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authorLinus Torvalds <torvalds@linux-foundation.org>2016-10-03 21:03:48 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-10-28 03:01:34 -0400
commite765b192093d3b7fc8899bd33b0867492a405ba0 (patch)
tree2a9fec0e1f91935f5a5ed3303764a9df490feedc
parentddafc880082e0e7b809ca84866eeddb2b5ef118e (diff)
Using BUG_ON() as an assert() is _never_ acceptable
commit 21f54ddae449f4bdd9f1498124901d67202243d9 upstream. 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 <hannes@cmpxchg.org> Cc: Miklos Szeredi <miklos@szeredi.hu> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--include/linux/swap.h4
1 files changed, 2 insertions, 2 deletions
diff --git a/include/linux/swap.h b/include/linux/swap.h
index b28de19aadbf..d8ca2eaa3a8b 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -266,7 +266,7 @@ 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--;
}
@@ -282,7 +282,7 @@ 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;
}