ftrace: Synchronize the initialization of ftrace_opsgrafted

There's some internal state that ftrace_ops needs to have set, but since
it can be declared outside of the ftrace.c code, it calls
ftrace_ops_init() on the ops in every global function. The issue is that
if two tasks call it on the same ops at the same time it is possible to
have the initialization of one corrupt the initialization of the other
call.

Create a ops_mutex to use to synchronize every initialization of the
ftrace_ops. The mutex is taken within checking the ftrace_ops flag that
states it was initializied but the flag is checked again after the mutex
has been taken. Checking first outside the mutex allows it to shortcut
having to take the mutex. But then the check needs to be done again after
the mute is taken in case of races.

Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home
Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock")
Reported-by: sashiko-bot@kernel.org
Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 78 insertions, 0 deletions

diff --git a/rust/helpers/drm.c b/rust/helpers/drm.c
new file mode 100644
index 000000000..65f3f22b0
--- /dev/null
+++ b/rust/helpers/drm.c
@@ -0,0 +1,78 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <drm/drm_gem.h>
+#include <drm/drm_gem_shmem_helper.h>
+#include <drm/drm_vma_manager.h>
+
+#ifdef CONFIG_DRM
+
+__rust_helper void rust_helper_drm_gem_object_get(struct drm_gem_object *obj)
+{
+	drm_gem_object_get(obj);
+}
+
+__rust_helper void rust_helper_drm_gem_object_put(struct drm_gem_object *obj)
+{
+	drm_gem_object_put(obj);
+}
+
+__rust_helper __u64
+rust_helper_drm_vma_node_offset_addr(struct drm_vma_offset_node *node)
+{
+	return drm_vma_node_offset_addr(node);
+}
+
+#ifdef CONFIG_DRM_GEM_SHMEM_HELPER
+__rust_helper void
+rust_helper_drm_gem_shmem_object_free(struct drm_gem_object *obj)
+{
+	return drm_gem_shmem_object_free(obj);
+}
+
+__rust_helper void
+rust_helper_drm_gem_shmem_object_print_info(struct drm_printer *p, unsigned int indent,
+					    const struct drm_gem_object *obj)
+{
+	drm_gem_shmem_object_print_info(p, indent, obj);
+}
+
+__rust_helper int
+rust_helper_drm_gem_shmem_object_pin(struct drm_gem_object *obj)
+{
+	return drm_gem_shmem_object_pin(obj);
+}
+
+__rust_helper void
+rust_helper_drm_gem_shmem_object_unpin(struct drm_gem_object *obj)
+{
+	drm_gem_shmem_object_unpin(obj);
+}
+
+__rust_helper struct sg_table *
+rust_helper_drm_gem_shmem_object_get_sg_table(struct drm_gem_object *obj)
+{
+	return drm_gem_shmem_object_get_sg_table(obj);
+}
+
+__rust_helper int
+rust_helper_drm_gem_shmem_object_vmap(struct drm_gem_object *obj,
+				      struct iosys_map *map)
+{
+	return drm_gem_shmem_object_vmap(obj, map);
+}
+
+__rust_helper void
+rust_helper_drm_gem_shmem_object_vunmap(struct drm_gem_object *obj,
+					struct iosys_map *map)
+{
+	drm_gem_shmem_object_vunmap(obj, map);
+}
+
+__rust_helper int
+rust_helper_drm_gem_shmem_object_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma)
+{
+	return drm_gem_shmem_object_mmap(obj, vma);
+}
+
+#endif /* CONFIG_DRM_GEM_SHMEM_HELPER */
+#endif /* CONFIG_DRM */