From 21f54ddae449f4bdd9f1498124901d67202243d9 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Mon, 3 Oct 2016 21:03:48 -0700 Subject: [PATCH] Using BUG_ON() as an assert() is _never_ acceptable That just generally kills the machine, and makes debugging only much harder, since the traces may long be gone. Debugging by assert() is a disease. Don't do it. If you can continue, you're much better off doing so with a live machine where you have a much higher chance that the report actually makes it to the system logs, rather than result in a machine that is just completely dead. The only valid situation for BUG_ON() is when continuing is not an option, because there is massive corruption. But if you are just verifying that something is true, you warn about your broken assumptions (preferably just once), and limp on. Fixes: 22f2ac51b6d6 ("mm: workingset: fix crash in shadow node shrinker caused by replace_page_cache_page()") Cc: Johannes Weiner Cc: Miklos Szeredi Cc: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/swap.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/include/linux/swap.h b/include/linux/swap.h index 4a529c984a3f..e1d761463243 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -257,7 +257,7 @@ static inline void workingset_node_pages_inc(struct radix_tree_node *node) static inline void workingset_node_pages_dec(struct radix_tree_node *node) { - VM_BUG_ON(!workingset_node_pages(node)); + VM_WARN_ON_ONCE(!workingset_node_pages(node)); node->count--; } @@ -273,7 +273,7 @@ static inline void workingset_node_shadows_inc(struct radix_tree_node *node) static inline void workingset_node_shadows_dec(struct radix_tree_node *node) { - VM_BUG_ON(!workingset_node_shadows(node)); + VM_WARN_ON_ONCE(!workingset_node_shadows(node)); node->count -= 1U << RADIX_TREE_COUNT_SHIFT; } -- 2.20.1