diff options
| -rw-r--r-- | Documentation/kernel-parameters.txt | 6 | ||||
| -rw-r--r-- | Documentation/trace/ftrace.txt | 6 | ||||
| -rw-r--r-- | drivers/char/sysrq.c | 2 | ||||
| -rw-r--r-- | include/linux/ftrace.h | 4 | ||||
| -rw-r--r-- | include/linux/kernel.h | 11 | ||||
| -rw-r--r-- | kernel/trace/trace.c | 51 | ||||
| -rw-r--r-- | kernel/trace/trace_selftest.c | 5 |
7 files changed, 64 insertions, 21 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index e4cbca58536c..ab67b33300fb 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 03485bfbd797..52011815c905 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 59de2525d303..d4e8b213a462 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 01e6adea07ec..ea5b1aae0e8b 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 9365227dbaf6..9fb1c1299032 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 bed83cab6da2..7b516c7ef9a0 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 9398034f814a..6a9d36ddfcf2 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; } |