On Thu, 2010-01-14 at 08:59 -0600, Jason Wessel wrote: > Add in a helper function to allow the kdb shell to dump the ftrace > buffer. >
Acked-by: Steven Rostedt <[email protected]> If this is the final version, I could queue it up in my tree for 34, and push it off to Ingo. -- Steve > Signed-off-by: Jason Wessel <[email protected]> > --- > Documentation/DocBook/kgdb.tmpl | 3 +- > kernel/trace/Makefile | 3 + > kernel/trace/trace.c | 48 +++++++--------- > kernel/trace/trace.h | 17 ++++++ > kernel/trace/trace_kdb.c | 116 > +++++++++++++++++++++++++++++++++++++++ > 5 files changed, 160 insertions(+), 27 deletions(-) > create mode 100644 kernel/trace/trace_kdb.c > > diff --git a/Documentation/DocBook/kgdb.tmpl b/Documentation/DocBook/kgdb.tmpl > index bbf4a22..b01b5b1 100644 > --- a/Documentation/DocBook/kgdb.tmpl > +++ b/Documentation/DocBook/kgdb.tmpl > @@ -675,7 +675,8 @@ Task Addr Pid Parent [*] cpu State Thread > Command > <itemizedlist> > <listitem><para>A simple shell</para></listitem> > <listitem><para>The kdb core command set</para></listitem> > - <listitem><para>A registration API to register additional kdb shell > commands.</para></listitem> > + <listitem><para>A registration API to register additional kdb shell > commands.</para> > + <para>A good example of a self contained kdb module is the "ftdump" > command for dumping the ftrace buffer. See: > kernel/trace/trace_kdb.c</para></listitem> > <listitem><para>The implementation for kdb_printf() which emit > messages directly to I/O drivers, bypassing the kernel log.</para></listitem> > <listitem><para>SW / HW breakpoint management for the kdb > shell</para></listitem> > </itemizedlist> > diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile > index cd9ecd8..c48a28f 100644 > --- a/kernel/trace/Makefile > +++ b/kernel/trace/Makefile > @@ -56,5 +56,8 @@ obj-$(CONFIG_EVENT_TRACING) += trace_events_filter.o > obj-$(CONFIG_KPROBE_EVENT) += trace_kprobe.o > obj-$(CONFIG_KSYM_TRACER) += trace_ksym.o > obj-$(CONFIG_EVENT_TRACING) += power-traces.o > +ifeq ($(CONFIG_TRACING),y) > +obj-$(CONFIG_KGDB_KDB) += trace_kdb.o > +endif > > libftrace-y := ftrace.o > diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c > index 0df1b0f..b3c786a 100644 > --- a/kernel/trace/trace.c > +++ b/kernel/trace/trace.c > @@ -100,14 +100,11 @@ static inline void ftrace_enable_cpu(void) > preempt_enable(); > } > > -static cpumask_var_t __read_mostly tracing_buffer_mask; > +cpumask_var_t __read_mostly tracing_buffer_mask; > > /* Define which cpu buffers are currently read in trace_pipe */ > static cpumask_var_t tracing_reader_cpumask; > > -#define for_each_tracing_cpu(cpu) \ > - for_each_cpu(cpu, tracing_buffer_mask) > - > /* > * ftrace_dump_on_oops - variable to dump ftrace buffer on oops > * > @@ -1409,11 +1406,6 @@ int trace_vprintk(unsigned long ip, const char *fmt, > va_list args) > } > EXPORT_SYMBOL_GPL(trace_vprintk); > > -enum trace_file_type { > - TRACE_FILE_LAT_FMT = 1, > - TRACE_FILE_ANNOTATE = 2, > -}; > - > static void trace_iterator_increment(struct trace_iterator *iter) > { > /* Don't allow ftrace to trace into the ring buffers */ > @@ -1503,7 +1495,7 @@ struct trace_entry *trace_find_next_entry(struct > trace_iterator *iter, > } > > /* Find the next real entry, and increment the iterator to the next entry */ > -static void *find_next_entry_inc(struct trace_iterator *iter) > +void *trace_find_next_entry_inc(struct trace_iterator *iter) > { > iter->ent = __find_next_entry(iter, &iter->cpu, &iter->ts); > > @@ -1536,12 +1528,12 @@ static void *s_next(struct seq_file *m, void *v, > loff_t *pos) > return NULL; > > if (iter->idx < 0) > - ent = find_next_entry_inc(iter); > + ent = trace_find_next_entry_inc(iter); > else > ent = iter; > > while (ent && iter->idx < i) > - ent = find_next_entry_inc(iter); > + ent = trace_find_next_entry_inc(iter); > > iter->pos = *pos; > > @@ -1878,7 +1870,7 @@ static enum print_line_t print_bin_fmt(struct > trace_iterator *iter) > return event ? event->binary(iter, 0) : TRACE_TYPE_HANDLED; > } > > -static int trace_empty(struct trace_iterator *iter) > +int trace_empty(struct trace_iterator *iter) > { > int cpu; > > @@ -1909,7 +1901,7 @@ static int trace_empty(struct trace_iterator *iter) > } > > /* Called with trace_event_read_lock() held. */ > -static enum print_line_t print_trace_line(struct trace_iterator *iter) > +enum print_line_t print_trace_line(struct trace_iterator *iter) > { > enum print_line_t ret; > > @@ -3074,7 +3066,7 @@ waitagain: > iter->pos = -1; > > trace_event_read_lock(); > - while (find_next_entry_inc(iter) != NULL) { > + while (trace_find_next_entry_inc(iter) != NULL) { > enum print_line_t ret; > int len = iter->seq.len; > > @@ -3156,7 +3148,7 @@ tracing_fill_pipe_page(size_t rem, struct > trace_iterator *iter) > if (ret != TRACE_TYPE_NO_CONSUME) > trace_consume(iter); > rem -= count; > - if (!find_next_entry_inc(iter)) { > + if (!trace_find_next_entry_inc(iter)) { > rem = 0; > iter->ent = NULL; > break; > @@ -3209,7 +3201,7 @@ static ssize_t tracing_splice_read_pipe(struct file > *filp, > if (ret <= 0) > goto out_err; > > - if (!iter->ent && !find_next_entry_inc(iter)) { > + if (!iter->ent && !trace_find_next_entry_inc(iter)) { > ret = -EFAULT; > goto out_err; > } > @@ -4262,7 +4254,7 @@ static struct notifier_block trace_die_notifier = { > */ > #define KERN_TRACE KERN_EMERG > > -static void > +void > trace_printk_seq(struct trace_seq *s) > { > /* Probably should print a warning here. */ > @@ -4277,6 +4269,13 @@ trace_printk_seq(struct trace_seq *s) > trace_seq_init(s); > } > > +void trace_init_global_iter(struct trace_iterator *iter) > +{ > + iter->tr = &global_trace; > + iter->trace = current_trace; > + iter->cpu_file = TRACE_PIPE_ALL_CPU; > +} > + > static void __ftrace_dump(bool disable_tracing) > { > static arch_spinlock_t ftrace_dump_lock = > @@ -4301,8 +4300,10 @@ static void __ftrace_dump(bool disable_tracing) > if (disable_tracing) > ftrace_kill(); > > + trace_init_global_iter(&iter); > + > for_each_tracing_cpu(cpu) { > - atomic_inc(&global_trace.data[cpu]->disabled); > + atomic_inc(&iter.tr->data[cpu]->disabled); > } > > old_userobj = trace_flags & TRACE_ITER_SYM_USEROBJ; > @@ -4312,11 +4313,6 @@ static void __ftrace_dump(bool disable_tracing) > > 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; > - > /* > * We need to stop all tracing on all CPUS to read the > * the next buffer. This is a bit expensive, but is > @@ -4338,7 +4334,7 @@ static void __ftrace_dump(bool disable_tracing) > iter.iter_flags |= TRACE_FILE_LAT_FMT; > iter.pos = -1; > > - if (find_next_entry_inc(&iter) != NULL) { > + if (trace_find_next_entry_inc(&iter) != NULL) { > int ret; > > ret = print_trace_line(&iter); > @@ -4359,7 +4355,7 @@ static void __ftrace_dump(bool disable_tracing) > trace_flags |= old_userobj; > > for_each_tracing_cpu(cpu) { > - atomic_dec(&global_trace.data[cpu]->disabled); > + atomic_dec(&iter.tr->data[cpu]->disabled); > } > tracing_on(); > } > diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h > index 4df6a77..563e6f8 100644 > --- a/kernel/trace/trace.h > +++ b/kernel/trace/trace.h > @@ -352,6 +352,12 @@ struct trace_entry *tracing_get_trace_entry(struct > trace_array *tr, > struct trace_entry *trace_find_next_entry(struct trace_iterator *iter, > int *ent_cpu, u64 *ent_ts); > > +int trace_empty(struct trace_iterator *iter); > + > +void *trace_find_next_entry_inc(struct trace_iterator *iter); > + > +void trace_init_global_iter(struct trace_iterator *iter); > + > void default_wait_pipe(struct trace_iterator *iter); > void poll_wait_pipe(struct trace_iterator *iter); > > @@ -391,6 +397,15 @@ void tracing_start_sched_switch_record(void); > int register_tracer(struct tracer *type); > void unregister_tracer(struct tracer *type); > int is_tracing_stopped(void); > +enum trace_file_type { > + TRACE_FILE_LAT_FMT = 1, > + TRACE_FILE_ANNOTATE = 2, > +}; > + > +extern cpumask_var_t __read_mostly tracing_buffer_mask; > + > +#define for_each_tracing_cpu(cpu) \ > + for_each_cpu(cpu, tracing_buffer_mask) > > extern int process_new_ksym_entry(char *ksymname, int op, unsigned long > addr); > > @@ -483,6 +498,8 @@ trace_array_vprintk(struct trace_array *tr, > unsigned long ip, const char *fmt, va_list args); > int trace_array_printk(struct trace_array *tr, > unsigned long ip, const char *fmt, ...); > +void trace_printk_seq(struct trace_seq *s); > +enum print_line_t print_trace_line(struct trace_iterator *iter); > > extern unsigned long trace_flags; > > diff --git a/kernel/trace/trace_kdb.c b/kernel/trace/trace_kdb.c > new file mode 100644 > index 0000000..9227ff3 > --- /dev/null > +++ b/kernel/trace/trace_kdb.c > @@ -0,0 +1,116 @@ > +/* > + * kdb helper for dumping the ftrace buffer > + * > + * Copyright (C) 2010 Jason Wessel <[email protected]> > + * > + * ftrace_dump_buf based on ftrace_dump: > + * Copyright (C) 2007-2008 Steven Rostedt <[email protected]> > + * Copyright (C) 2008 Ingo Molnar <[email protected]> > + * > + */ > +#include <linux/init.h> > +#include <linux/kgdb.h> > +#include <linux/kdb.h> > +#include <linux/ftrace.h> > + > +#include "../debug/kdb/kdb_private.h" > +#include "trace.h" > +#include "trace_output.h" > + > +static void ftrace_dump_buf(int skip_lines) > +{ > + /* use static because iter can be a bit big for the stack */ > + static struct trace_iterator iter; > + unsigned int old_userobj; > + int cnt = 0, cpu; > + > + trace_init_global_iter(&iter); > + > + for_each_tracing_cpu(cpu) { > + atomic_inc(&iter.tr->data[cpu]->disabled); > + } > + > + old_userobj = trace_flags; > + > + /* don't look at user memory in panic mode */ > + trace_flags &= ~TRACE_ITER_SYM_USEROBJ; > + > + kdb_printf("Dumping ftrace buffer:\n"); > + > + /* reset all but tr, trace, and overruns */ > + memset(&iter.seq, 0, > + sizeof(struct trace_iterator) - > + offsetof(struct trace_iterator, seq)); > + iter.iter_flags |= TRACE_FILE_LAT_FMT; > + iter.pos = -1; > + > + for_each_tracing_cpu(cpu) > + iter.buffer_iter[cpu] = > + ring_buffer_read_start(iter.tr->buffer, cpu); > + > + if (!trace_empty(&iter)) > + trace_find_next_entry_inc(&iter); > + while (!trace_empty(&iter)) { > + if (!cnt) > + kdb_printf("---------------------------------\n"); > + cnt++; > + > + if (trace_find_next_entry_inc(&iter) != NULL && !skip_lines) > + print_trace_line(&iter); > + if (!skip_lines) > + trace_printk_seq(&iter.seq); > + else > + skip_lines--; > + if (KDB_FLAG(CMD_INTERRUPT)) > + goto out; > + } > + > + if (!cnt) > + kdb_printf(" (ftrace buffer empty)\n"); > + else > + kdb_printf("---------------------------------\n"); > + > +out: > + trace_flags = old_userobj; > + > + for_each_tracing_cpu(cpu) { > + atomic_dec(&iter.tr->data[cpu]->disabled); > + } > + > + for_each_tracing_cpu(cpu) > + if (iter.buffer_iter[cpu]) > + ring_buffer_read_finish(iter.buffer_iter[cpu]); > +} > + > +/* > + * kdb_ftdump - Dump the ftrace log buffer > + */ > +static int kdb_ftdump(int argc, const char **argv) > +{ > + int skip_lines = 0; > + char *cp; > + > + if (argc > 1) > + return KDB_ARGCOUNT; > + > + if (argc) { > + skip_lines = simple_strtol(argv[1], &cp, 0); > + if (*cp) > + skip_lines = 0; > + } > + > + kdb_trap_printk++; > + ftrace_dump_buf(skip_lines); > + kdb_trap_printk--; > + > + return 0; > +} > + > +static __init int kdb_ftrace_register(void) > +{ > + kdb_register_repeat("ftdump", kdb_ftdump, "", "Dump ftrace log", > + 0, KDB_REPEAT_NONE); > + return 0; > +} > + > +late_initcall(kdb_ftrace_register); ------------------------------------------------------------------------------ Throughout its 18-year history, RSA Conference consistently attracts the world's best and brightest in the field, creating opportunities for Conference attendees to learn about information security's most important issues through interactions with peers, luminaries and emerging and established companies. http://p.sf.net/sfu/rsaconf-dev2dev _______________________________________________ Kgdb-bugreport mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/kgdb-bugreport
