tree ae03b0cb87975221eca536952c44764d17b1c6ed
parent e6445f52d9c8b0e6557a45fa7d0e8e088d430a8c
author Linus Torvalds <torvalds@linux-foundation.org> 1475553828 -0700
committer Linus Torvalds <torvalds@linux-foundation.org> 1475553828 -0700

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 <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>