The patch below does not apply to the 5.4-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@xxxxxxxxxxxxxxx>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From eed6e41813deb9ee622cd9242341f21430d7789f Mon Sep 17 00:00:00 2001
From: Saravana Kannan <saravanak@xxxxxxxxxx>
Date: Thu, 1 Apr 2021 21:03:40 -0700
Subject: [PATCH] driver core: Fix locking bug in
deferred_probe_timeout_work_func()
list_for_each_entry_safe() is only useful if we are deleting nodes in a
linked list within the loop. It doesn't protect against other threads
adding/deleting nodes to the list in parallel. We need to grab
deferred_probe_mutex when traversing the deferred_probe_pending_list.
Cc: stable@xxxxxxxxxxxxxxx
Fixes: 25b4e70dcce9 ("driver core: allow stopping deferred probe after init")
Signed-off-by: Saravana Kannan <saravanak@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20210402040342.2944858-2-saravanak@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
diff --git a/drivers/base/dd.c b/drivers/base/dd.c
index e2cf3b29123e..37a5e5f8b221 100644
--- a/drivers/base/dd.c
+++ b/drivers/base/dd.c
@@ -292,14 +292,16 @@ int driver_deferred_probe_check_state(struct device *dev)
static void deferred_probe_timeout_work_func(struct work_struct *work)
{
- struct device_private *private, *p;
+ struct device_private *p;
driver_deferred_probe_timeout = 0;
driver_deferred_probe_trigger();
flush_work(&deferred_probe_work);
- list_for_each_entry_safe(private, p, &deferred_probe_pending_list, deferred_probe)
- dev_info(private->device, "deferred probe pending\n");
+ mutex_lock(&deferred_probe_mutex);
+ list_for_each_entry(p, &deferred_probe_pending_list, deferred_probe)
+ dev_info(p->device, "deferred probe pending\n");
+ mutex_unlock(&deferred_probe_mutex);
wake_up_all(&probe_timeout_waitqueue);
}
static DECLARE_DELAYED_WORK(deferred_probe_timeout_work, deferred_probe_timeout_work_func);
