diff options
| author | Rafael J. Wysocki <rjw@sisk.pl> | 2011-07-06 20:15:23 +0200 |
|---|---|---|
| committer | Paul Gortmaker <paul.gortmaker@windriver.com> | 2012-05-17 11:21:04 -0400 |
| commit | 17faeb6e7db6c98e235ec085c4157340e6aa5d4e (patch) | |
| tree | 6bdd0f5bf21ce3f5b98c92c664bc69c0f4a594c8 /kernel | |
| parent | 561c6e2d14e0ac50eb1716b94fb297177d824478 (diff) | |
PM / Hibernate: Fix free_unnecessary_pages()
commit 4d4cf23cdde2f8f9324f5684a7f349e182039529 upstream.
There is a bug in free_unnecessary_pages() that causes it to
attempt to free too many pages in some cases, which triggers the
BUG_ON() in memory_bm_clear_bit() for copy_bm. Namely, if
count_data_pages() is initially greater than alloc_normal, we get
to_free_normal equal to 0 and "save" greater from 0. In that case,
if the sum of "save" and count_highmem_pages() is greater than
alloc_highmem, we subtract a positive number from to_free_normal.
Hence, since to_free_normal was 0 before the subtraction and is
an unsigned int, the result is converted to a huge positive number
that is used as the number of pages to free.
Fix this bug by checking if to_free_normal is actually greater
than or equal to the number we're going to subtract from it.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Reported-and-tested-by: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/power/snapshot.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c index a20446726556..5e16efe0ae69 100644 --- a/kernel/power/snapshot.c +++ b/kernel/power/snapshot.c @@ -1194,7 +1194,11 @@ static void free_unnecessary_pages(void) to_free_highmem = alloc_highmem - save; } else { to_free_highmem = 0; - to_free_normal -= save - alloc_highmem; + save -= alloc_highmem; + if (to_free_normal > save) + to_free_normal -= save; + else + to_free_normal = 0; } memory_bm_position_reset(©_bm); |