tracing: Add trace events for each syscall entry/exit
Layer Frederic's syscall tracer on tracepoints. We create trace events via hooking into the SYSCALL_DEFINE macros. This allows us to individually toggle syscall entry and exit points on/off. Signed-off-by: Jason Baron <jbaron@redhat.com> Cc: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Cc: Jiaying Zhang <jiayingz@google.com> Cc: Martin Bligh <mbligh@google.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Masami Hiramatsu <mhiramat@redhat.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
This commit is contained in:
Jason Baron
Frederic Weisbecker
Родитель
69fd4f0eb2
Коммит
fb34a08c34
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@ -64,6 +64,7 @@ struct perf_counter_attr;
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#include <linux/sem.h>
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#include <asm/siginfo.h>
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#include <asm/signal.h>
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#include <linux/unistd.h>
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#include <linux/quota.h>
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#include <linux/key.h>
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#include <trace/syscall.h>
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@ -112,6 +113,59 @@ struct perf_counter_attr;
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#define __SC_STR_TDECL5(t, a, ...) #t, __SC_STR_TDECL4(__VA_ARGS__)
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#define __SC_STR_TDECL6(t, a, ...) #t, __SC_STR_TDECL5(__VA_ARGS__)
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#define SYSCALL_TRACE_ENTER_EVENT(sname) \
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static struct ftrace_event_call event_enter_##sname; \
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static int init_enter_##sname(void) \
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{ \
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int num; \
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num = syscall_name_to_nr("sys"#sname); \
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if (num < 0) \
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return -ENOSYS; \
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register_ftrace_event(&event_syscall_enter); \
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INIT_LIST_HEAD(&event_enter_##sname.fields); \
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init_preds(&event_enter_##sname); \
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return 0; \
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} \
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static struct ftrace_event_call __used \
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__attribute__((__aligned__(4))) \
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__attribute__((section("_ftrace_events"))) \
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event_enter_##sname = { \
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.name = "sys_enter"#sname, \
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.system = "syscalls", \
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.event = &event_syscall_enter, \
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.raw_init = init_enter_##sname, \
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.regfunc = reg_event_syscall_enter, \
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.unregfunc = unreg_event_syscall_enter, \
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.data = "sys"#sname, \
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}
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#define SYSCALL_TRACE_EXIT_EVENT(sname) \
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static struct ftrace_event_call event_exit_##sname; \
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static int init_exit_##sname(void) \
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{ \
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int num; \
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num = syscall_name_to_nr("sys"#sname); \
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if (num < 0) \
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return -ENOSYS; \
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register_ftrace_event(&event_syscall_exit); \
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INIT_LIST_HEAD(&event_exit_##sname.fields); \
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init_preds(&event_exit_##sname); \
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return 0; \
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} \
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static struct ftrace_event_call __used \
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__attribute__((__aligned__(4))) \
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__attribute__((section("_ftrace_events"))) \
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event_exit_##sname = { \
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.name = "sys_exit"#sname, \
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.system = "syscalls", \
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.event = &event_syscall_exit, \
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.raw_init = init_exit_##sname, \
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.regfunc = reg_event_syscall_exit, \
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.unregfunc = unreg_event_syscall_exit, \
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.data = "sys"#sname, \
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}
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#define SYSCALL_METADATA(sname, nb) \
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static const struct syscall_metadata __used \
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__attribute__((__aligned__(4))) \
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@ -121,7 +175,9 @@ struct perf_counter_attr;
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.nb_args = nb, \
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.types = types_##sname, \
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.args = args_##sname, \
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}
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}; \
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SYSCALL_TRACE_ENTER_EVENT(sname); \
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SYSCALL_TRACE_EXIT_EVENT(sname);
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#define SYSCALL_DEFINE0(sname) \
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static const struct syscall_metadata __used \
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@ -131,8 +187,9 @@ struct perf_counter_attr;
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.name = "sys_"#sname, \
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.nb_args = 0, \
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}; \
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SYSCALL_TRACE_ENTER_EVENT(_##sname); \
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SYSCALL_TRACE_EXIT_EVENT(_##sname); \
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asmlinkage long sys_##sname(void)
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#else
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#define SYSCALL_DEFINE0(name) asmlinkage long sys_##name(void)
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#endif
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@ -2,6 +2,8 @@
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#define _TRACE_SYSCALL_H
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#include <linux/tracepoint.h>
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#include <linux/unistd.h>
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#include <linux/ftrace_event.h>
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#include <asm/ptrace.h>
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@ -40,15 +42,13 @@ struct syscall_metadata {
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#ifdef CONFIG_FTRACE_SYSCALLS
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extern struct syscall_metadata *syscall_nr_to_meta(int nr);
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extern void start_ftrace_syscalls(void);
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extern void stop_ftrace_syscalls(void);
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extern void ftrace_syscall_enter(struct pt_regs *regs);
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extern void ftrace_syscall_exit(struct pt_regs *regs);
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#else
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static inline void start_ftrace_syscalls(void) { }
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static inline void stop_ftrace_syscalls(void) { }
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static inline void ftrace_syscall_enter(struct pt_regs *regs) { }
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static inline void ftrace_syscall_exit(struct pt_regs *regs) { }
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extern int syscall_name_to_nr(char *name);
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extern struct trace_event event_syscall_enter;
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extern struct trace_event event_syscall_exit;
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extern int reg_event_syscall_enter(void *ptr);
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extern void unreg_event_syscall_enter(void *ptr);
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extern int reg_event_syscall_exit(void *ptr);
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extern void unreg_event_syscall_exit(void *ptr);
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#endif
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#endif /* _TRACE_SYSCALL_H */
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@ -1,15 +1,16 @@
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#include <trace/syscall.h>
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#include <linux/kernel.h>
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#include <linux/ftrace.h>
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#include <asm/syscall.h>
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#include "trace_output.h"
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#include "trace.h"
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/* Keep a counter of the syscall tracing users */
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static int refcount;
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/* Prevent from races on thread flags toggling */
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static DEFINE_MUTEX(syscall_trace_lock);
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static int sys_refcount_enter;
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static int sys_refcount_exit;
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static DECLARE_BITMAP(enabled_enter_syscalls, FTRACE_SYSCALL_MAX);
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static DECLARE_BITMAP(enabled_exit_syscalls, FTRACE_SYSCALL_MAX);
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/* Option to display the parameters types */
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enum {
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@ -95,53 +96,7 @@ print_syscall_exit(struct trace_iterator *iter, int flags)
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return TRACE_TYPE_HANDLED;
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}
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void start_ftrace_syscalls(void)
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{
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unsigned long flags;
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struct task_struct *g, *t;
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mutex_lock(&syscall_trace_lock);
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/* Don't enable the flag on the tasks twice */
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if (++refcount != 1)
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goto unlock;
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read_lock_irqsave(&tasklist_lock, flags);
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do_each_thread(g, t) {
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set_tsk_thread_flag(t, TIF_SYSCALL_FTRACE);
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} while_each_thread(g, t);
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read_unlock_irqrestore(&tasklist_lock, flags);
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unlock:
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mutex_unlock(&syscall_trace_lock);
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}
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void stop_ftrace_syscalls(void)
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{
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unsigned long flags;
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struct task_struct *g, *t;
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mutex_lock(&syscall_trace_lock);
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/* There are perhaps still some users */
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if (--refcount)
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goto unlock;
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read_lock_irqsave(&tasklist_lock, flags);
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do_each_thread(g, t) {
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clear_tsk_thread_flag(t, TIF_SYSCALL_FTRACE);
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} while_each_thread(g, t);
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read_unlock_irqrestore(&tasklist_lock, flags);
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unlock:
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mutex_unlock(&syscall_trace_lock);
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}
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void ftrace_syscall_enter(struct pt_regs *regs)
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void ftrace_syscall_enter(struct pt_regs *regs, long id)
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{
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struct syscall_trace_enter *entry;
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struct syscall_metadata *sys_data;
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@ -150,6 +105,8 @@ void ftrace_syscall_enter(struct pt_regs *regs)
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int syscall_nr;
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syscall_nr = syscall_get_nr(current, regs);
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if (!test_bit(syscall_nr, enabled_enter_syscalls))
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return;
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sys_data = syscall_nr_to_meta(syscall_nr);
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if (!sys_data)
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@ -170,7 +127,7 @@ void ftrace_syscall_enter(struct pt_regs *regs)
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trace_wake_up();
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}
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void ftrace_syscall_exit(struct pt_regs *regs)
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void ftrace_syscall_exit(struct pt_regs *regs, long ret)
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{
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struct syscall_trace_exit *entry;
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struct syscall_metadata *sys_data;
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@ -178,6 +135,8 @@ void ftrace_syscall_exit(struct pt_regs *regs)
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int syscall_nr;
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syscall_nr = syscall_get_nr(current, regs);
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if (!test_bit(syscall_nr, enabled_exit_syscalls))
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return;
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sys_data = syscall_nr_to_meta(syscall_nr);
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if (!sys_data)
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@ -196,54 +155,94 @@ void ftrace_syscall_exit(struct pt_regs *regs)
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trace_wake_up();
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}
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static int init_syscall_tracer(struct trace_array *tr)
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int reg_event_syscall_enter(void *ptr)
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{
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start_ftrace_syscalls();
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int ret = 0;
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int num;
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char *name;
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return 0;
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}
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static void reset_syscall_tracer(struct trace_array *tr)
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{
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stop_ftrace_syscalls();
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tracing_reset_online_cpus(tr);
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}
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static struct trace_event syscall_enter_event = {
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.type = TRACE_SYSCALL_ENTER,
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.trace = print_syscall_enter,
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};
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static struct trace_event syscall_exit_event = {
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.type = TRACE_SYSCALL_EXIT,
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.trace = print_syscall_exit,
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};
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static struct tracer syscall_tracer __read_mostly = {
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.name = "syscall",
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.init = init_syscall_tracer,
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.reset = reset_syscall_tracer,
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.flags = &syscalls_flags,
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};
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__init int register_ftrace_syscalls(void)
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{
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int ret;
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ret = register_ftrace_event(&syscall_enter_event);
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if (!ret) {
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printk(KERN_WARNING "event %d failed to register\n",
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syscall_enter_event.type);
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WARN_ON_ONCE(1);
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name = (char *)ptr;
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num = syscall_name_to_nr(name);
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if (num < 0 || num >= FTRACE_SYSCALL_MAX)
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return -ENOSYS;
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mutex_lock(&syscall_trace_lock);
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if (!sys_refcount_enter)
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ret = register_trace_syscall_enter(ftrace_syscall_enter);
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if (ret) {
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pr_info("event trace: Could not activate"
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"syscall entry trace point");
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} else {
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set_bit(num, enabled_enter_syscalls);
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sys_refcount_enter++;
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}
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ret = register_ftrace_event(&syscall_exit_event);
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if (!ret) {
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printk(KERN_WARNING "event %d failed to register\n",
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syscall_exit_event.type);
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WARN_ON_ONCE(1);
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}
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return register_tracer(&syscall_tracer);
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mutex_unlock(&syscall_trace_lock);
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return ret;
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}
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device_initcall(register_ftrace_syscalls);
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void unreg_event_syscall_enter(void *ptr)
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{
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int num;
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char *name;
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name = (char *)ptr;
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num = syscall_name_to_nr(name);
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if (num < 0 || num >= FTRACE_SYSCALL_MAX)
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return;
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mutex_lock(&syscall_trace_lock);
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sys_refcount_enter--;
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clear_bit(num, enabled_enter_syscalls);
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if (!sys_refcount_enter)
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unregister_trace_syscall_enter(ftrace_syscall_enter);
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mutex_unlock(&syscall_trace_lock);
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}
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int reg_event_syscall_exit(void *ptr)
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{
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int ret = 0;
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int num;
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char *name;
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name = (char *)ptr;
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num = syscall_name_to_nr(name);
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if (num < 0 || num >= FTRACE_SYSCALL_MAX)
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return -ENOSYS;
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mutex_lock(&syscall_trace_lock);
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if (!sys_refcount_exit)
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ret = register_trace_syscall_exit(ftrace_syscall_exit);
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if (ret) {
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pr_info("event trace: Could not activate"
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"syscall exit trace point");
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} else {
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set_bit(num, enabled_exit_syscalls);
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sys_refcount_exit++;
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}
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mutex_unlock(&syscall_trace_lock);
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return ret;
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}
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void unreg_event_syscall_exit(void *ptr)
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{
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int num;
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char *name;
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name = (char *)ptr;
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num = syscall_name_to_nr(name);
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if (num < 0 || num >= FTRACE_SYSCALL_MAX)
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return;
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mutex_lock(&syscall_trace_lock);
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sys_refcount_exit--;
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clear_bit(num, enabled_exit_syscalls);
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if (!sys_refcount_exit)
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unregister_trace_syscall_exit(ftrace_syscall_exit);
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mutex_unlock(&syscall_trace_lock);
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}
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struct trace_event event_syscall_enter = {
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.trace = print_syscall_enter,
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.type = TRACE_SYSCALL_ENTER
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};
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struct trace_event event_syscall_exit = {
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.trace = print_syscall_exit,
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.type = TRACE_SYSCALL_EXIT
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};
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