From: "Steven Rostedt (Google)" <[email protected]>
The subops filters use a "manager" ops to enable and disable its filters.
The manager ops can handle more than one subops, and its filter is what
controls what functions get set. Add a ftrace_hash_move_and_update_subops()
function that will update the manager ops when the subops filters change.
Signed-off-by: Steven Rostedt (Google) <[email protected]>
---
include/linux/ftrace.h | 3 ++
kernel/trace/ftrace.c | 96 ++++++++++++++++++++++++++++++++++++++----
2 files changed, 90 insertions(+), 9 deletions(-)
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 978a1d3b270a..63238a9a9270 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -227,6 +227,7 @@ ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops);
* ftrace_enabled.
* DIRECT - Used by the direct ftrace_ops helper for direct functions
* (internal ftrace only, should not be used by others)
+ * SUBOP - Is controlled by another op in field managed.
*/
enum {
FTRACE_OPS_FL_ENABLED = BIT(0),
@@ -247,6 +248,7 @@ enum {
FTRACE_OPS_FL_TRACE_ARRAY = BIT(15),
FTRACE_OPS_FL_PERMANENT = BIT(16),
FTRACE_OPS_FL_DIRECT = BIT(17),
+ FTRACE_OPS_FL_SUBOP = BIT(18),
};
#ifndef CONFIG_DYNAMIC_FTRACE_WITH_ARGS
@@ -336,6 +338,7 @@ struct ftrace_ops {
struct list_head list;
struct list_head subop_list;
ftrace_ops_func_t ops_func;
+ struct ftrace_ops *managed;
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
unsigned long direct_call;
#endif
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 38fb2a634b04..e447b04c0c9c 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -3424,7 +3424,8 @@ int ftrace_startup_subops(struct ftrace_ops *ops, struct ftrace_ops *subops, int
} else {
free_ftrace_hash(save_filter_hash);
free_ftrace_hash(save_notrace_hash);
- subops->flags |= FTRACE_OPS_FL_ENABLED;
+ subops->flags |= FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_SUBOP;
+ subops->managed = ops;
}
return ret;
}
@@ -3478,11 +3479,12 @@ int ftrace_startup_subops(struct ftrace_ops *ops, struct ftrace_ops *subops, int
ret = ftrace_update_ops(ops, filter_hash, notrace_hash);
free_ftrace_hash(filter_hash);
free_ftrace_hash(notrace_hash);
- if (ret < 0)
+ if (ret < 0) {
list_del(&subops->list);
- else
- subops->flags |= FTRACE_OPS_FL_ENABLED;
-
+ } else {
+ subops->flags |= FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_SUBOP;
+ subops->managed = ops;
+ }
return ret;
}
@@ -3527,6 +3529,8 @@ int ftrace_shutdown_subops(struct ftrace_ops *ops, struct ftrace_ops *subops, in
free_ftrace_hash(ops->func_hash->notrace_hash);
ops->func_hash->filter_hash = EMPTY_HASH;
ops->func_hash->notrace_hash = EMPTY_HASH;
+ subops->flags &= ~(FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_SUBOP);
+ subops->managed = NULL;
return 0;
}
@@ -3542,16 +3546,65 @@ int ftrace_shutdown_subops(struct ftrace_ops *ops, struct ftrace_ops *subops, in
}
ret = ftrace_update_ops(ops, filter_hash, notrace_hash);
- if (ret < 0)
+ if (ret < 0) {
list_add(&subops->list, &ops->subop_list);
- else
- subops->flags &= ~FTRACE_OPS_FL_ENABLED;
-
+ } else {
+ subops->flags &= ~(FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_SUBOP);
+ subops->managed = NULL;
+ }
free_ftrace_hash(filter_hash);
free_ftrace_hash(notrace_hash);
return ret;
}
+static int ftrace_hash_move_and_update_subops(struct ftrace_ops *subops,
+ struct ftrace_hash **orig_subhash,
+ struct ftrace_hash *hash,
+ int enable)
+{
+ struct ftrace_ops *ops = subops->managed;
+ struct ftrace_hash **orig_hash;
+ struct ftrace_hash *save_hash;
+ struct ftrace_hash *new_hash;
+ int ret;
+
+ /* Manager ops can not be subops (yet) */
+ if (WARN_ON_ONCE(!ops || ops->flags & FTRACE_OPS_FL_SUBOP))
+ return -EINVAL;
+
+ /* Move the new hash over to the subops hash */
+ save_hash = *orig_subhash;
+ *orig_subhash = __ftrace_hash_move(hash);
+ if (!*orig_subhash) {
+ *orig_subhash = save_hash;
+ return -ENOMEM;
+ }
+
+ /* Create a new_hash to hold the ops new functions */
+ if (enable) {
+ orig_hash = &ops->func_hash->filter_hash;
+ new_hash = append_hashes(ops);
+ } else {
+ orig_hash = &ops->func_hash->notrace_hash;
+ new_hash = intersect_hashes(ops);
+ }
+
+ /* Move the hash over to the new hash */
+ ret = ftrace_hash_move_and_update_ops(ops, orig_hash, new_hash, enable);
+
+ free_ftrace_hash(new_hash);
+
+ if (ret) {
+ /* Put back the original hash */
+ free_ftrace_hash_rcu(*orig_subhash);
+ *orig_subhash = save_hash;
+ } else {
+ free_ftrace_hash_rcu(save_hash);
+ }
+ return ret;
+}
+
+
static u64 ftrace_update_time;
unsigned long ftrace_update_tot_cnt;
unsigned long ftrace_number_of_pages;
@@ -4770,8 +4823,33 @@ static int ftrace_hash_move_and_update_ops(struct ftrace_ops *ops,
{
struct ftrace_ops_hash old_hash_ops;
struct ftrace_hash *old_hash;
+ struct ftrace_ops *op;
int ret;
+ if (ops->flags & FTRACE_OPS_FL_SUBOP)
+ return ftrace_hash_move_and_update_subops(ops, orig_hash, hash, enable);
+
+ /*
+ * If this ops is not enabled, it could be sharing its filters
+ * with a subop. If that's the case, update the subop instead of
+ * this ops. Shared filters are only allowed to have one ops set
+ * at a time, and if we update the ops that is not enabled,
+ * it will not affect subops that share it.
+ */
+ if (!(ops->flags & FTRACE_OPS_FL_ENABLED)) {
+ /* Check if any other manager subops maps to this hash */
+ do_for_each_ftrace_op(op, ftrace_ops_list) {
+ struct ftrace_ops *subops;
+
+ list_for_each_entry(subops, &op->subop_list, list) {
+ if ((subops->flags & FTRACE_OPS_FL_ENABLED) &&
+ subops->func_hash == ops->func_hash) {
+ return ftrace_hash_move_and_update_subops(subops, orig_hash, hash, enable);
+ }
+ }
+ } while_for_each_ftrace_op(op);
+ }
+
old_hash = *orig_hash;
old_hash_ops.filter_hash = ops->func_hash->filter_hash;
old_hash_ops.notrace_hash = ops->func_hash->notrace_hash;
--
2.43.0
On Sat, 01 Jun 2024 23:37:55 -0400
Steven Rostedt <[email protected]> wrote:
[...]
>
> +static int ftrace_hash_move_and_update_subops(struct ftrace_ops *subops,
> + struct ftrace_hash **orig_subhash,
> + struct ftrace_hash *hash,
> + int enable)
> +{
> + struct ftrace_ops *ops = subops->managed;
> + struct ftrace_hash **orig_hash;
> + struct ftrace_hash *save_hash;
> + struct ftrace_hash *new_hash;
> + int ret;
> +
> + /* Manager ops can not be subops (yet) */
> + if (WARN_ON_ONCE(!ops || ops->flags & FTRACE_OPS_FL_SUBOP))
> + return -EINVAL;
This does return if ops->flags & FTRACE_OPS_FL_SUBOP, but --> (1)
> +
> + /* Move the new hash over to the subops hash */
> + save_hash = *orig_subhash;
> + *orig_subhash = __ftrace_hash_move(hash);
> + if (!*orig_subhash) {
> + *orig_subhash = save_hash;
> + return -ENOMEM;
> + }
> +
> + /* Create a new_hash to hold the ops new functions */
> + if (enable) {
> + orig_hash = &ops->func_hash->filter_hash;
> + new_hash = append_hashes(ops);
> + } else {
> + orig_hash = &ops->func_hash->notrace_hash;
> + new_hash = intersect_hashes(ops);
> + }
> +
> + /* Move the hash over to the new hash */
> + ret = ftrace_hash_move_and_update_ops(ops, orig_hash, new_hash, enable);
This also a bit wired to me. maybe we need simple version like
`__ftrace_hash_move_and_update_ops()`
And call it from ftrace_hash_move_and_update_ops() and here?
> +
> + free_ftrace_hash(new_hash);
> +
> + if (ret) {
> + /* Put back the original hash */
> + free_ftrace_hash_rcu(*orig_subhash);
> + *orig_subhash = save_hash;
> + } else {
> + free_ftrace_hash_rcu(save_hash);
> + }
> + return ret;
> +}
> +
> +
> static u64 ftrace_update_time;
> unsigned long ftrace_update_tot_cnt;
> unsigned long ftrace_number_of_pages;
> @@ -4770,8 +4823,33 @@ static int ftrace_hash_move_and_update_ops(struct ftrace_ops *ops,
> {
> struct ftrace_ops_hash old_hash_ops;
> struct ftrace_hash *old_hash;
> + struct ftrace_ops *op;
> int ret;
>
> + if (ops->flags & FTRACE_OPS_FL_SUBOP)
> + return ftrace_hash_move_and_update_subops(ops, orig_hash, hash, enable);
(1) This calls ftrace_hash_move_and_update_subops() if ops->flags & FTRACE_OPS_FL_SUBOP ?
Thank you,
> +
> + /*
> + * If this ops is not enabled, it could be sharing its filters
> + * with a subop. If that's the case, update the subop instead of
> + * this ops. Shared filters are only allowed to have one ops set
> + * at a time, and if we update the ops that is not enabled,
> + * it will not affect subops that share it.
> + */
> + if (!(ops->flags & FTRACE_OPS_FL_ENABLED)) {
> + /* Check if any other manager subops maps to this hash */
> + do_for_each_ftrace_op(op, ftrace_ops_list) {
> + struct ftrace_ops *subops;
> +
> + list_for_each_entry(subops, &op->subop_list, list) {
> + if ((subops->flags & FTRACE_OPS_FL_ENABLED) &&
> + subops->func_hash == ops->func_hash) {
> + return ftrace_hash_move_and_update_subops(subops, orig_hash, hash, enable);
> + }
> + }
> + } while_for_each_ftrace_op(op);
> + }
> +
> old_hash = *orig_hash;
> old_hash_ops.filter_hash = ops->func_hash->filter_hash;
> old_hash_ops.notrace_hash = ops->func_hash->notrace_hash;
> --
> 2.43.0
>
>
--
Masami Hiramatsu (Google) <[email protected]>
On Mon, 3 Jun 2024 11:37:23 +0900
Masami Hiramatsu (Google) <[email protected]> wrote:
> On Sat, 01 Jun 2024 23:37:55 -0400
> Steven Rostedt <[email protected]> wrote:
>
> [...]
> >
> > +static int ftrace_hash_move_and_update_subops(struct ftrace_ops *subops,
> > + struct ftrace_hash **orig_subhash,
> > + struct ftrace_hash *hash,
> > + int enable)
> > +{
> > + struct ftrace_ops *ops = subops->managed;
> > + struct ftrace_hash **orig_hash;
> > + struct ftrace_hash *save_hash;
> > + struct ftrace_hash *new_hash;
> > + int ret;
> > +
> > + /* Manager ops can not be subops (yet) */
> > + if (WARN_ON_ONCE(!ops || ops->flags & FTRACE_OPS_FL_SUBOP))
> > + return -EINVAL;
>
> This does return if ops->flags & FTRACE_OPS_FL_SUBOP, but --> (1)
Yes, because what is passed in is "subops" and "ops" is subops->managed.
>
> > +
> > + /* Move the new hash over to the subops hash */
> > + save_hash = *orig_subhash;
> > + *orig_subhash = __ftrace_hash_move(hash);
> > + if (!*orig_subhash) {
> > + *orig_subhash = save_hash;
> > + return -ENOMEM;
> > + }
> > +
> > + /* Create a new_hash to hold the ops new functions */
> > + if (enable) {
> > + orig_hash = &ops->func_hash->filter_hash;
> > + new_hash = append_hashes(ops);
> > + } else {
> > + orig_hash = &ops->func_hash->notrace_hash;
> > + new_hash = intersect_hashes(ops);
> > + }
> > +
> > + /* Move the hash over to the new hash */
> > + ret = ftrace_hash_move_and_update_ops(ops, orig_hash, new_hash, enable);
>
> This also a bit wired to me. maybe we need simple version like
>
> `__ftrace_hash_move_and_update_ops()`
>
> And call it from ftrace_hash_move_and_update_ops() and here?
We could do that. I almost did due to other issues but I reworked the code
where I didn't need to.
>
> > +
> > + free_ftrace_hash(new_hash);
> > +
> > + if (ret) {
> > + /* Put back the original hash */
> > + free_ftrace_hash_rcu(*orig_subhash);
> > + *orig_subhash = save_hash;
> > + } else {
> > + free_ftrace_hash_rcu(save_hash);
> > + }
> > + return ret;
> > +}
> > +
> > +
> > static u64 ftrace_update_time;
> > unsigned long ftrace_update_tot_cnt;
> > unsigned long ftrace_number_of_pages;
> > @@ -4770,8 +4823,33 @@ static int ftrace_hash_move_and_update_ops(struct ftrace_ops *ops,
> > {
> > struct ftrace_ops_hash old_hash_ops;
> > struct ftrace_hash *old_hash;
> > + struct ftrace_ops *op;
> > int ret;
> >
> > + if (ops->flags & FTRACE_OPS_FL_SUBOP)
> > + return ftrace_hash_move_and_update_subops(ops, orig_hash, hash, enable);
>
> (1) This calls ftrace_hash_move_and_update_subops() if ops->flags & FTRACE_OPS_FL_SUBOP ?
Yes, because ops turns into subops, and the ops above it is its manager ops.
-- Steve
On Mon, 3 Jun 2024 10:52:50 -0400
Steven Rostedt <[email protected]> wrote:
> On Mon, 3 Jun 2024 11:37:23 +0900
> Masami Hiramatsu (Google) <[email protected]> wrote:
>
> > On Sat, 01 Jun 2024 23:37:55 -0400
> > Steven Rostedt <[email protected]> wrote:
> >
> > [...]
> > >
> > > +static int ftrace_hash_move_and_update_subops(struct ftrace_ops *subops,
> > > + struct ftrace_hash **orig_subhash,
> > > + struct ftrace_hash *hash,
> > > + int enable)
> > > +{
> > > + struct ftrace_ops *ops = subops->managed;
> > > + struct ftrace_hash **orig_hash;
> > > + struct ftrace_hash *save_hash;
> > > + struct ftrace_hash *new_hash;
> > > + int ret;
> > > +
> > > + /* Manager ops can not be subops (yet) */
> > > + if (WARN_ON_ONCE(!ops || ops->flags & FTRACE_OPS_FL_SUBOP))
> > > + return -EINVAL;
> >
> > This does return if ops->flags & FTRACE_OPS_FL_SUBOP, but --> (1)
>
> Yes, because what is passed in is "subops" and "ops" is subops->managed.
Ah, I missed that point. OK, I got it.
>
> >
> > > +
> > > + /* Move the new hash over to the subops hash */
> > > + save_hash = *orig_subhash;
> > > + *orig_subhash = __ftrace_hash_move(hash);
> > > + if (!*orig_subhash) {
> > > + *orig_subhash = save_hash;
> > > + return -ENOMEM;
> > > + }
> > > +
> > > + /* Create a new_hash to hold the ops new functions */
> > > + if (enable) {
> > > + orig_hash = &ops->func_hash->filter_hash;
> > > + new_hash = append_hashes(ops);
> > > + } else {
> > > + orig_hash = &ops->func_hash->notrace_hash;
> > > + new_hash = intersect_hashes(ops);
> > > + }
> > > +
> > > + /* Move the hash over to the new hash */
> > > + ret = ftrace_hash_move_and_update_ops(ops, orig_hash, new_hash, enable);
So this `ops` is managed ops of this subops.
> >
> > This also a bit wired to me. maybe we need simple version like
> >
> > `__ftrace_hash_move_and_update_ops()`
> >
> > And call it from ftrace_hash_move_and_update_ops() and here?
>
> We could do that. I almost did due to other issues but I reworked the code
> where I didn't need to.
>
> >
> > > +
> > > + free_ftrace_hash(new_hash);
> > > +
> > > + if (ret) {
> > > + /* Put back the original hash */
> > > + free_ftrace_hash_rcu(*orig_subhash);
> > > + *orig_subhash = save_hash;
> > > + } else {
> > > + free_ftrace_hash_rcu(save_hash);
> > > + }
> > > + return ret;
> > > +}
> > > +
> > > +
> > > static u64 ftrace_update_time;
> > > unsigned long ftrace_update_tot_cnt;
> > > unsigned long ftrace_number_of_pages;
> > > @@ -4770,8 +4823,33 @@ static int ftrace_hash_move_and_update_ops(struct ftrace_ops *ops,
> > > {
> > > struct ftrace_ops_hash old_hash_ops;
> > > struct ftrace_hash *old_hash;
> > > + struct ftrace_ops *op;
> > > int ret;
> > >
> > > + if (ops->flags & FTRACE_OPS_FL_SUBOP)
> > > + return ftrace_hash_move_and_update_subops(ops, orig_hash, hash, enable);
> >
> > (1) This calls ftrace_hash_move_and_update_subops() if ops->flags & FTRACE_OPS_FL_SUBOP ?
>
> Yes, because ops turns into subops, and the ops above it is its manager ops.
Ah, OK. This `ops` is a subops.
Thank you,
>
> -- Steve
>
--
Masami Hiramatsu (Google) <[email protected]>