[PATCH] ref_tracker: do xarray and workqueue job initializations earlier

[PATCH] ref_tracker: do xarray and workqueue job initializations earlier

[Jeff Layton]

The kernel test robot reported an oops that occurred when attempting to
deregister a dentry from the xarray during subsys_initcall().

The ref_tracker xarrays and workqueue job are being initialized in
late_initcall() which is too late. Move those to postcore_initcall()
instead.

Fixes: 65b584f53611 ("ref_tracker: automatically register a file in debugfs for a ref_tracker_dir")
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202506251406.c28f2adb-lkp@intel.com
Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
 lib/ref_tracker.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/lib/ref_tracker.c b/lib/ref_tracker.c
index dcf923a1edf5b7d7342bf61ccec5b54a2eceab5b..a9e6ffcff04b1da162a5a6add6bff075c2c9405e 100644
--- a/lib/ref_tracker.c
+++ b/lib/ref_tracker.c
@@ -516,13 +516,19 @@ static void debugfs_reap_work(struct work_struct *work)
 	} while (reaped);
 }
 
-static int __init ref_tracker_debugfs_init(void)
+static int __init ref_tracker_debugfs_postcore_init(void)
 {
 	INIT_WORK(&debugfs_reap_worker, debugfs_reap_work);
 	xa_init_flags(&debugfs_dentries, XA_FLAGS_LOCK_IRQ);
 	xa_init_flags(&debugfs_symlinks, XA_FLAGS_LOCK_IRQ);
+	return 0;
+}
+postcore_initcall(ref_tracker_debugfs_postcore_init);
+
+static int __init ref_tracker_debugfs_late_init(void)
+{
 	ref_tracker_debug_dir = debugfs_create_dir("ref_tracker", NULL);
 	return 0;
 }
-late_initcall(ref_tracker_debugfs_init);
+late_initcall(ref_tracker_debugfs_late_init);
 #endif /* CONFIG_DEBUG_FS */

---
base-commit: a9b24b3583ae1da7dbda031f141264f2da260219
change-id: 20250626-reftrack-dbgfs-ed396c24853e

Best regards,
-- 
Jeff Layton <jlayton@kernel.org>

Re: [PATCH] ref_tracker: do xarray and workqueue job initializations earlier

[Jakub Kicinski]

On Thu, 26 Jun 2025 08:52:14 -0400 Jeff Layton wrote:
> The kernel test robot reported an oops that occurred when attempting to
> deregister a dentry from the xarray during subsys_initcall().
> 
> The ref_tracker xarrays and workqueue job are being initialized in
> late_initcall() which is too late. Move those to postcore_initcall()
> instead.

Applied to net-next (on top of an -rc tag again, if anyone else
needs it). Thanks!