From 13d1cf7e702596e0cd8ec62afa6bd49c431f2d0c Mon Sep 17 00:00:00 2001 From: Seth Jennings Date: Tue, 16 Dec 2014 11:58:20 -0600 Subject: livepatch: samples: add sample live patching module Add a sample live patching module. Signed-off-by: Seth Jennings Reviewed-by: Miroslav Benes Reviewed-by: Petr Mladek Reviewed-by: Masami Hiramatsu Signed-off-by: Jiri Kosina --- samples/Kconfig | 7 +++ samples/Makefile | 2 +- samples/livepatch/Makefile | 1 + samples/livepatch/livepatch-sample.c | 87 ++++++++++++++++++++++++++++++++++++ 4 files changed, 96 insertions(+), 1 deletion(-) create mode 100644 samples/livepatch/Makefile create mode 100644 samples/livepatch/livepatch-sample.c (limited to 'samples') diff --git a/samples/Kconfig b/samples/Kconfig index 6181c2cc9ca0..0aed20df5f0b 100644 --- a/samples/Kconfig +++ b/samples/Kconfig @@ -63,4 +63,11 @@ config SAMPLE_RPMSG_CLIENT to communicate with an AMP-configured remote processor over the rpmsg bus. +config SAMPLE_LIVE_PATCHING + tristate "Build live patching sample -- loadable modules only" + depends on LIVE_PATCHING && m + help + Builds a sample live patch that replaces the procfs handler + for /proc/cmdline to print "this has been live patched". + endif # SAMPLES diff --git a/samples/Makefile b/samples/Makefile index 1a60c62e2045..f00257bcc5a7 100644 --- a/samples/Makefile +++ b/samples/Makefile @@ -1,4 +1,4 @@ # Makefile for Linux samples code -obj-$(CONFIG_SAMPLES) += kobject/ kprobes/ trace_events/ \ +obj-$(CONFIG_SAMPLES) += kobject/ kprobes/ trace_events/ livepatch/ \ hw_breakpoint/ kfifo/ kdb/ hidraw/ rpmsg/ seccomp/ diff --git a/samples/livepatch/Makefile b/samples/livepatch/Makefile new file mode 100644 index 000000000000..7f1cdc131a02 --- /dev/null +++ b/samples/livepatch/Makefile @@ -0,0 +1 @@ +obj-$(CONFIG_SAMPLE_LIVE_PATCHING) += livepatch-sample.o diff --git a/samples/livepatch/livepatch-sample.c b/samples/livepatch/livepatch-sample.c new file mode 100644 index 000000000000..21f159d51074 --- /dev/null +++ b/samples/livepatch/livepatch-sample.c @@ -0,0 +1,87 @@ +/* + * livepatch-sample.c - Kernel Live Patching Sample Module + * + * Copyright (C) 2014 Seth Jennings + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + * + * 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, see . + */ + +#include +#include +#include + +/* + * This (dumb) live patch overrides the function that prints the + * kernel boot cmdline when /proc/cmdline is read. + * + * Example: + * $ cat /proc/cmdline + * + * $ insmod livepatch-sample.ko + * $ cat /proc/cmdline + * this has been live patched + * $ echo 0 > /sys/kernel/livepatch/klp_sample/enabled + * + */ + +#include +static int livepatch_cmdline_proc_show(struct seq_file *m, void *v) +{ + seq_printf(m, "%s\n", "this has been live patched"); + return 0; +} + +static struct klp_func funcs[] = { + { + .old_name = "cmdline_proc_show", + .new_func = livepatch_cmdline_proc_show, + }, { } +}; + +static struct klp_object objs[] = { + { + /* name being NULL means vmlinux */ + .funcs = funcs, + }, { } +}; + +static struct klp_patch patch = { + .mod = THIS_MODULE, + .objs = objs, +}; + +static int livepatch_init(void) +{ + int ret; + + ret = klp_register_patch(&patch); + if (ret) + return ret; + ret = klp_enable_patch(&patch); + if (ret) { + WARN_ON(klp_unregister_patch(&patch)); + return ret; + } + return 0; +} + +static void livepatch_exit(void) +{ + WARN_ON(klp_disable_patch(&patch)); + WARN_ON(klp_unregister_patch(&patch)); +} + +module_init(livepatch_init); +module_exit(livepatch_exit); +MODULE_LICENSE("GPL"); -- cgit v1.2.3 From 700a3048aaa394b2a6d1468430f892151ce04a01 Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Tue, 23 Dec 2014 17:06:43 -0600 Subject: livepatch: samples: fix usage example comments Fix a few typos in the livepatch-sample.c usage example comments and add some whitespace to make the comments a little more legible. Reported-by: Udo Seidel Signed-off-by: Josh Poimboeuf Signed-off-by: Jiri Kosina --- samples/livepatch/livepatch-sample.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'samples') diff --git a/samples/livepatch/livepatch-sample.c b/samples/livepatch/livepatch-sample.c index 21f159d51074..fb8c8614e728 100644 --- a/samples/livepatch/livepatch-sample.c +++ b/samples/livepatch/livepatch-sample.c @@ -26,12 +26,16 @@ * kernel boot cmdline when /proc/cmdline is read. * * Example: + * * $ cat /proc/cmdline * + * * $ insmod livepatch-sample.ko * $ cat /proc/cmdline * this has been live patched - * $ echo 0 > /sys/kernel/livepatch/klp_sample/enabled + * + * $ echo 0 > /sys/kernel/livepatch/livepatch_sample/enabled + * $ cat /proc/cmdline * */ -- cgit v1.2.3 From 12cf89b550d13eb7cb86ef182bd6c04345a33a1f Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Tue, 3 Feb 2015 16:45:18 -0600 Subject: livepatch: rename config to CONFIG_LIVEPATCH Rename CONFIG_LIVE_PATCHING to CONFIG_LIVEPATCH to make the naming of the config and the code more consistent. Signed-off-by: Josh Poimboeuf Reviewed-by: Jingoo Han Signed-off-by: Jiri Kosina --- arch/x86/Kconfig | 2 +- arch/x86/include/asm/livepatch.h | 4 ++-- arch/x86/kernel/Makefile | 2 +- include/linux/livepatch.h | 4 ++-- kernel/livepatch/Kconfig | 6 +++--- kernel/livepatch/Makefile | 2 +- samples/Kconfig | 4 ++-- samples/livepatch/Makefile | 2 +- 8 files changed, 13 insertions(+), 13 deletions(-) (limited to 'samples') diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 29b095231276..11970b076862 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -17,7 +17,7 @@ config X86_64 depends on 64BIT select X86_DEV_DMA_OPS select ARCH_USE_CMPXCHG_LOCKREF - select HAVE_LIVE_PATCHING + select HAVE_LIVEPATCH ### Arch settings config X86 diff --git a/arch/x86/include/asm/livepatch.h b/arch/x86/include/asm/livepatch.h index 26e58134c8cb..a455a53d789a 100644 --- a/arch/x86/include/asm/livepatch.h +++ b/arch/x86/include/asm/livepatch.h @@ -24,7 +24,7 @@ #include #include -#ifdef CONFIG_LIVE_PATCHING +#ifdef CONFIG_LIVEPATCH static inline int klp_check_compiler_support(void) { #ifndef CC_USING_FENTRY @@ -40,7 +40,7 @@ static inline void klp_arch_set_pc(struct pt_regs *regs, unsigned long ip) regs->ip = ip; } #else -#error Live patching support is disabled; check CONFIG_LIVE_PATCHING +#error Live patching support is disabled; check CONFIG_LIVEPATCH #endif #endif /* _ASM_X86_LIVEPATCH_H */ diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile index 316b34e74c15..732223496968 100644 --- a/arch/x86/kernel/Makefile +++ b/arch/x86/kernel/Makefile @@ -63,7 +63,7 @@ obj-$(CONFIG_X86_MPPARSE) += mpparse.o obj-y += apic/ obj-$(CONFIG_X86_REBOOTFIXUPS) += reboot_fixups_32.o obj-$(CONFIG_DYNAMIC_FTRACE) += ftrace.o -obj-$(CONFIG_LIVE_PATCHING) += livepatch.o +obj-$(CONFIG_LIVEPATCH) += livepatch.o obj-$(CONFIG_FUNCTION_GRAPH_TRACER) += ftrace.o obj-$(CONFIG_FTRACE_SYSCALLS) += ftrace.o obj-$(CONFIG_X86_TSC) += trace_clock.o diff --git a/include/linux/livepatch.h b/include/linux/livepatch.h index f14c6fb262b4..95023fd8b00d 100644 --- a/include/linux/livepatch.h +++ b/include/linux/livepatch.h @@ -24,7 +24,7 @@ #include #include -#if IS_ENABLED(CONFIG_LIVE_PATCHING) +#if IS_ENABLED(CONFIG_LIVEPATCH) #include @@ -128,6 +128,6 @@ extern int klp_unregister_patch(struct klp_patch *); extern int klp_enable_patch(struct klp_patch *); extern int klp_disable_patch(struct klp_patch *); -#endif /* CONFIG_LIVE_PATCHING */ +#endif /* CONFIG_LIVEPATCH */ #endif /* _LINUX_LIVEPATCH_H_ */ diff --git a/kernel/livepatch/Kconfig b/kernel/livepatch/Kconfig index 347ee2221137..045022557936 100644 --- a/kernel/livepatch/Kconfig +++ b/kernel/livepatch/Kconfig @@ -1,15 +1,15 @@ -config HAVE_LIVE_PATCHING +config HAVE_LIVEPATCH bool help Arch supports kernel live patching -config LIVE_PATCHING +config LIVEPATCH bool "Kernel Live Patching" depends on DYNAMIC_FTRACE_WITH_REGS depends on MODULES depends on SYSFS depends on KALLSYMS_ALL - depends on HAVE_LIVE_PATCHING + depends on HAVE_LIVEPATCH help Say Y here if you want to support kernel live patching. This option has no runtime impact until a kernel "patch" diff --git a/kernel/livepatch/Makefile b/kernel/livepatch/Makefile index 7c1f00861428..e8780c0901d9 100644 --- a/kernel/livepatch/Makefile +++ b/kernel/livepatch/Makefile @@ -1,3 +1,3 @@ -obj-$(CONFIG_LIVE_PATCHING) += livepatch.o +obj-$(CONFIG_LIVEPATCH) += livepatch.o livepatch-objs := core.o diff --git a/samples/Kconfig b/samples/Kconfig index 0aed20df5f0b..224ebb46bed5 100644 --- a/samples/Kconfig +++ b/samples/Kconfig @@ -63,9 +63,9 @@ config SAMPLE_RPMSG_CLIENT to communicate with an AMP-configured remote processor over the rpmsg bus. -config SAMPLE_LIVE_PATCHING +config SAMPLE_LIVEPATCH tristate "Build live patching sample -- loadable modules only" - depends on LIVE_PATCHING && m + depends on LIVEPATCH && m help Builds a sample live patch that replaces the procfs handler for /proc/cmdline to print "this has been live patched". diff --git a/samples/livepatch/Makefile b/samples/livepatch/Makefile index 7f1cdc131a02..10319d7ea0b1 100644 --- a/samples/livepatch/Makefile +++ b/samples/livepatch/Makefile @@ -1 +1 @@ -obj-$(CONFIG_SAMPLE_LIVE_PATCHING) += livepatch-sample.o +obj-$(CONFIG_SAMPLE_LIVEPATCH) += livepatch-sample.o -- cgit v1.2.3 From 4e20e3a60b57efa1e5c26324ce0260d58be6c81b Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Mon, 9 Feb 2015 15:27:04 -0500 Subject: tracing: Update the TRACE_EVENT fields available in the sample code The sample code in samples/trace_events/ is extremely out of date and does not show all the new fields that have been added since the sample code was written. As most people are unaware of these new fields, adding sample code and explanations of those fields should help out. Signed-off-by: Steven Rostedt --- samples/trace_events/trace-events-sample.c | 19 +++- samples/trace_events/trace-events-sample.h | 145 ++++++++++++++++++++++++++--- 2 files changed, 150 insertions(+), 14 deletions(-) (limited to 'samples') diff --git a/samples/trace_events/trace-events-sample.c b/samples/trace_events/trace-events-sample.c index aabc4e970911..16c15c08ed38 100644 --- a/samples/trace_events/trace-events-sample.c +++ b/samples/trace_events/trace-events-sample.c @@ -10,12 +10,29 @@ #define CREATE_TRACE_POINTS #include "trace-events-sample.h" +static const char *random_strings[] = { + "Mother Goose", + "Snoopy", + "Gandalf", + "Frodo", + "One ring to rule them all" +}; static void simple_thread_func(int cnt) { + int array[6]; + int len = cnt % 5; + int i; + set_current_state(TASK_INTERRUPTIBLE); schedule_timeout(HZ); - trace_foo_bar("hello", cnt); + + for (i = 0; i < len; i++) + array[i] = i + 1; + array[i] = 0; + + trace_foo_bar("hello", cnt, array, random_strings[len], + tsk_cpus_allowed(current)); } static int simple_thread(void *arg) diff --git a/samples/trace_events/trace-events-sample.h b/samples/trace_events/trace-events-sample.h index 476429281389..dd65f7b8c0d9 100644 --- a/samples/trace_events/trace-events-sample.h +++ b/samples/trace_events/trace-events-sample.h @@ -1,6 +1,6 @@ /* * If TRACE_SYSTEM is defined, that will be the directory created - * in the ftrace directory under /sys/kernel/debug/tracing/events/ + * in the ftrace directory under /sys/kernel/tracing/events/ * * The define_trace.h below will also look for a file name of * TRACE_SYSTEM.h where TRACE_SYSTEM is what is defined here. @@ -54,44 +54,163 @@ * Here it is simply "foo, bar". * * struct: This defines the way the data will be stored in the ring buffer. - * There are currently two types of elements. __field and __array. - * a __field is broken up into (type, name). Where type can be any - * primitive type (integer, long or pointer). __field_struct() can - * be any static complex data value (struct, union, but not an array). - * For an array. there are three fields. (type, name, size). The - * type of elements in the array, the name of the field and the size - * of the array. + * The items declared here become part of a special structure + * called "__entry", which can be used in the fast_assign part of the + * TRACE_EVENT macro. + * + * Here are the currently defined types you can use: + * + * __field : Is broken up into type and name. Where type can be any + * primitive type (integer, long or pointer). + * + * __field(int, foo) + * + * __entry->foo = 5; + * + * __field_struct : This can be any static complex data type (struct, union + * but not an array). Be careful using complex types, as each + * event is limited in size, and copying large amounts of data + * into the ring buffer can slow things down. + * + * __field_struct(struct bar, foo) + * + * __entry->bar.x = y; + + * __array: There are three fields (type, name, size). The type is the + * type of elements in teh array, the name is the name of the array. + * size is the number of items in the array (not the total size). + * + * __array( char, foo, 10) is the same as saying: char foo[10]; + * + * Assigning arrays can be done like any array: + * + * __entry->foo[0] = 'a'; + * + * memcpy(__entry->foo, bar, 10); + * + * __dynamic_array: This is similar to array, but can vary is size from + * instance to instance of the tracepoint being called. + * Like __array, this too has three elements (type, name, size); + * type is the type of the element, name is the name of the array. + * The size is different than __array. It is not a static number, + * but the algorithm to figure out the length of the array for the + * specific instance of tracepoint. Again, size is the numebr of + * items in the array, not the total length in bytes. + * + * __dynamic_array( int, foo, bar) is similar to: int foo[bar]; + * + * Note, unlike arrays, you must use the __get_dynamic_array() macro + * to access the array. + * + * memcpy(__get_dynamic_array(foo), bar, 10); + * + * Notice, that "__entry" is not needed here. + * + * __string: This is a special kind of __dynamic_array. It expects to + * have a nul terminated character array passed to it (it allows + * for NULL too, which would be converted into "(null)"). __string + * takes two paramenter (name, src), where name is the name of + * the string saved, and src is the string to copy into the + * ring buffer. + * + * __string(foo, bar) is similar to: strcpy(foo, bar) + * + * To assign a string, use the helper macro __assign_str(). + * + * __assign_str(foo, bar); + * + * In most cases, the __assign_str() macro will take the same + * parameters as the __string() macro had to declare the string. + * + * __bitmask: This is another kind of __dynamic_array, but it expects + * an array of longs, and the number of bits to parse. It takes + * two parameters (name, nr_bits), where name is the name of the + * bitmask to save, and the nr_bits is the number of bits to record. + * + * __bitmask(target_cpu, nr_cpumask_bits) + * + * To assign a bitmask, use the __assign_bitmask() helper macro. + * + * __assign_bitmask(target_cpus, cpumask_bits(bar), nr_cpumask_bits); * - * __array( char, foo, 10) is the same as saying char foo[10]. * * fast_assign: This is a C like function that is used to store the items - * into the ring buffer. + * into the ring buffer. A special variable called "__entry" will be the + * structure that points into the ring buffer and has the same fields as + * described by the struct part of TRACE_EVENT above. * * printk: This is a way to print out the data in pretty print. This is * useful if the system crashes and you are logging via a serial line, * the data can be printed to the console using this "printk" method. + * This is also used to print out the data from the trace files. + * Again, the __entry macro is used to access the data from the ring buffer. + * + * Note, __dynamic_array, __string, and __bitmask require special helpers + * to access the data. + * + * For __dynamic_array(int, foo, bar) use __get_dynamic_array(foo) + * Use __get_dynamic_array_len(foo) to get the length of the array + * saved. + * + * For __string(foo, bar) use __get_str(foo) + * + * For __bitmask(target_cpus, nr_cpumask_bits) use __get_bitmask(target_cpus) + * * * Note, that for both the assign and the printk, __entry is the handler * to the data structure in the ring buffer, and is defined by the * TP_STRUCT__entry. */ + +/* + * It is OK to have helper functions in the file, but they need to be protected + * from being defined more than once. Remember, this file gets included more + * than once. + */ +#ifndef __TRACE_EVENT_SAMPLE_HELPER_FUNCTIONS +#define __TRACE_EVENT_SAMPLE_HELPER_FUNCTIONS +static inline int __length_of(const int *list) +{ + int i; + + if (!list) + return 0; + + for (i = 0; list[i]; i++) + ; + return i; +} +#endif + TRACE_EVENT(foo_bar, - TP_PROTO(char *foo, int bar), + TP_PROTO(const char *foo, int bar, const int *lst, + const char *string, const struct cpumask *mask), - TP_ARGS(foo, bar), + TP_ARGS(foo, bar, lst, string, mask), TP_STRUCT__entry( __array( char, foo, 10 ) __field( int, bar ) + __dynamic_array(int, list, __length_of(lst)) + __string( str, string ) + __bitmask( cpus, num_possible_cpus() ) ), TP_fast_assign( strlcpy(__entry->foo, foo, 10); __entry->bar = bar; + memcpy(__get_dynamic_array(list), lst, + __length_of(lst) * sizeof(int)); + __assign_str(str, string); + __assign_bitmask(cpus, cpumask_bits(mask), num_possible_cpus()); ), - TP_printk("foo %s %d", __entry->foo, __entry->bar) + TP_printk("foo %s %d %s %s (%s)", __entry->foo, __entry->bar, + __print_array(__get_dynamic_array(list), + __get_dynamic_array_len(list), + sizeof(int)), + __get_str(str), __get_bitmask(cpus)) ); #endif -- cgit v1.2.3 From c4c7eb29382c456b9be9858c357a490ae0ccd0f6 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Mon, 9 Feb 2015 16:05:55 -0500 Subject: tracing: Add TRACE_EVENT_CONDITION sample The sample code lacks an example of TRACE_EVENT_CONDITION, and it has been expressed to me that this feature for TRACE_EVENT is not well known and not used when it could be. Signed-off-by: Steven Rostedt --- samples/trace_events/trace-events-sample.c | 3 ++ samples/trace_events/trace-events-sample.h | 58 ++++++++++++++++++++++++++++++ 2 files changed, 61 insertions(+) (limited to 'samples') diff --git a/samples/trace_events/trace-events-sample.c b/samples/trace_events/trace-events-sample.c index 16c15c08ed38..c396a49b5d78 100644 --- a/samples/trace_events/trace-events-sample.c +++ b/samples/trace_events/trace-events-sample.c @@ -31,8 +31,11 @@ static void simple_thread_func(int cnt) array[i] = i + 1; array[i] = 0; + /* Silly tracepoints */ trace_foo_bar("hello", cnt, array, random_strings[len], tsk_cpus_allowed(current)); + + trace_foo_bar_with_cond("Some times print", cnt); } static int simple_thread(void *arg) diff --git a/samples/trace_events/trace-events-sample.h b/samples/trace_events/trace-events-sample.h index dd65f7b8c0d9..c3232340914d 100644 --- a/samples/trace_events/trace-events-sample.h +++ b/samples/trace_events/trace-events-sample.h @@ -212,6 +212,64 @@ TRACE_EVENT(foo_bar, sizeof(int)), __get_str(str), __get_bitmask(cpus)) ); + +/* + * There may be a case where a tracepoint should only be called if + * some condition is set. Otherwise the tracepoint should not be called. + * But to do something like: + * + * if (cond) + * trace_foo(); + * + * Would cause a little overhead when tracing is not enabled, and that + * overhead, even if small, is not something we want. As tracepoints + * use static branch (aka jump_labels), where no branch is taken to + * skip the tracepoint when not enabled, and a jmp is placed to jump + * to the tracepoint code when it is enabled, having a if statement + * nullifies that optimization. It would be nice to place that + * condition within the static branch. This is where TRACE_EVENT_CONDITION + * comes in. + * + * TRACE_EVENT_CONDITION() is just like TRACE_EVENT, except it adds another + * parameter just after args. Where TRACE_EVENT has: + * + * TRACE_EVENT(name, proto, args, struct, assign, printk) + * + * the CONDITION version has: + * + * TRACE_EVENT_CONDITION(name, proto, args, cond, struct, assign, printk) + * + * Everything is the same as TRACE_EVENT except for the new cond. Think + * of the cond variable as: + * + * if (cond) + * trace_foo_bar_with_cond(); + * + * Except that the logic for the if branch is placed after the static branch. + * That is, the if statement that processes the condition will not be + * executed unless that traecpoint is enabled. Otherwise it still remains + * a nop. + */ +TRACE_EVENT_CONDITION(foo_bar_with_cond, + + TP_PROTO(const char *foo, int bar), + + TP_ARGS(foo, bar), + + TP_CONDITION(!(bar % 10)), + + TP_STRUCT__entry( + __string( foo, foo ) + __field( int, bar ) + ), + + TP_fast_assign( + __assign_str(foo, foo); + __entry->bar = bar; + ), + + TP_printk("foo %s %d", __get_str(foo), __entry->bar) +); #endif /***** NOTICE! The #if protection ends here. *****/ -- cgit v1.2.3 From 6adc13f8c096736957444ffa2aa11421b5671aef Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Mon, 9 Feb 2015 16:32:19 -0500 Subject: tracing: Add TRACE_EVENT_FN example If a function should be called before a tracepoint is enabled and/or after it is disabled, the TRACE_EVENT_FN() serves this purpose. But it is not well documented. Having it as a sample would help developers to know how to use it. Signed-off-by: Steven Rostedt --- samples/trace_events/trace-events-sample.c | 51 ++++++++++++++++++++++++++++++ samples/trace_events/trace-events-sample.h | 44 ++++++++++++++++++++++++++ 2 files changed, 95 insertions(+) (limited to 'samples') diff --git a/samples/trace_events/trace-events-sample.c b/samples/trace_events/trace-events-sample.c index c396a49b5d78..39d4484aef53 100644 --- a/samples/trace_events/trace-events-sample.c +++ b/samples/trace_events/trace-events-sample.c @@ -49,6 +49,52 @@ static int simple_thread(void *arg) } static struct task_struct *simple_tsk; +static struct task_struct *simple_tsk_fn; + +static void simple_thread_func_fn(int cnt) +{ + set_current_state(TASK_INTERRUPTIBLE); + schedule_timeout(HZ); + + /* More silly tracepoints */ + trace_foo_bar_with_fn("Look at me", cnt); +} + +static int simple_thread_fn(void *arg) +{ + int cnt = 0; + + while (!kthread_should_stop()) + simple_thread_func_fn(cnt++); + + return 0; +} + +static DEFINE_MUTEX(thread_mutex); + +void foo_bar_reg(void) +{ + pr_info("Starting thread for foo_bar_fn\n"); + /* + * We shouldn't be able to start a trace when the module is + * unloading (there's other locks to prevent that). But + * for consistency sake, we still take the thread_mutex. + */ + mutex_lock(&thread_mutex); + simple_tsk_fn = kthread_run(simple_thread_fn, NULL, "event-sample-fn"); + mutex_unlock(&thread_mutex); +} + +void foo_bar_unreg(void) +{ + pr_info("Killing thread for foo_bar_fn\n"); + /* protect against module unloading */ + mutex_lock(&thread_mutex); + if (simple_tsk_fn) + kthread_stop(simple_tsk_fn); + simple_tsk_fn = NULL; + mutex_unlock(&thread_mutex); +} static int __init trace_event_init(void) { @@ -62,6 +108,11 @@ static int __init trace_event_init(void) static void __exit trace_event_exit(void) { kthread_stop(simple_tsk); + mutex_lock(&thread_mutex); + if (simple_tsk_fn) + kthread_stop(simple_tsk_fn); + simple_tsk_fn = NULL; + mutex_unlock(&thread_mutex); } module_init(trace_event_init); diff --git a/samples/trace_events/trace-events-sample.h b/samples/trace_events/trace-events-sample.h index c3232340914d..d0be8411b527 100644 --- a/samples/trace_events/trace-events-sample.h +++ b/samples/trace_events/trace-events-sample.h @@ -270,6 +270,50 @@ TRACE_EVENT_CONDITION(foo_bar_with_cond, TP_printk("foo %s %d", __get_str(foo), __entry->bar) ); + +void foo_bar_reg(void); +void foo_bar_unreg(void); + +/* + * Now in the case that some function needs to be called when the + * tracepoint is enabled and/or when it is disabled, the + * TRACE_EVENT_FN() serves this purpose. This is just like TRACE_EVENT() + * but adds two more parameters at the end: + * + * TRACE_EVENT_FN( name, proto, args, struct, assign, printk, reg, unreg) + * + * reg and unreg are functions with the prototype of: + * + * void reg(void) + * + * The reg function gets called before the tracepoint is enabled, and + * the unreg function gets called after the tracepoint is disabled. + * + * Note, reg and unreg are allowed to be NULL. If you only need to + * call a function before enabling, or after disabling, just set one + * function and pass in NULL for the other parameter. + */ +TRACE_EVENT_FN(foo_bar_with_fn, + + TP_PROTO(const char *foo, int bar), + + TP_ARGS(foo, bar), + + TP_STRUCT__entry( + __string( foo, foo ) + __field( int, bar ) + ), + + TP_fast_assign( + __assign_str(foo, foo); + __entry->bar = bar; + ), + + TP_printk("foo %s %d", __get_str(foo), __entry->bar), + + foo_bar_reg, foo_bar_unreg +); + #endif /***** NOTICE! The #if protection ends here. *****/ -- cgit v1.2.3 From 7496946a88ab48830f3101c08f8e770cc0902bbb Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Mon, 9 Feb 2015 17:14:04 -0500 Subject: tracing: Add samples of DECLARE_EVENT_CLASS() and DEFINE_EVENT() Add to samples/trace_events/ the macros DECLARE_EVENT_CLASS() and DEFINE_EVENT() and recommend using them over multiple TRACE_EVENT() macros if the multiple events have the same format. Signed-off-by: Steven Rostedt --- samples/trace_events/trace-events-sample.c | 7 +++ samples/trace_events/trace-events-sample.h | 81 ++++++++++++++++++++++++++++++ 2 files changed, 88 insertions(+) (limited to 'samples') diff --git a/samples/trace_events/trace-events-sample.c b/samples/trace_events/trace-events-sample.c index 39d4484aef53..880a7d1d27d2 100644 --- a/samples/trace_events/trace-events-sample.c +++ b/samples/trace_events/trace-events-sample.c @@ -35,7 +35,13 @@ static void simple_thread_func(int cnt) trace_foo_bar("hello", cnt, array, random_strings[len], tsk_cpus_allowed(current)); + trace_foo_with_template_simple("HELLO", cnt); + trace_foo_bar_with_cond("Some times print", cnt); + + trace_foo_with_template_cond("prints other times", cnt); + + trace_foo_with_template_print("I have to be different", cnt); } static int simple_thread(void *arg) @@ -58,6 +64,7 @@ static void simple_thread_func_fn(int cnt) /* More silly tracepoints */ trace_foo_bar_with_fn("Look at me", cnt); + trace_foo_with_template_fn("Look at me too", cnt); } static int simple_thread_fn(void *arg) diff --git a/samples/trace_events/trace-events-sample.h b/samples/trace_events/trace-events-sample.h index d0be8411b527..a2c8b02b6359 100644 --- a/samples/trace_events/trace-events-sample.h +++ b/samples/trace_events/trace-events-sample.h @@ -314,6 +314,87 @@ TRACE_EVENT_FN(foo_bar_with_fn, foo_bar_reg, foo_bar_unreg ); +/* + * Each TRACE_EVENT macro creates several helper functions to produce + * the code to add the tracepoint, create the files in the trace + * directory, hook it to perf, assign the values and to print out + * the raw data from the ring buffer. To prevent too much bloat, + * if there are more than one tracepoint that uses the same format + * for the proto, args, struct, assign and printk, and only the name + * is different, it is highly recommended to use the DECLARE_EVENT_CLASS + * + * DECLARE_EVENT_CLASS() macro creates most of the functions for the + * tracepoint. Then DEFINE_EVENT() is use to hook a tracepoint to those + * functions. This DEFINE_EVENT() is an instance of the class and can + * be enabled and disabled separately from other events (either TRACE_EVENT + * or other DEFINE_EVENT()s). + * + * Note, TRACE_EVENT() itself is simply defined as: + * + * #define TRACE_EVENT(name, proto, args, tstruct, assign, printk) \ + * DEFINE_EVENT_CLASS(name, proto, args, tstruct, assign, printk); \ + * DEFINE_EVENT(name, name, proto, args) + * + * The DEFINE_EVENT() also can be declared with conditions and reg functions: + * + * DEFINE_EVENT_CONDITION(template, name, proto, args, cond); + * DEFINE_EVENT_FN(template, name, proto, args, reg, unreg); + */ +DECLARE_EVENT_CLASS(foo_template, + + TP_PROTO(const char *foo, int bar), + + TP_ARGS(foo, bar), + + TP_STRUCT__entry( + __string( foo, foo ) + __field( int, bar ) + ), + + TP_fast_assign( + __assign_str(foo, foo); + __entry->bar = bar; + ), + + TP_printk("foo %s %d", __get_str(foo), __entry->bar) +); + +/* + * Here's a better way for the previous samples (except, the first + * exmaple had more fields and could not be used here). + */ +DEFINE_EVENT(foo_template, foo_with_template_simple, + TP_PROTO(const char *foo, int bar), + TP_ARGS(foo, bar)); + +DEFINE_EVENT_CONDITION(foo_template, foo_with_template_cond, + TP_PROTO(const char *foo, int bar), + TP_ARGS(foo, bar), + TP_CONDITION(!(bar % 8))); + + +DEFINE_EVENT_FN(foo_template, foo_with_template_fn, + TP_PROTO(const char *foo, int bar), + TP_ARGS(foo, bar), + foo_bar_reg, foo_bar_unreg); + +/* + * Anytime two events share basically the same values and have + * the same output, use the DECLARE_EVENT_CLASS() and DEFINE_EVENT() + * when ever possible. + */ + +/* + * If the event is similar to the DECLARE_EVENT_CLASS, but you need + * to have a different output, then use DEFINE_EVENT_PRINT() which + * lets you override the TP_printk() of the class. + */ + +DEFINE_EVENT_PRINT(foo_template, foo_with_template_print, + TP_PROTO(const char *foo, int bar), + TP_ARGS(foo, bar), + TP_printk("bar %s %d", __get_str(foo), __entry->bar)); + #endif /***** NOTICE! The #if protection ends here. *****/ -- cgit v1.2.3 From 3a9af0bd34410a255d27024ea1bc28dc4e3a0044 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Tue, 17 Feb 2015 13:47:58 -0800 Subject: samples/seccomp: improve label helper Fixes a potential corruption with uninitialized stack memory in the seccomp BPF sample program. [akpm@linux-foundation.org: coding-style fixlet] Signed-off-by: Kees Cook Reported-by: Robert Swiecki Tested-by: Robert Swiecki Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- samples/seccomp/bpf-fancy.c | 4 +++- samples/seccomp/bpf-helper.c | 6 ++++++ 2 files changed, 9 insertions(+), 1 deletion(-) (limited to 'samples') diff --git a/samples/seccomp/bpf-fancy.c b/samples/seccomp/bpf-fancy.c index 8eb483aaec46..e8b24f443709 100644 --- a/samples/seccomp/bpf-fancy.c +++ b/samples/seccomp/bpf-fancy.c @@ -25,7 +25,9 @@ int main(int argc, char **argv) { - struct bpf_labels l; + struct bpf_labels l = { + .count = 0, + }; static const char msg1[] = "Please type something: "; static const char msg2[] = "You typed: "; char buf[256]; diff --git a/samples/seccomp/bpf-helper.c b/samples/seccomp/bpf-helper.c index 579cfe331886..05cb4d5ff9f5 100644 --- a/samples/seccomp/bpf-helper.c +++ b/samples/seccomp/bpf-helper.c @@ -10,6 +10,7 @@ */ #include +#include #include #include "bpf-helper.h" @@ -63,6 +64,11 @@ __u32 seccomp_bpf_label(struct bpf_labels *labels, const char *label) { struct __bpf_label *begin = labels->labels, *end; int id; + + if (labels->count == BPF_LABELS_MAX) { + fprintf(stderr, "Too many labels\n"); + exit(1); + } if (labels->count == 0) { begin->label = label; begin->location = 0xffffffff; -- cgit v1.2.3 From 04303f8ec14269b0ea2553863553bc7eaadca1f8 Mon Sep 17 00:00:00 2001 From: Pavel Machek Date: Sat, 14 Mar 2015 21:57:22 +0100 Subject: HID: samples/hidraw: make it possible to select device Makefile that can actually build the example, and allow selecting device to work on. Signed-off-by: Pavel Machek Signed-off-by: Jiri Kosina --- samples/hidraw/Makefile | 2 ++ samples/hidraw/hid-example.c | 6 +++++- 2 files changed, 7 insertions(+), 1 deletion(-) (limited to 'samples') diff --git a/samples/hidraw/Makefile b/samples/hidraw/Makefile index 382eeae77bd6..a9ab96188fbe 100644 --- a/samples/hidraw/Makefile +++ b/samples/hidraw/Makefile @@ -8,3 +8,5 @@ hostprogs-y := hid-example always := $(hostprogs-y) HOSTCFLAGS_hid-example.o += -I$(objtree)/usr/include + +all: hid-example diff --git a/samples/hidraw/hid-example.c b/samples/hidraw/hid-example.c index 512a7e50bcae..92e6c1511910 100644 --- a/samples/hidraw/hid-example.c +++ b/samples/hidraw/hid-example.c @@ -46,10 +46,14 @@ int main(int argc, char **argv) char buf[256]; struct hidraw_report_descriptor rpt_desc; struct hidraw_devinfo info; + char *device = "/dev/hidraw0"; + + if (argc > 1) + device = argv[1]; /* Open the Device with non-blocking reads. In real life, don't use a hard coded path; use libudev instead. */ - fd = open("/dev/hidraw0", O_RDWR|O_NONBLOCK); + fd = open(device, O_RDWR|O_NONBLOCK); if (fd < 0) { perror("Unable to open device"); -- cgit v1.2.3