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ARM: 8840/1: use a raw_spinlock_t in unwind 

Mostly unwind is done with irqs enabled however SLUB may call it with
irqs disabled while creating a new SLUB cache.

I had system freeze while loading a module which called
kmem_cache_create() on init. That means SLUB's __slab_alloc() disabled
interrupts and then

->new_slab_objects()
 ->new_slab()
  ->setup_object()
   ->setup_object_debug()
    ->init_tracking()
     ->set_track()
      ->save_stack_trace()
       ->save_stack_trace_tsk()
        ->walk_stackframe()
         ->unwind_frame()
          ->unwind_find_idx()
           =>spin_lock_irqsave(&unwind_lock);

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
This commit is contained in:
Sebastian Andrzej Siewior 2019-02-13 17:14:42 +01:00 committed by Russell King
parent 143c2a89e0
commit 74ffe79ae5
1 changed files with 7 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
arch/arm/kernel/unwind.c
View File

@ -93,7 +93,7 @@ extern const struct unwind_idx __start_unwind_idx[];
static const struct unwind_idx *__origin_unwind_idx;
extern const struct unwind_idx __stop_unwind_idx[];
static DEFINE_SPINLOCK(unwind_lock);
static DEFINE_RAW_SPINLOCK(unwind_lock);
static LIST_HEAD(unwind_tables);
/* Convert a prel31 symbol to an absolute address */
@ -201,7 +201,7 @@ static const struct unwind_idx *unwind_find_idx(unsigned long addr)
/* module unwind tables */
struct unwind_table *table;
spin_lock_irqsave(&unwind_lock, flags);
raw_spin_lock_irqsave(&unwind_lock, flags);
list_for_each_entry(table, &unwind_tables, list) {
if (addr >= table->begin_addr &&
addr < table->end_addr) {
@ -213,7 +213,7 @@ static const struct unwind_idx *unwind_find_idx(unsigned long addr)
break;
}
}
spin_unlock_irqrestore(&unwind_lock, flags);
raw_spin_unlock_irqrestore(&unwind_lock, flags);
}
pr_debug("%s: idx = %p\n", __func__, idx);
@ -529,9 +529,9 @@ struct unwind_table *unwind_table_add(unsigned long start, unsigned long size,
tab->begin_addr = text_addr;
tab->end_addr = text_addr + text_size;
spin_lock_irqsave(&unwind_lock, flags);
raw_spin_lock_irqsave(&unwind_lock, flags);
list_add_tail(&tab->list, &unwind_tables);
spin_unlock_irqrestore(&unwind_lock, flags);
raw_spin_unlock_irqrestore(&unwind_lock, flags);
return tab;
}
@ -543,9 +543,9 @@ void unwind_table_del(struct unwind_table *tab)
if (!tab)
return;
spin_lock_irqsave(&unwind_lock, flags);
raw_spin_lock_irqsave(&unwind_lock, flags);
list_del(&tab->list);
spin_unlock_irqrestore(&unwind_lock, flags);
raw_spin_unlock_irqrestore(&unwind_lock, flags);
kfree(tab);
}