pstore: Shut down worker when unregistering

commit 6330d5534786d5315d56d558aa6d20740f97d80a upstream.

When built as a module and running with update_ms >= 0, pstore will Oops
during module unload since the work timer is still running. This makes sure
the worker is stopped before unloading.

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 9 insertions, 1 deletions

diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
index 14984d902a99..43033a3d66d5 100644
--- a/fs/pstore/platform.c
+++ b/fs/pstore/platform.c
@@ -704,6 +704,7 @@ int pstore_register(struct pstore_info *psi)
         if (psi->flags & PSTORE_FLAGS_PMSG)
                 pstore_register_pmsg();
 
+        /* Start watching for new records, if desired. */
         if (pstore_update_ms >= 0) {
                 pstore_timer.expires = jiffies +
                         msecs_to_jiffies(pstore_update_ms);
@@ -726,6 +727,11 @@ EXPORT_SYMBOL_GPL(pstore_register);
 
 void pstore_unregister(struct pstore_info *psi)
 {
+        /* Stop timer and make sure all work has finished. */
+        pstore_update_ms = -1;
+        del_timer_sync(&pstore_timer);
+        flush_work(&pstore_work);
+
         if (psi->flags & PSTORE_FLAGS_PMSG)
                 pstore_unregister_pmsg();
         if (psi->flags & PSTORE_FLAGS_FTRACE)
@@ -825,7 +831,9 @@ static void pstore_timefunc(unsigned long dummy)
                 schedule_work(&pstore_work);
         }
 
-        mod_timer(&pstore_timer, jiffies + msecs_to_jiffies(pstore_update_ms));
+        if (pstore_update_ms >= 0)
+                mod_timer(&pstore_timer,
+                          jiffies + msecs_to_jiffies(pstore_update_ms));
 }
 
 module_param(backend, charp, 0444);