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authorHugh Dickins <hughd@google.com>2012-08-21 16:15:45 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-08-21 16:45:02 -0700
commitf9aed62a2b12a8e04077737c9942111e14ed738e (patch)
treec6e4702415f153c615c961a7d6d5f35a718c34ef /mm
parent61e01be22e954f53a4bbac8066015d9f4ab9e42d (diff)
downloadlinux-linaro-stable-f9aed62a2b12a8e04077737c9942111e14ed738e.tar.gz
mm: change nr_ptes BUG_ON to WARN_ON
Occasionally an isolated BUG_ON(mm->nr_ptes) gets reported, indicating that not all the page tables allocated could be found and freed when exit_mmap() tore down the user address space. There's usually nothing we can say about it, beyond that it's probably a sign of some bad memory or memory corruption; though it might still indicate a bug in vma or page table management (and did recently reveal a race in THP, fixed a few months ago). But one overdue change we can make is from BUG_ON to WARN_ON. It's fairly likely that the system will crash shortly afterwards in some other way (for example, the BUG_ON(page_mapped(page)) in __delete_from_page_cache(), once an inode mapped into the lost page tables gets evicted); but might tell us more before that. Change the BUG_ON(page_mapped) to WARN_ON too? Later perhaps: I'm less eager, since that one has several times led to fixes. Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/mmap.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/mmap.c b/mm/mmap.c
index e3e86914f11a..9adee9fc0d8a 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2309,7 +2309,7 @@ void exit_mmap(struct mm_struct *mm)
}
vm_unacct_memory(nr_accounted);
- BUG_ON(mm->nr_ptes > (FIRST_USER_ADDRESS+PMD_SIZE-1)>>PMD_SHIFT);
+ WARN_ON(mm->nr_ptes > (FIRST_USER_ADDRESS+PMD_SIZE-1)>>PMD_SHIFT);
}
/* Insert vm structure into process list sorted by address