diff options
Diffstat (limited to 'mm/compaction.c')
| -rw-r--r-- | mm/compaction.c | 19 |
1 files changed, 15 insertions, 4 deletions
diff --git a/mm/compaction.c b/mm/compaction.c index 14d2fe231ea4..86375605faa9 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -1401,7 +1401,7 @@ fast_isolate_freepages(struct compact_control *cc) if (scan_start) { /* * Use the highest PFN found above min. If one was - * not found, be pessemistic for direct compaction + * not found, be pessimistic for direct compaction * and use the min mark. */ if (highest) { @@ -2316,15 +2316,26 @@ static enum compact_result compact_zone_order(struct zone *zone, int order, .page = NULL, }; - current->capture_control = &capc; + /* + * Make sure the structs are really initialized before we expose the + * capture control, in case we are interrupted and the interrupt handler + * frees a page. + */ + barrier(); + WRITE_ONCE(current->capture_control, &capc); ret = compact_zone(&cc, &capc); VM_BUG_ON(!list_empty(&cc.freepages)); VM_BUG_ON(!list_empty(&cc.migratepages)); - *capture = capc.page; - current->capture_control = NULL; + /* + * Make sure we hide capture control first before we read the captured + * page pointer, otherwise an interrupt could free and capture a page + * and we would leak it. + */ + WRITE_ONCE(current->capture_control, NULL); + *capture = READ_ONCE(capc.page); return ret; } |