Re: [patch 3/3] Trace sample
On Wed, 26 Sep 2007 11:22:43 -0700 David J. Wilder wrote: > Trace example - Adds the trace example to samples/ > > Signed-off-by: David Wilder <[EMAIL PROTECTED]> Acked-by: Randy Dunlap <[EMAIL PROTECTED]> > --- > samples/Kconfig|6 ++ > samples/Makefile |1 + > samples/trace/Makefile |4 + > samples/trace/fork_trace.c | 132 > > 4 files changed, 143 insertions(+), 0 deletions(-) > > diff --git a/samples/Kconfig b/samples/Kconfig > index 57bb223..e11c806 100644 > --- a/samples/Kconfig > +++ b/samples/Kconfig > @@ -13,4 +13,10 @@ config SAMPLE_MARKERS > help > This build markers example modules. > > +config SAMPLE_TRACE > + tristate "Build trace example -- loadable modules only" > + depends on TRACE && m > + help > + This builds a trace example module. > + > endif # SAMPLES > diff --git a/samples/Makefile b/samples/Makefile > index 5a4f0b6..8f6d05b 100644 > --- a/samples/Makefile > +++ b/samples/Makefile > @@ -1,3 +1,4 @@ > # Makefile for Linux samples code > > obj-$(CONFIG_SAMPLES)+= markers/ > +obj-$(CONFIG_SAMPLES)+= trace/ > diff --git a/samples/trace/Makefile b/samples/trace/Makefile > new file mode 100644 > index 000..a2da8af > --- /dev/null > +++ b/samples/trace/Makefile > @@ -0,0 +1,4 @@ > +# builds the trace example kernel modules; > +# then to use (as root): insmod > + > +obj-$(CONFIG_SAMPLE_TRACE) := fork_trace.o > diff --git a/samples/trace/fork_trace.c b/samples/trace/fork_trace.c > new file mode 100644 > index 000..71c04c7 > --- /dev/null > +++ b/samples/trace/fork_trace.c > @@ -0,0 +1,132 @@ > +/* > + * An example of using trace in a kprobes module > + * > + * Copyright (C) 2007 IBM Inc. > + * > + * David Wilder <[EMAIL PROTECTED]> > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License version 2 as > + * published by the Free Software Foundation. > + * > + * This program is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + * GNU General Public License for more details. > + * > + * You should have received a copy of the GNU General Public License > + * along with this program; if not, write to the Free Software > + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA > + * > + * --- > + * This module creates a trace channel and places a kprobe > + * on the function do_fork(). The value of current->pid is written to > + * the trace channel each time the kprobe is hit.. > + * > + * How to run the example: > + * $ mount -t debugfs /debug > + * $ insmod fork_trace.ko > + * > + * To view the data produced by the module: > + * $ cat /debug/trace_example/do_fork/trace0 > + * > + */ > + > +#include > +#include > +#include > +#include > + > +#define USE_GLOBAL_BUFFERS 1 > +#define USE_FLIGHT 1 > + > +#define PROBE_POINT "do_fork" > + > +static struct kprobe kp; > +static struct trace_info *kprobes_trace; > + > +#ifdef USE_GLOBAL_BUFFERS > +static DEFINE_SPINLOCK(trace_lock); > +#endif > + > +/* > + * Send formatted trace data to trace channel. > + * @note Preemption must be disabled to use this. > + */ > +static void trace_printf(struct trace_info *trace, const char *format, ...) > +{ > + va_list ap, aq; > + char *record; > + unsigned long flags; > + int len; > + > + if (!trace) > + return; > + > +#ifdef USE_GLOBAL_BUFFERS > + spin_lock_irqsave(&trace_lock, flags); > +#endif > + if (trace_running(trace)) { > + va_start(ap, format); > + va_copy(aq, ap); > + len = vsnprintf(NULL, 0, format, aq); > + va_end(aq); > + record = relay_reserve(trace->rchan, ++len); > + if (record) > + vsnprintf(record, len, format, ap); > + va_end(ap); > + } > +#ifdef USE_GLOBAL_BUFFERS > + spin_unlock_irqrestore(&trace_lock, flags); > +#endif > +} > + > +static int handler_pre(struct kprobe *p, struct pt_regs *regs) > +{ > + rcu_read_lock(); > + trace_printf(kprobes_trace, "%d\n", current->pid); > + rcu_read_unlock(); > + return 0; > +} > + > +int init_module(void) > +{ > + int ret; > + u32 flags = 0; > + > +#ifdef USE_GLOBAL_BUFFERS > + flags |= TRACE_GLOBAL_CHANNEL; > +#endif > + > +#ifdef USE_FLIGHT > + flags |= TRACE_FLIGHT_CHANNEL; > +#endif > + > + /* setup the trace */ > + kprobes_trace = trace_setup("trace_example", PROBE_POINT, > + 1024, 8, flags); > + if (IS_ERR(kprobes_trace)) > + return PTR_ERR(kprobes_trace); > + > + trace_start(kprobes_trace); > + > + /* setup the kprobe */ > + kp.pre_handler = handler_pre; > + kp.post_handler = NULL; > + kp.fault_han
Re: [patch 3/3] Trace sample
On Tue, 02 Oct 2007 09:33:25 -0700 David J. Wilder wrote: > Trace example - Adds the trace example to samples/ > > Signed-off-by: David Wilder <[EMAIL PROTECTED]> > --- > samples/Kconfig|6 ++ > samples/Makefile |1 + > samples/trace/Makefile |4 + > samples/trace/fork_trace.c | 132 > > 4 files changed, 143 insertions(+), 0 deletions(-) > > diff --git a/samples/Kconfig b/samples/Kconfig > index 57bb223..e11c806 100644 > --- a/samples/Kconfig > +++ b/samples/Kconfig > @@ -13,4 +13,10 @@ config SAMPLE_MARKERS > help > This build markers example modules. > > +config SAMPLE_TRACE > + tristate "Build trace example -- loadable modules only" > + depends on TRACE && m The sample code uses kprobes, so this should also be: depends on KPROBES Is (are?) kprobes always needed for trace? If so, the documentation probably should mention that also (along with relay & debugfs). > + help > + This builds a trace example module. > + > endif # SAMPLES > diff --git a/samples/Makefile b/samples/Makefile > index 5a4f0b6..8f6d05b 100644 > --- a/samples/Makefile > +++ b/samples/Makefile > @@ -1,3 +1,4 @@ > # Makefile for Linux samples code > > obj-$(CONFIG_SAMPLES)+= markers/ > +obj-$(CONFIG_SAMPLES)+= trace/ > diff --git a/samples/trace/Makefile b/samples/trace/Makefile > new file mode 100644 > index 000..a2da8af > --- /dev/null > +++ b/samples/trace/Makefile > @@ -0,0 +1,4 @@ > +# builds the trace example kernel modules; > +# then to use (as root): insmod > + > +obj-$(CONFIG_SAMPLE_TRACE) := fork_trace.o > diff --git a/samples/trace/fork_trace.c b/samples/trace/fork_trace.c > new file mode 100644 > index 000..71c04c7 > --- /dev/null > +++ b/samples/trace/fork_trace.c > @@ -0,0 +1,132 @@ > +/* > + * An example of using trace in a kprobes module > + * > + * Copyright (C) 2007 IBM Inc. > + * > + * David Wilder <[EMAIL PROTECTED]> > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License version 2 as > + * published by the Free Software Foundation. > + * > + * This program is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + * GNU General Public License for more details. > + * > + * You should have received a copy of the GNU General Public License > + * along with this program; if not, write to the Free Software > + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA > + * > + * --- > + * This module creates a trace channel and places a kprobe > + * on the function do_fork(). The value of current->pid is written to > + * the trace channel each time the kprobe is hit.. > + * > + * How to run the example: > + * $ mount -t debugfs /debug > + * $ insmod fork_trace.ko > + * > + * To view the data produced by the module: > + * $ cat /debug/trace_example/do_fork/trace0 > + * > + */ > + > +#include > +#include > +#include > +#include > + > +#define USE_GLOBAL_BUFFERS 1 > +#define USE_FLIGHT 1 > + > +#define PROBE_POINT "do_fork" > + > +static struct kprobe kp; > +static struct trace_info *kprobes_trace; > + > +#ifdef USE_GLOBAL_BUFFERS > +static DEFINE_SPINLOCK(trace_lock); > +#endif > + ... > + > +int init_module(void) > +{ > + int ret; > + u32 flags = 0; > + > +#ifdef USE_GLOBAL_BUFFERS > + flags |= TRACE_GLOBAL_CHANNEL; > +#endif > + > +#ifdef USE_FLIGHT > + flags |= TRACE_FLIGHT_CHANNEL; > +#endif > + > + /* setup the trace */ > + kprobes_trace = trace_setup("trace_example", PROBE_POINT, > + 1024, 8, flags); > + if (IS_ERR(kprobes_trace)) > + return PTR_ERR(kprobes_trace); > + > + trace_start(kprobes_trace); > + > + /* setup the kprobe */ > + kp.pre_handler = handler_pre; > + kp.post_handler = NULL; > + kp.fault_handler = NULL; > + kp.symbol_name = PROBE_POINT; > + ret = register_kprobe(&kp); > + if (ret) { > + printk(KERN_ERR "fork_trace: register_kprobe failed\n"); > + return ret; > + } > + return 0; > +} > + > +void cleanup_module(void) > +{ > + unregister_kprobe(&kp); > + trace_stop(kprobes_trace); > + trace_cleanup(kprobes_trace); > +} > +MODULE_LICENSE("GPL"); --- ~Randy - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [patch 3/3] Trace sample
Randy Dunlap wrote: On Tue, 02 Oct 2007 09:33:25 -0700 David J. Wilder wrote: Trace example - Adds the trace example to samples/ Signed-off-by: David Wilder <[EMAIL PROTECTED]> --- samples/Kconfig|6 ++ samples/Makefile |1 + samples/trace/Makefile |4 + samples/trace/fork_trace.c | 132 4 files changed, 143 insertions(+), 0 deletions(-) diff --git a/samples/Kconfig b/samples/Kconfig index 57bb223..e11c806 100644 --- a/samples/Kconfig +++ b/samples/Kconfig @@ -13,4 +13,10 @@ config SAMPLE_MARKERS help This build markers example modules. +config SAMPLE_TRACE + tristate "Build trace example -- loadable modules only" + depends on TRACE && m The sample code uses kprobes, so this should also be: depends on KPROBES Is (are?) kprobes always needed for trace? No, just the sample. If so, the documentation probably should mention that also (along with relay & debugfs). ... - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/