diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/trace/trace.h | 4 | ||||
| -rw-r--r-- | kernel/trace/trace_syscalls.c | 42 |
2 files changed, 34 insertions, 12 deletions
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 12d1a61..9c27cda 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -192,8 +192,8 @@ struct trace_array { #ifdef CONFIG_FTRACE_SYSCALLS int sys_refcount_enter; int sys_refcount_exit; - DECLARE_BITMAP(enabled_enter_syscalls, NR_syscalls); - DECLARE_BITMAP(enabled_exit_syscalls, NR_syscalls); + struct ftrace_event_file *enter_syscall_files[NR_syscalls]; + struct ftrace_event_file *exit_syscall_files[NR_syscalls]; #endif int stop_count; int clock_id; diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c index 32644ee..e4b6d11 100644 --- a/kernel/trace/trace_syscalls.c +++ b/kernel/trace/trace_syscalls.c @@ -302,6 +302,7 @@ static int __init syscall_exit_define_fields(struct ftrace_event_call *call) static void ftrace_syscall_enter(void *data, struct pt_regs *regs, long id) { struct trace_array *tr = data; + struct ftrace_event_file *ftrace_file; struct syscall_trace_enter *entry; struct syscall_metadata *sys_data; struct ring_buffer_event *event; @@ -314,7 +315,13 @@ static void ftrace_syscall_enter(void *data, struct pt_regs *regs, long id) syscall_nr = trace_get_syscall_nr(current, regs); if (syscall_nr < 0) return; - if (!test_bit(syscall_nr, tr->enabled_enter_syscalls)) + + /* Here we're inside tp handler's rcu_read_lock_sched (__DO_TRACE) */ + ftrace_file = rcu_dereference_sched(tr->enter_syscall_files[syscall_nr]); + if (!ftrace_file) + return; + + if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &ftrace_file->flags)) return; sys_data = syscall_nr_to_meta(syscall_nr); @@ -336,8 +343,7 @@ static void ftrace_syscall_enter(void *data, struct pt_regs *regs, long id) entry->nr = syscall_nr; syscall_get_arguments(current, regs, 0, sys_data->nb_args, entry->args); - if (!call_filter_check_discard(sys_data->enter_event, entry, - buffer, event)) + if (!filter_check_discard(ftrace_file, entry, buffer, event)) trace_current_buffer_unlock_commit(buffer, event, irq_flags, pc); } @@ -345,6 +351,7 @@ static void ftrace_syscall_enter(void *data, struct pt_regs *regs, long id) static void ftrace_syscall_exit(void *data, struct pt_regs *regs, long ret) { struct trace_array *tr = data; + struct ftrace_event_file *ftrace_file; struct syscall_trace_exit *entry; struct syscall_metadata *sys_data; struct ring_buffer_event *event; @@ -356,7 +363,13 @@ static void ftrace_syscall_exit(void *data, struct pt_regs *regs, long ret) syscall_nr = trace_get_syscall_nr(current, regs); if (syscall_nr < 0) return; - if (!test_bit(syscall_nr, tr->enabled_exit_syscalls)) + + /* Here we're inside tp handler's rcu_read_lock_sched (__DO_TRACE()) */ + ftrace_file = rcu_dereference_sched(tr->exit_syscall_files[syscall_nr]); + if (!ftrace_file) + return; + + if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &ftrace_file->flags)) return; sys_data = syscall_nr_to_meta(syscall_nr); @@ -377,8 +390,7 @@ static void ftrace_syscall_exit(void *data, struct pt_regs *regs, long ret) entry->nr = syscall_nr; entry->ret = syscall_get_return_value(current, regs); - if (!call_filter_check_discard(sys_data->exit_event, entry, - buffer, event)) + if (!filter_check_discard(ftrace_file, entry, buffer, event)) trace_current_buffer_unlock_commit(buffer, event, irq_flags, pc); } @@ -397,7 +409,7 @@ static int reg_event_syscall_enter(struct ftrace_event_file *file, if (!tr->sys_refcount_enter) ret = register_trace_sys_enter(ftrace_syscall_enter, tr); if (!ret) { - set_bit(num, tr->enabled_enter_syscalls); + rcu_assign_pointer(tr->enter_syscall_files[num], file); tr->sys_refcount_enter++; } mutex_unlock(&syscall_trace_lock); @@ -415,10 +427,15 @@ static void unreg_event_syscall_enter(struct ftrace_event_file *file, return; mutex_lock(&syscall_trace_lock); tr->sys_refcount_enter--; - clear_bit(num, tr->enabled_enter_syscalls); + rcu_assign_pointer(tr->enter_syscall_files[num], NULL); if (!tr->sys_refcount_enter) unregister_trace_sys_enter(ftrace_syscall_enter, tr); mutex_unlock(&syscall_trace_lock); + /* + * Callers expect the event to be completely disabled on + * return, so wait for current handlers to finish. + */ + synchronize_sched(); } static int reg_event_syscall_exit(struct ftrace_event_file *file, @@ -435,7 +452,7 @@ static int reg_event_syscall_exit(struct ftrace_event_file *file, if (!tr->sys_refcount_exit) ret = register_trace_sys_exit(ftrace_syscall_exit, tr); if (!ret) { - set_bit(num, tr->enabled_exit_syscalls); + rcu_assign_pointer(tr->exit_syscall_files[num], file); tr->sys_refcount_exit++; } mutex_unlock(&syscall_trace_lock); @@ -453,10 +470,15 @@ static void unreg_event_syscall_exit(struct ftrace_event_file *file, return; mutex_lock(&syscall_trace_lock); tr->sys_refcount_exit--; - clear_bit(num, tr->enabled_exit_syscalls); + rcu_assign_pointer(tr->exit_syscall_files[num], NULL); if (!tr->sys_refcount_exit) unregister_trace_sys_exit(ftrace_syscall_exit, tr); mutex_unlock(&syscall_trace_lock); + /* + * Callers expect the event to be completely disabled on + * return, so wait for current handlers to finish. + */ + synchronize_sched(); } static int __init init_syscall_trace(struct ftrace_event_call *call) |
