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| author | Hugh Dickins <hughd@google.com> | 2012-08-21 16:15:45 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-08-21 16:45:02 -0700 |
| commit | f9aed62a2b12a8e04077737c9942111e14ed738e (patch) | |
| tree | c6e4702415f153c615c961a7d6d5f35a718c34ef | |
| parent | 61e01be22e954f53a4bbac8066015d9f4ab9e42d (diff) | |
| download | linux-f9aed62a2b12a8e04077737c9942111e14ed738e.tar.bz2 | |
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>
| -rw-r--r-- | mm/mmap.c | 2 |
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 |