diff options
author | Rafael J. Wysocki <rjw@sisk.pl> | 2011-07-06 14:15:23 -0400 |
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committer | Rafael J. Wysocki <rjw@sisk.pl> | 2011-07-06 14:15:23 -0400 |
commit | 4d4cf23cdde2f8f9324f5684a7f349e182039529 (patch) | |
tree | f84a26d15f1112cc7c452d1fdac3bd70857774e0 /kernel/power/snapshot.c | |
parent | a2fa83faf47b514ab947cea916d3691b66525073 (diff) |
PM / Hibernate: Fix free_unnecessary_pages()
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>
Cc: stable@kernel.org
Diffstat (limited to 'kernel/power/snapshot.c')
-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 ace55889f702..06efa54f93d6 100644 --- a/kernel/power/snapshot.c +++ b/kernel/power/snapshot.c | |||
@@ -1211,7 +1211,11 @@ static void free_unnecessary_pages(void) | |||
1211 | to_free_highmem = alloc_highmem - save; | 1211 | to_free_highmem = alloc_highmem - save; |
1212 | } else { | 1212 | } else { |
1213 | to_free_highmem = 0; | 1213 | to_free_highmem = 0; |
1214 | to_free_normal -= save - alloc_highmem; | 1214 | save -= alloc_highmem; |
1215 | if (to_free_normal > save) | ||
1216 | to_free_normal -= save; | ||
1217 | else | ||
1218 | to_free_normal = 0; | ||
1215 | } | 1219 | } |
1216 | 1220 | ||
1217 | memory_bm_position_reset(©_bm); | 1221 | memory_bm_position_reset(©_bm); |