diff options
| author | Rafael J. Wysocki <rjw@sisk.pl> | 2011-07-06 20:15:23 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2011-07-13 05:31:26 +0200 |
| commit | 386f12d6c880e3c7b9a31da1c7b5cca3500470d0 (patch) | |
| tree | ecb51c87490f35b9fb9541515fae3a9e37fd8e18 /kernel | |
| parent | 87f97028802669d593a5f8b99249d47b02a08a30 (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: Greg Kroah-Hartman <gregkh@suse.de>
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 944972e48f8..356f48722ef 100644 --- a/kernel/power/snapshot.c +++ b/kernel/power/snapshot.c @@ -1193,7 +1193,11 @@ 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); |