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FAILED: patch "[PATCH] driver core: Fix locking bug in" failed to apply to 5.4-stable tree

PATCH [email protected] 1 participant 1 message Apr 11, 2021

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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 <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From eed6e41813deb9ee622cd9242341f21430d7789f Mon Sep 17 00:00:00 2001
From: Saravana Kannan <[email protected]>
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 [email protected]
Fixes 25b4e70dcce9 ("driver core: allow stopping deferred probe after init")
Signed-off-by Saravana Kannan <[email protected]>
Link https://lore.kernel.org/r/[email protected] open here
Signed-off-by Greg Kroah-Hartman <[email protected]>
drivers/base/dd.c +5 -3
index e2cf3b29123e..37a5e5f8b221 100644
@@ -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);