From: Saravana Kannan <saravanak@google.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"Rafael J. Wysocki" <rafael@kernel.org>,
Rob Herring <robh@kernel.org>
Cc: Saravana Kannan <saravanak@google.com>,
kernel-team@android.com, linux-kernel@vger.kernel.org,
stable@vger.kernel.org
Subject: [PATCH v1 1/2] driver core: Fix locking bug in deferred_probe_timeout_work_func()
Date: Thu, 1 Apr 2021 21:03:40 -0700 [thread overview]
Message-ID: <20210402040342.2944858-2-saravanak@google.com> (raw)
In-Reply-To: <20210402040342.2944858-1-saravanak@google.com>
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@vger.kernel.org
Fixes: 25b4e70dcce9 ("driver core: allow stopping deferred probe after init")
Signed-off-by: Saravana Kannan <saravanak@google.com>
---
drivers/base/dd.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/drivers/base/dd.c b/drivers/base/dd.c
index 20b69b5e0e91..28ad8afd87bc 100644
--- a/drivers/base/dd.c
+++ b/drivers/base/dd.c
@@ -291,14 +291,16 @@ 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);
--
2.31.0.208.g409f899ff0-goog
next prev parent reply other threads:[~2021-04-02 4:04 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-02 4:03 [PATCH v1 0/2] Fix deferred_probe_timeout and fw_devlink=on Saravana Kannan
2021-04-02 4:03 ` Saravana Kannan [this message]
2021-04-02 4:03 ` [PATCH v1 2/2] driver core: Improve fw_devlink & deferred_probe_timeout interaction Saravana Kannan
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