diff options
Diffstat (limited to 'kernel/tracepoint.c')
| -rw-r--r-- | kernel/tracepoint.c | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c index 9e0a36f0e2a9..1a6a453b7efb 100644 --- a/kernel/tracepoint.c +++ b/kernel/tracepoint.c @@ -243,6 +243,11 @@ static void set_tracepoint(struct tracepoint_entry **entry, { WARN_ON(strcmp((*entry)->name, elem->name) != 0); + if (elem->regfunc && !elem->state && active) + elem->regfunc(); + else if (elem->unregfunc && elem->state && !active) + elem->unregfunc(); + /* * rcu_assign_pointer has a smp_wmb() which makes sure that the new * probe callbacks array is consistent before setting a pointer to it. @@ -262,6 +267,9 @@ static void set_tracepoint(struct tracepoint_entry **entry, */ static void disable_tracepoint(struct tracepoint *elem) { + if (elem->unregfunc && elem->state) + elem->unregfunc(); + elem->state = 0; rcu_assign_pointer(elem->funcs, NULL); } @@ -578,7 +586,7 @@ __initcall(init_tracepoints); #ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS -static DEFINE_MUTEX(regfunc_mutex); +/* NB: reg/unreg are called while guarded with the tracepoints_mutex */ static int sys_tracepoint_refcount; void syscall_regfunc(void) @@ -586,7 +594,6 @@ void syscall_regfunc(void) unsigned long flags; struct task_struct *g, *t; - mutex_lock(®func_mutex); if (!sys_tracepoint_refcount) { read_lock_irqsave(&tasklist_lock, flags); do_each_thread(g, t) { @@ -595,7 +602,6 @@ void syscall_regfunc(void) read_unlock_irqrestore(&tasklist_lock, flags); } sys_tracepoint_refcount++; - mutex_unlock(®func_mutex); } void syscall_unregfunc(void) @@ -603,7 +609,6 @@ void syscall_unregfunc(void) unsigned long flags; struct task_struct *g, *t; - mutex_lock(®func_mutex); sys_tracepoint_refcount--; if (!sys_tracepoint_refcount) { read_lock_irqsave(&tasklist_lock, flags); @@ -612,6 +617,5 @@ void syscall_unregfunc(void) } while_each_thread(g, t); read_unlock_irqrestore(&tasklist_lock, flags); } - mutex_unlock(®func_mutex); } #endif |