releases/4.11.2/pstore-shut-down-worker-when-unregistering.patch

   1 From 6330d5534786d5315d56d558aa6d20740f97d80a Mon Sep 17 00:00:00 2001
   2 From: Kees Cook <keescook@chromium.org>
   3 Date: Mon, 6 Mar 2017 12:42:12 -0800
   4 Subject: pstore: Shut down worker when unregistering
   5
   6 From: Kees Cook <keescook@chromium.org>
   7
   8 commit 6330d5534786d5315d56d558aa6d20740f97d80a upstream.
   9
  10 When built as a module and running with update_ms >= 0, pstore will Oops
  11 during module unload since the work timer is still running. This makes sure
  12 the worker is stopped before unloading.
  13
  14 Signed-off-by: Kees Cook <keescook@chromium.org>
  15 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  16
  17 ---
  18  fs/pstore/platform.c |   10 +++++++++-
  19  1 file changed, 9 insertions(+), 1 deletion(-)
  20
  21 --- a/fs/pstore/platform.c
  22 +++ b/fs/pstore/platform.c
  23 @@ -709,6 +709,7 @@ int pstore_register(struct pstore_info *
  24         if (psi->flags & PSTORE_FLAGS_PMSG)
  25                 pstore_register_pmsg();
  26
  27 +       /* Start watching for new records, if desired. */
  28         if (pstore_update_ms >= 0) {
  29                 pstore_timer.expires = jiffies +
  30                         msecs_to_jiffies(pstore_update_ms);
  31 @@ -731,6 +732,11 @@ EXPORT_SYMBOL_GPL(pstore_register);
  32
  33  void pstore_unregister(struct pstore_info *psi)
  34  {
  35 +       /* Stop timer and make sure all work has finished. */
  36 +       pstore_update_ms = -1;
  37 +       del_timer_sync(&pstore_timer);
  38 +       flush_work(&pstore_work);
  39 +
  40         if (psi->flags & PSTORE_FLAGS_PMSG)
  41                 pstore_unregister_pmsg();
  42         if (psi->flags & PSTORE_FLAGS_FTRACE)
  43 @@ -830,7 +836,9 @@ static void pstore_timefunc(unsigned lon
  44                 schedule_work(&pstore_work);
  45         }
  46
  47 -       mod_timer(&pstore_timer, jiffies + msecs_to_jiffies(pstore_update_ms));
  48 +       if (pstore_update_ms >= 0)
  49 +               mod_timer(&pstore_timer,
  50 +                         jiffies + msecs_to_jiffies(pstore_update_ms));
  51  }
  52
  53  module_param(backend, charp, 0444);