:
+ printk(KERN_TRACE "Bad dumping mode, switching to all CPUs dump\n");
+ iter.cpu_file = TRACE_PIPE_ALL_CPU;
+ }
+
+ printk(KERN_TRACE "Dumping ftrace buffer:\n");
/*
* We need to stop all tracing on all CPUS to read the
@@ -4473,6 +4499,7 @@ static void __ftrace_dump(bool disable_tracing)
else
printk(KERN_TRACE "---------------------------------\n");
+ out_enable:
/* Re-enable tracing if requested */
if (!disable_tracing) {
trace_flags |= old_userobj;
@@ -4489,9 +4516,9 @@ static void __ftrace_dump(bool disable_tracing)
}
/* By default: disable tracing after the dump */
-void ftrace_dump(void)
+void ftrace_dump(enum ftrace_dump_mode oops_dump_mode)
{
- __ftrace_dump(true);
+ __ftrace_dump(true, oops_dump_mode);
}
__init static int tracer_alloc_buffers(void)
diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c
index 9398034f814aa964652acfc6b92f56ee2224144d..6a9d36ddfcf2e7a261da81fcb17930f1651d2daa 100644
--- a/kernel/trace/trace_selftest.c
+++ b/kernel/trace/trace_selftest.c
@@ -256,7 +256,8 @@ trace_selftest_startup_function(struct tracer *trace, struct trace_array *tr)
/* Maximum number of functions to trace before diagnosing a hang */
#define GRAPH_MAX_FUNC_TEST 100000000
-static void __ftrace_dump(bool disable_tracing);
+static void
+__ftrace_dump(bool disable_tracing, enum ftrace_dump_mode oops_dump_mode);
static unsigned int graph_hang_thresh;
/* Wrap the real function entry probe to avoid possible hanging */
@@ -267,7 +268,7 @@ static int trace_graph_entry_watchdog(struct ftrace_graph_ent *trace)
ftrace_graph_stop();
printk(KERN_WARNING "BUG: Function graph tracer hang!\n");
if (ftrace_dump_on_oops)
- __ftrace_dump(false);
+ __ftrace_dump(false, DUMP_ALL);
return 0;
}