breeze/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-01-25 15:03:52 +08:00
Code Issues Packages Projects Releases Wiki Activity

fgraph: Keep track of when fgraph_ops are registered or not

Browse Source 
Add a warning if unregister_ftrace_graph() is called without ever
registering it, or if register_ftrace_graph() is called twice. This can
detect errors when they happen and not later when there's a side effect:

Link: https://lore.kernel.org/all/20250617120830.24fbdd62@gandalf.local.home/

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/20250701194451.22e34724@gandalf.local.home
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
This commit is contained in:
Steven Rostedt
2025-07-01 19:44:51 -04:00
committed by Steven Rostedt (Google)
parent 437889b926
commit 218d372ce8
1 changed files with 13 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files

16
kernel/trace/fgraph.c
View File

@@ -1325,6 +1325,10 @@ int register_ftrace_graph(struct fgraph_ops *gops)
int ret = 0;
int i = -1;
if (WARN_ONCE(gops->ops.flags & FTRACE_OPS_FL_GRAPH,
"function graph ops registered again"))
return -EBUSY;
guard(mutex)(&ftrace_lock);
if (!fgraph_stack_cachep) {
@@ -1401,17 +1405,21 @@ void unregister_ftrace_graph(struct fgraph_ops *gops)
{
int command = 0;
if (WARN_ONCE(!(gops->ops.flags & FTRACE_OPS_FL_GRAPH),
"function graph ops unregistered without registering"))
return;
guard(mutex)(&ftrace_lock);
if (unlikely(!ftrace_graph_active))
return;
goto out;
if (unlikely(gops->idx < 0 || gops->idx >= FGRAPH_ARRAY_SIZE ||
fgraph_array[gops->idx] != gops))
return;
goto out;
if (fgraph_lru_release_index(gops->idx) < 0)
return;
goto out;
fgraph_array[gops->idx] = &fgraph_stub;
@@ -1434,4 +1442,6 @@ void unregister_ftrace_graph(struct fgraph_ops *gops)
unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
}
gops->saved_func = NULL;
out:
gops->ops.flags &= ~FTRACE_OPS_FL_GRAPH;
}