diff options
Diffstat (limited to 'kernel/trace')
33 files changed, 3277 insertions, 682 deletions
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index 25a0fcfa7a5d..91e885194dbc 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -141,6 +141,15 @@ menuconfig FTRACE if FTRACE +config BOOTTIME_TRACING + bool "Boot-time Tracing support" + depends on BOOT_CONFIG && TRACING + default y + help + Enable developer to setup ftrace subsystem via supplemental + kernel cmdline at boot time for debugging (tracing) driver + initialization and boot process. + config FUNCTION_TRACER bool "Kernel Function Tracer" depends on HAVE_FUNCTION_TRACER @@ -172,6 +181,77 @@ config FUNCTION_GRAPH_TRACER the return value. This is done by setting the current return address on the current task structure into a stack of calls. +config DYNAMIC_FTRACE + bool "enable/disable function tracing dynamically" + depends on FUNCTION_TRACER + depends on HAVE_DYNAMIC_FTRACE + default y + help + This option will modify all the calls to function tracing + dynamically (will patch them out of the binary image and + replace them with a No-Op instruction) on boot up. During + compile time, a table is made of all the locations that ftrace + can function trace, and this table is linked into the kernel + image. When this is enabled, functions can be individually + enabled, and the functions not enabled will not affect + performance of the system. + + See the files in /sys/kernel/debug/tracing: + available_filter_functions + set_ftrace_filter + set_ftrace_notrace + + This way a CONFIG_FUNCTION_TRACER kernel is slightly larger, but + otherwise has native performance as long as no tracing is active. + +config DYNAMIC_FTRACE_WITH_REGS + def_bool y + depends on DYNAMIC_FTRACE + depends on HAVE_DYNAMIC_FTRACE_WITH_REGS + +config DYNAMIC_FTRACE_WITH_DIRECT_CALLS + def_bool y + depends on DYNAMIC_FTRACE + depends on HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS + +config FUNCTION_PROFILER + bool "Kernel function profiler" + depends on FUNCTION_TRACER + default n + help + This option enables the kernel function profiler. A file is created + in debugfs called function_profile_enabled which defaults to zero. + When a 1 is echoed into this file profiling begins, and when a + zero is entered, profiling stops. A "functions" file is created in + the trace_stat directory; this file shows the list of functions that + have been hit and their counters. + + If in doubt, say N. + +config STACK_TRACER + bool "Trace max stack" + depends on HAVE_FUNCTION_TRACER + select FUNCTION_TRACER + select STACKTRACE + select KALLSYMS + help + This special tracer records the maximum stack footprint of the + kernel and displays it in /sys/kernel/debug/tracing/stack_trace. + + This tracer works by hooking into every function call that the + kernel executes, and keeping a maximum stack depth value and + stack-trace saved. If this is configured with DYNAMIC_FTRACE + then it will not have any overhead while the stack tracer + is disabled. + + To enable the stack tracer on bootup, pass in 'stacktrace' + on the kernel command line. + + The stack tracer can also be enabled or disabled via the + sysctl kernel.stack_tracer_enabled + + Say N if unsure. + config TRACE_PREEMPT_TOGGLE bool help @@ -282,6 +362,19 @@ config HWLAT_TRACER file. Every time a latency is greater than tracing_thresh, it will be recorded into the ring buffer. +config MMIOTRACE + bool "Memory mapped IO tracing" + depends on HAVE_MMIOTRACE_SUPPORT && PCI + select GENERIC_TRACER + help + Mmiotrace traces Memory Mapped I/O access and is meant for + debugging and reverse engineering. It is called from the ioremap + implementation and works via page faults. Tracing is disabled by + default and can be enabled at run-time. + + See Documentation/trace/mmiotrace.rst. + If you are not helping to develop drivers, say N. + config ENABLE_DEFAULT_TRACERS bool "Trace process context switches and events" depends on !GENERIC_TRACER @@ -410,30 +503,6 @@ config BRANCH_TRACER Say N if unsure. -config STACK_TRACER - bool "Trace max stack" - depends on HAVE_FUNCTION_TRACER - select FUNCTION_TRACER - select STACKTRACE - select KALLSYMS - help - This special tracer records the maximum stack footprint of the - kernel and displays it in /sys/kernel/debug/tracing/stack_trace. - - This tracer works by hooking into every function call that the - kernel executes, and keeping a maximum stack depth value and - stack-trace saved. If this is configured with DYNAMIC_FTRACE - then it will not have any overhead while the stack tracer - is disabled. - - To enable the stack tracer on bootup, pass in 'stacktrace' - on the kernel command line. - - The stack tracer can also be enabled or disabled via the - sysctl kernel.stack_tracer_enabled - - Say N if unsure. - config BLK_DEV_IO_TRACE bool "Support for tracing block IO actions" depends on SYSFS @@ -531,53 +600,6 @@ config DYNAMIC_EVENTS config PROBE_EVENTS def_bool n -config DYNAMIC_FTRACE - bool "enable/disable function tracing dynamically" - depends on FUNCTION_TRACER - depends on HAVE_DYNAMIC_FTRACE - default y - help - This option will modify all the calls to function tracing - dynamically (will patch them out of the binary image and - replace them with a No-Op instruction) on boot up. During - compile time, a table is made of all the locations that ftrace - can function trace, and this table is linked into the kernel - image. When this is enabled, functions can be individually - enabled, and the functions not enabled will not affect - performance of the system. - - See the files in /sys/kernel/debug/tracing: - available_filter_functions - set_ftrace_filter - set_ftrace_notrace - - This way a CONFIG_FUNCTION_TRACER kernel is slightly larger, but - otherwise has native performance as long as no tracing is active. - -config DYNAMIC_FTRACE_WITH_REGS - def_bool y - depends on DYNAMIC_FTRACE - depends on HAVE_DYNAMIC_FTRACE_WITH_REGS - -config DYNAMIC_FTRACE_WITH_DIRECT_CALLS - def_bool y - depends on DYNAMIC_FTRACE - depends on HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS - -config FUNCTION_PROFILER - bool "Kernel function profiler" - depends on FUNCTION_TRACER - default n - help - This option enables the kernel function profiler. A file is created - in debugfs called function_profile_enabled which defaults to zero. - When a 1 is echoed into this file profiling begins, and when a - zero is entered, profiling stops. A "functions" file is created in - the trace_stat directory; this file shows the list of functions that - have been hit and their counters. - - If in doubt, say N. - config BPF_KPROBE_OVERRIDE bool "Enable BPF programs to override a kprobed function" depends on BPF_EVENTS @@ -592,54 +614,6 @@ config FTRACE_MCOUNT_RECORD depends on DYNAMIC_FTRACE depends on HAVE_FTRACE_MCOUNT_RECORD -config FTRACE_SELFTEST - bool - -config FTRACE_STARTUP_TEST - bool "Perform a startup test on ftrace" - depends on GENERIC_TRACER - select FTRACE_SELFTEST - help - This option performs a series of startup tests on ftrace. On bootup - a series of tests are made to verify that the tracer is - functioning properly. It will do tests on all the configured - tracers of ftrace. - -config EVENT_TRACE_STARTUP_TEST - bool "Run selftest on trace events" - depends on FTRACE_STARTUP_TEST - default y - help - This option performs a test on all trace events in the system. - It basically just enables each event and runs some code that - will trigger events (not necessarily the event it enables) - This may take some time run as there are a lot of events. - -config EVENT_TRACE_TEST_SYSCALLS - bool "Run selftest on syscall events" - depends on EVENT_TRACE_STARTUP_TEST - help - This option will also enable testing every syscall event. - It only enables the event and disables it and runs various loads - with the event enabled. This adds a bit more time for kernel boot - up since it runs this on every system call defined. - - TBD - enable a way to actually call the syscalls as we test their - events - -config MMIOTRACE - bool "Memory mapped IO tracing" - depends on HAVE_MMIOTRACE_SUPPORT && PCI - select GENERIC_TRACER - help - Mmiotrace traces Memory Mapped I/O access and is meant for - debugging and reverse engineering. It is called from the ioremap - implementation and works via page faults. Tracing is disabled by - default and can be enabled at run-time. - - See Documentation/trace/mmiotrace.rst. - If you are not helping to develop drivers, say N. - config TRACING_MAP bool depends on ARCH_HAVE_NMI_SAFE_CMPXCHG @@ -680,16 +654,6 @@ config TRACE_EVENT_INJECT If unsure, say N. -config MMIOTRACE_TEST - tristate "Test module for mmiotrace" - depends on MMIOTRACE && m - help - This is a dumb module for testing mmiotrace. It is very dangerous - as it will write garbage to IO memory starting at a given address. - However, it should be safe to use on e.g. unused portion of VRAM. - - Say N, unless you absolutely know what you are doing. - config TRACEPOINT_BENCHMARK bool "Add tracepoint that benchmarks tracepoints" help @@ -736,6 +700,81 @@ config RING_BUFFER_BENCHMARK If unsure, say N. +config TRACE_EVAL_MAP_FILE + bool "Show eval mappings for trace events" + depends on TRACING + help + The "print fmt" of the trace events will show the enum/sizeof names + instead of their values. This can cause problems for user space tools + that use this string to parse the raw data as user space does not know + how to convert the string to its value. + + To fix this, there's a special macro in the kernel that can be used + to convert an enum/sizeof into its value. If this macro is used, then + the print fmt strings will be converted to their values. + + If something does not get converted properly, this option can be + used to show what enums/sizeof the kernel tried to convert. + + This option is for debugging the conversions. A file is created + in the tracing directory called "eval_map" that will show the + names matched with their values and what trace event system they + belong too. + + Normally, the mapping of the strings to values will be freed after + boot up or module load. With this option, they will not be freed, as + they are needed for the "eval_map" file. Enabling this option will + increase the memory footprint of the running kernel. + + If unsure, say N. + +config GCOV_PROFILE_FTRACE + bool "Enable GCOV profiling on ftrace subsystem" + depends on GCOV_KERNEL + help + Enable GCOV profiling on ftrace subsystem for checking + which functions/lines are tested. + + If unsure, say N. + + Note that on a kernel compiled with this config, ftrace will + run significantly slower. + +config FTRACE_SELFTEST + bool + +config FTRACE_STARTUP_TEST + bool "Perform a startup test on ftrace" + depends on GENERIC_TRACER + select FTRACE_SELFTEST + help + This option performs a series of startup tests on ftrace. On bootup + a series of tests are made to verify that the tracer is + functioning properly. It will do tests on all the configured + tracers of ftrace. + +config EVENT_TRACE_STARTUP_TEST + bool "Run selftest on trace events" + depends on FTRACE_STARTUP_TEST + default y + help + This option performs a test on all trace events in the system. + It basically just enables each event and runs some code that + will trigger events (not necessarily the event it enables) + This may take some time run as there are a lot of events. + +config EVENT_TRACE_TEST_SYSCALLS + bool "Run selftest on syscall events" + depends on EVENT_TRACE_STARTUP_TEST + help + This option will also enable testing every syscall event. + It only enables the event and disables it and runs various loads + with the event enabled. This adds a bit more time for kernel boot + up since it runs this on every system call defined. + + TBD - enable a way to actually call the syscalls as we test their + events + config RING_BUFFER_STARTUP_TEST bool "Ring buffer startup self test" depends on RING_BUFFER @@ -759,8 +798,18 @@ config RING_BUFFER_STARTUP_TEST If unsure, say N +config MMIOTRACE_TEST + tristate "Test module for mmiotrace" + depends on MMIOTRACE && m + help + This is a dumb module for testing mmiotrace. It is very dangerous + as it will write garbage to IO memory starting at a given address. + However, it should be safe to use on e.g. unused portion of VRAM. + + Say N, unless you absolutely know what you are doing. + config PREEMPTIRQ_DELAY_TEST - tristate "Preempt / IRQ disable delay thread to test latency tracers" + tristate "Test module to create a preempt / IRQ disable delay thread to test latency tracers" depends on m help Select this option to build a test module that can help test latency @@ -774,45 +823,30 @@ config PREEMPTIRQ_DELAY_TEST If unsure, say N -config TRACE_EVAL_MAP_FILE - bool "Show eval mappings for trace events" - depends on TRACING - help - The "print fmt" of the trace events will show the enum/sizeof names - instead of their values. This can cause problems for user space tools - that use this string to parse the raw data as user space does not know - how to convert the string to its value. - - To fix this, there's a special macro in the kernel that can be used - to convert an enum/sizeof into its value. If this macro is used, then - the print fmt strings will be converted to their values. - - If something does not get converted properly, this option can be - used to show what enums/sizeof the kernel tried to convert. - - This option is for debugging the conversions. A file is created - in the tracing directory called "eval_map" that will show the - names matched with their values and what trace event system they - belong too. +config SYNTH_EVENT_GEN_TEST + tristate "Test module for in-kernel synthetic event generation" + depends on HIST_TRIGGERS + help + This option creates a test module to check the base + functionality of in-kernel synthetic event definition and + generation. - Normally, the mapping of the strings to values will be freed after - boot up or module load. With this option, they will not be freed, as - they are needed for the "eval_map" file. Enabling this option will - increase the memory footprint of the running kernel. + To test, insert the module, and then check the trace buffer + for the generated sample events. - If unsure, say N. + If unsure, say N. -config GCOV_PROFILE_FTRACE - bool "Enable GCOV profiling on ftrace subsystem" - depends on GCOV_KERNEL +config KPROBE_EVENT_GEN_TEST + tristate "Test module for in-kernel kprobe event generation" + depends on KPROBE_EVENTS help - Enable GCOV profiling on ftrace subsystem for checking - which functions/lines are tested. + This option creates a test module to check the base + functionality of in-kernel kprobe event definition. - If unsure, say N. + To test, insert the module, and then check the trace buffer + for the generated kprobe events. - Note that on a kernel compiled with this config, ftrace will - run significantly slower. + If unsure, say N. endif # FTRACE diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile index 0e63db62225f..f9dcd19165fa 100644 --- a/kernel/trace/Makefile +++ b/kernel/trace/Makefile @@ -44,6 +44,8 @@ obj-$(CONFIG_TRACING) += trace_stat.o obj-$(CONFIG_TRACING) += trace_printk.o obj-$(CONFIG_TRACING_MAP) += tracing_map.o obj-$(CONFIG_PREEMPTIRQ_DELAY_TEST) += preemptirq_delay_test.o +obj-$(CONFIG_SYNTH_EVENT_GEN_TEST) += synth_event_gen_test.o +obj-$(CONFIG_KPROBE_EVENT_GEN_TEST) += kprobe_event_gen_test.o obj-$(CONFIG_CONTEXT_SWITCH_TRACER) += trace_sched_switch.o obj-$(CONFIG_FUNCTION_TRACER) += trace_functions.o obj-$(CONFIG_PREEMPTIRQ_TRACEPOINTS) += trace_preemptirq.o @@ -83,6 +85,7 @@ endif obj-$(CONFIG_DYNAMIC_EVENTS) += trace_dynevent.o obj-$(CONFIG_PROBE_EVENTS) += trace_probe.o obj-$(CONFIG_UPROBE_EVENTS) += trace_uprobe.o +obj-$(CONFIG_BOOTTIME_TRACING) += trace_boot.o obj-$(CONFIG_TRACEPOINT_BENCHMARK) += trace_benchmark.o diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c index 475e29498bca..0735ae8545d8 100644 --- a/kernel/trace/blktrace.c +++ b/kernel/trace/blktrace.c @@ -68,14 +68,14 @@ static void trace_note(struct blk_trace *bt, pid_t pid, int action, { struct blk_io_trace *t; struct ring_buffer_event *event = NULL; - struct ring_buffer *buffer = NULL; + struct trace_buffer *buffer = NULL; int pc = 0; int cpu = smp_processor_id(); bool blk_tracer = blk_tracer_enabled; ssize_t cgid_len = cgid ? sizeof(cgid) : 0; if (blk_tracer) { - buffer = blk_tr->trace_buffer.buffer; + buffer = blk_tr->array_buffer.buffer; pc = preempt_count(); event = trace_buffer_lock_reserve(buffer, TRACE_BLK, sizeof(*t) + len + cgid_len, @@ -215,7 +215,7 @@ static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes, { struct task_struct *tsk = current; struct ring_buffer_event *event = NULL; - struct ring_buffer *buffer = NULL; + struct trace_buffer *buffer = NULL; struct blk_io_trace *t; unsigned long flags = 0; unsigned long *sequence; @@ -248,7 +248,7 @@ static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes, if (blk_tracer) { tracing_record_cmdline(current); - buffer = blk_tr->trace_buffer.buffer; + buffer = blk_tr->array_buffer.buffer; pc = preempt_count(); event = trace_buffer_lock_reserve(buffer, TRACE_BLK, sizeof(*t) + pdu_len + cgid_len, diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 9bf1f2cd515e..3f7ee102868a 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -62,8 +62,6 @@ }) /* hash bits for specific function selection */ -#define FTRACE_HASH_BITS 7 -#define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS) #define FTRACE_HASH_DEFAULT_BITS 10 #define FTRACE_HASH_MAX_BITS 12 @@ -146,7 +144,7 @@ static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip, { struct trace_array *tr = op->private; - if (tr && this_cpu_read(tr->trace_buffer.data->ftrace_ignore_pid)) + if (tr && this_cpu_read(tr->array_buffer.data->ftrace_ignore_pid)) return; op->saved_func(ip, parent_ip, op, regs); @@ -1103,9 +1101,6 @@ struct ftrace_page { #define ENTRY_SIZE sizeof(struct dyn_ftrace) #define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE) -/* estimate from running different kernels */ -#define NR_TO_INIT 10000 - static struct ftrace_page *ftrace_pages_start; static struct ftrace_page *ftrace_pages; @@ -5464,7 +5459,7 @@ static void __init set_ftrace_early_graph(char *buf, int enable) struct ftrace_hash *hash; hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS); - if (WARN_ON(!hash)) + if (MEM_FAIL(!hash, "Failed to allocate hash\n")) return; while (buf) { @@ -5596,8 +5591,8 @@ static const struct file_operations ftrace_notrace_fops = { static DEFINE_MUTEX(graph_lock); -struct ftrace_hash *ftrace_graph_hash = EMPTY_HASH; -struct ftrace_hash *ftrace_graph_notrace_hash = EMPTY_HASH; +struct ftrace_hash __rcu *ftrace_graph_hash = EMPTY_HASH; +struct ftrace_hash __rcu *ftrace_graph_notrace_hash = EMPTY_HASH; enum graph_filter_type { GRAPH_FILTER_NOTRACE = 0, @@ -5872,8 +5867,15 @@ ftrace_graph_release(struct inode *inode, struct file *file) mutex_unlock(&graph_lock); - /* Wait till all users are no longer using the old hash */ - synchronize_rcu(); + /* + * We need to do a hard force of sched synchronization. + * This is because we use preempt_disable() to do RCU, but + * the function tracers can be called where RCU is not watching + * (like before user_exit()). We can not rely on the RCU + * infrastructure to do the synchronization, thus we must do it + * ourselves. + */ + schedule_on_each_cpu(ftrace_sync); free_ftrace_hash(old_hash); } @@ -6596,7 +6598,7 @@ static void add_to_clear_hash_list(struct list_head *clear_list, func = kmalloc(sizeof(*func), GFP_KERNEL); if (!func) { - WARN_ONCE(1, "alloc failure, ftrace filter could be stale\n"); + MEM_FAIL(1, "alloc failure, ftrace filter could be stale\n"); return; } @@ -6922,7 +6924,7 @@ ftrace_filter_pid_sched_switch_probe(void *data, bool preempt, pid_list = rcu_dereference_sched(tr->function_pids); - this_cpu_write(tr->trace_buffer.data->ftrace_ignore_pid, + this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid, trace_ignore_this_task(pid_list, next)); } @@ -6976,7 +6978,7 @@ static void clear_ftrace_pids(struct trace_array *tr) unregister_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr); for_each_possible_cpu(cpu) - per_cpu_ptr(tr->trace_buffer.data, cpu)->ftrace_ignore_pid = false; + per_cpu_ptr(tr->array_buffer.data, cpu)->ftrace_ignore_pid = false; rcu_assign_pointer(tr->function_pids, NULL); @@ -7031,9 +7033,10 @@ static void *fpid_next(struct seq_file *m, void *v, loff_t *pos) struct trace_array *tr = m->private; struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_pids); - if (v == FTRACE_NO_PIDS) + if (v == FTRACE_NO_PIDS) { + (*pos)++; return NULL; - + } return trace_pid_next(pid_list, v, pos); } @@ -7100,7 +7103,7 @@ static void ignore_task_cpu(void *data) pid_list = rcu_dereference_protected(tr->function_pids, mutex_is_locked(&ftrace_lock)); - this_cpu_write(tr->trace_buffer.data->ftrace_ignore_pid, + this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid, trace_ignore_this_task(pid_list, current)); } diff --git a/kernel/trace/kprobe_event_gen_test.c b/kernel/trace/kprobe_event_gen_test.c new file mode 100644 index 000000000000..18b0f1cbb947 --- /dev/null +++ b/kernel/trace/kprobe_event_gen_test.c @@ -0,0 +1,225 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Test module for in-kernel kprobe event creation and generation. + * + * Copyright (C) 2019 Tom Zanussi <zanussi@kernel.org> + */ + +#include <linux/module.h> +#include <linux/trace_events.h> + +/* + * This module is a simple test of basic functionality for in-kernel + * kprobe/kretprobe event creation. The first test uses + * kprobe_event_gen_cmd_start(), kprobe_event_add_fields() and + * kprobe_event_gen_cmd_end() to create a kprobe event, which is then + * enabled in order to generate trace output. The second creates a + * kretprobe event using kretprobe_event_gen_cmd_start() and + * kretprobe_event_gen_cmd_end(), and is also then enabled. + * + * To test, select CONFIG_KPROBE_EVENT_GEN_TEST and build the module. + * Then: + * + * # insmod kernel/trace/kprobe_event_gen_test.ko + * # cat /sys/kernel/debug/tracing/trace + * + * You should see many instances of the "gen_kprobe_test" and + * "gen_kretprobe_test" events in the trace buffer. + * + * To remove the events, remove the module: + * + * # rmmod kprobe_event_gen_test + * + */ + +static struct trace_event_file *gen_kprobe_test; +static struct trace_event_file *gen_kretprobe_test; + +/* + * Test to make sure we can create a kprobe event, then add more + * fields. + */ +static int __init test_gen_kprobe_cmd(void) +{ + struct dynevent_cmd cmd; + char *buf; + int ret; + + /* Create a buffer to hold the generated command */ + buf = kzalloc(MAX_DYNEVENT_CMD_LEN, GFP_KERNEL); + if (!buf) + return -ENOMEM; + + /* Before generating the command, initialize the cmd object */ + kprobe_event_cmd_init(&cmd, buf, MAX_DYNEVENT_CMD_LEN); + + /* + * Define the gen_kprobe_test event with the first 2 kprobe + * fields. + */ + ret = kprobe_event_gen_cmd_start(&cmd, "gen_kprobe_test", + "do_sys_open", + "dfd=%ax", "filename=%dx"); + if (ret) + goto free; + + /* Use kprobe_event_add_fields to add the rest of the fields */ + + ret = kprobe_event_add_fields(&cmd, "flags=%cx", "mode=+4($stack)"); + if (ret) + goto free; + + /* + * This actually creates the event. + */ + ret = kprobe_event_gen_cmd_end(&cmd); + if (ret) + goto free; + + /* + * Now get the gen_kprobe_test event file. We need to prevent + * the instance and event from disappearing from underneath + * us, which trace_get_event_file() does (though in this case + * we're using the top-level instance which never goes away). + */ + gen_kprobe_test = trace_get_event_file(NULL, "kprobes", + "gen_kprobe_test"); + if (IS_ERR(gen_kprobe_test)) { + ret = PTR_ERR(gen_kprobe_test); + goto delete; + } + + /* Enable the event or you won't see anything */ + ret = trace_array_set_clr_event(gen_kprobe_test->tr, + "kprobes", "gen_kprobe_test", true); + if (ret) { + trace_put_event_file(gen_kprobe_test); + goto delete; + } + out: + return ret; + delete: + /* We got an error after creating the event, delete it */ + ret = kprobe_event_delete("gen_kprobe_test"); + free: + kfree(buf); + + goto out; +} + +/* + * Test to make sure we can create a kretprobe event. + */ +static int __init test_gen_kretprobe_cmd(void) +{ + struct dynevent_cmd cmd; + char *buf; + int ret; + + /* Create a buffer to hold the generated command */ + buf = kzalloc(MAX_DYNEVENT_CMD_LEN, GFP_KERNEL); + if (!buf) + return -ENOMEM; + + /* Before generating the command, initialize the cmd object */ + kprobe_event_cmd_init(&cmd, buf, MAX_DYNEVENT_CMD_LEN); + + /* + * Define the kretprobe event. + */ + ret = kretprobe_event_gen_cmd_start(&cmd, "gen_kretprobe_test", + "do_sys_open", + "$retval"); + if (ret) + goto free; + + /* + * This actually creates the event. + */ + ret = kretprobe_event_gen_cmd_end(&cmd); + if (ret) + goto free; + + /* + * Now get the gen_kretprobe_test event file. We need to + * prevent the instance and event from disappearing from + * underneath us, which trace_get_event_file() does (though in + * this case we're using the top-level instance which never + * goes away). + */ + gen_kretprobe_test = trace_get_event_file(NULL, "kprobes", + "gen_kretprobe_test"); + if (IS_ERR(gen_kretprobe_test)) { + ret = PTR_ERR(gen_kretprobe_test); + goto delete; + } + + /* Enable the event or you won't see anything */ + ret = trace_array_set_clr_event(gen_kretprobe_test->tr, + "kprobes", "gen_kretprobe_test", true); + if (ret) { + trace_put_event_file(gen_kretprobe_test); + goto delete; + } + out: + return ret; + delete: + /* We got an error after creating the event, delete it */ + ret = kprobe_event_delete("gen_kretprobe_test"); + free: + kfree(buf); + + goto out; +} + +static int __init kprobe_event_gen_test_init(void) +{ + int ret; + + ret = test_gen_kprobe_cmd(); + if (ret) + return ret; + + ret = test_gen_kretprobe_cmd(); + if (ret) { + WARN_ON(trace_array_set_clr_event(gen_kretprobe_test->tr, + "kprobes", + "gen_kretprobe_test", false)); + trace_put_event_file(gen_kretprobe_test); + WARN_ON(kprobe_event_delete("gen_kretprobe_test")); + } + + return ret; +} + +static void __exit kprobe_event_gen_test_exit(void) +{ + /* Disable the event or you can't remove it */ + WARN_ON(trace_a |