Commit 452b94b8 authored Mar 19, 2017 by Linus Torvalds

mm/swap: don't BUG_ON() due to uninitialized swap slot cache



This BUG_ON() triggered for me once at shutdown, and I don't see a
reason for the check.  The code correctly checks whether the swap slot
cache is usable or not, so an uninitialized swap slot cache is not
actually problematic afaik.

I've temporarily just switched the BUG_ON() to a WARN_ON_ONCE(), since
I'm not sure why that seemingly pointless check was there.  I suspect
the real fix is to just remove it entirely, but for now we'll warn about
it but not bring the machine down.

Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent a07a6e41

mm/swap_slots.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -267,7 +267,7 @@ int free_swap_slot(swp_entry_t entry)
		{
		struct swap_slots_cache *cache;

		BUG_ON(!swap_slot_cache_initialized);
		WARN_ON_ONCE(!swap_slot_cache_initialized);

		cache = &get_cpu_var(swp_slots);
		if (use_swap_slot_cache && cache->slots_ret) {

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