Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 4.19 11/13] driver core: Fix locking bug in deferred_probe_timeout_work_func() | Date | Thu, 15 Apr 2021 16:48:00 +0200 |
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From: Saravana Kannan <saravanak@google.com>
commit eed6e41813deb9ee622cd9242341f21430d7789f upstream.
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> Link: https://lore.kernel.org/r/20210402040342.2944858-2-saravanak@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/base/dd.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)
--- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -254,14 +254,16 @@ int driver_deferred_probe_check_state(st static void deferred_probe_timeout_work_func(struct work_struct *work) { - struct device_private *private, *p; + struct device_private *p; 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"); + 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); } static DECLARE_DELAYED_WORK(deferred_probe_timeout_work, deferred_probe_timeout_work_func);
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