queue-4.19/arm-8840-1-use-a-raw_spinlock_t-in-unwind.patch

   1 From aba9b9930c12418dad8f189386f0f89a14633408 Mon Sep 17 00:00:00 2001
   2 From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
   3 Date: Wed, 13 Feb 2019 17:14:42 +0100
   4 Subject: ARM: 8840/1: use a raw_spinlock_t in unwind
   5
   6 [ Upstream commit 74ffe79ae538283bbf7c155e62339f1e5c87b55a ]
   7
   8 Mostly unwind is done with irqs enabled however SLUB may call it with
   9 irqs disabled while creating a new SLUB cache.
  10
  11 I had system freeze while loading a module which called
  12 kmem_cache_create() on init. That means SLUB's __slab_alloc() disabled
  13 interrupts and then
  14
  15 ->new_slab_objects()
  16  ->new_slab()
  17   ->setup_object()
  18    ->setup_object_debug()
  19     ->init_tracking()
  20      ->set_track()
  21       ->save_stack_trace()
  22        ->save_stack_trace_tsk()
  23         ->walk_stackframe()
  24          ->unwind_frame()
  25           ->unwind_find_idx()
  26            =>spin_lock_irqsave(&unwind_lock);
  27
  28 Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
  29 Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
  30 Signed-off-by: Sasha Levin <sashal@kernel.org>
  31 ---
  32  arch/arm/kernel/unwind.c | 14 +++++++-------
  33  1 file changed, 7 insertions(+), 7 deletions(-)
  34
  35 diff --git a/arch/arm/kernel/unwind.c b/arch/arm/kernel/unwind.c
  36 index 0bee233fef9a..314cfb232a63 100644
  37 --- a/arch/arm/kernel/unwind.c
  38 +++ b/arch/arm/kernel/unwind.c
  39 @@ -93,7 +93,7 @@ extern const struct unwind_idx __start_unwind_idx[];
  40  static const struct unwind_idx *__origin_unwind_idx;
  41  extern const struct unwind_idx __stop_unwind_idx[];
  42
  43 -static DEFINE_SPINLOCK(unwind_lock);
  44 +static DEFINE_RAW_SPINLOCK(unwind_lock);
  45  static LIST_HEAD(unwind_tables);
  46
  47  /* Convert a prel31 symbol to an absolute address */
  48 @@ -201,7 +201,7 @@ static const struct unwind_idx *unwind_find_idx(unsigned long addr)
  49                 /* module unwind tables */
  50                 struct unwind_table *table;
  51
  52 -               spin_lock_irqsave(&unwind_lock, flags);
  53 +               raw_spin_lock_irqsave(&unwind_lock, flags);
  54                 list_for_each_entry(table, &unwind_tables, list) {
  55                         if (addr >= table->begin_addr &&
  56                             addr < table->end_addr) {
  57 @@ -213,7 +213,7 @@ static const struct unwind_idx *unwind_find_idx(unsigned long addr)
  58                                 break;
  59                         }
  60                 }
  61 -               spin_unlock_irqrestore(&unwind_lock, flags);
  62 +               raw_spin_unlock_irqrestore(&unwind_lock, flags);
  63         }
  64
  65         pr_debug("%s: idx = %p\n", __func__, idx);
  66 @@ -529,9 +529,9 @@ struct unwind_table *unwind_table_add(unsigned long start, unsigned long size,
  67         tab->begin_addr = text_addr;
  68         tab->end_addr = text_addr + text_size;
  69
  70 -       spin_lock_irqsave(&unwind_lock, flags);
  71 +       raw_spin_lock_irqsave(&unwind_lock, flags);
  72         list_add_tail(&tab->list, &unwind_tables);
  73 -       spin_unlock_irqrestore(&unwind_lock, flags);
  74 +       raw_spin_unlock_irqrestore(&unwind_lock, flags);
  75
  76         return tab;
  77  }
  78 @@ -543,9 +543,9 @@ void unwind_table_del(struct unwind_table *tab)
  79         if (!tab)
  80                 return;
  81
  82 -       spin_lock_irqsave(&unwind_lock, flags);
  83 +       raw_spin_lock_irqsave(&unwind_lock, flags);
  84         list_del(&tab->list);
  85 -       spin_unlock_irqrestore(&unwind_lock, flags);
  86 +       raw_spin_unlock_irqrestore(&unwind_lock, flags);
  87
  88         kfree(tab);
  89  }
  90 --
  91 2.19.1
  92