From: Nicholas Piggin <[email protected]>

commit 2da9f6305f306ffbbb44790675799328fb73119d upstream.

Previously the negated unsigned long would be cast back to signed long
which would have the correct negative value.  After commit 730ec8c01a2b
("mm/vmscan.c: change prototype for shrink_page_list"), the large
unsigned int converts to a large positive signed long.

Symptoms include CMA allocations hanging forever holding the cma_mutex
due to alloc_contig_range->...->isolate_migratepages_block waiting
forever in "while (unlikely(too_many_isolated(pgdat)))".

[[email protected]: fix -stat.nr_lazyfree_fail as well, per Michal]

Fixes: 730ec8c01a2b ("mm/vmscan.c: change prototype for shrink_page_list")
Signed-off-by: Nicholas Piggin <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Cc: Vaneet Narang <[email protected]>
Cc: Maninder Singh <[email protected]>
Cc: Amit Sahrawat <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

---
 mm/vmscan.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1514,7 +1514,8 @@ unsigned int reclaim_clean_pages_from_li
        nr_reclaimed = shrink_page_list(&clean_pages, zone->zone_pgdat, &sc,
                        TTU_IGNORE_ACCESS, &stat, true);
        list_splice(&clean_pages, page_list);
-       mod_node_page_state(zone->zone_pgdat, NR_ISOLATED_FILE, -nr_reclaimed);
+       mod_node_page_state(zone->zone_pgdat, NR_ISOLATED_FILE,
+                           -(long)nr_reclaimed);
        /*
         * Since lazyfree pages are isolated from file LRU from the beginning,
         * they will rotate back to anonymous LRU in the end if it failed to
@@ -1524,7 +1525,7 @@ unsigned int reclaim_clean_pages_from_li
        mod_node_page_state(zone->zone_pgdat, NR_ISOLATED_ANON,
                            stat.nr_lazyfree_fail);
        mod_node_page_state(zone->zone_pgdat, NR_ISOLATED_FILE,
-                           -stat.nr_lazyfree_fail);
+                           -(long)stat.nr_lazyfree_fail);
        return nr_reclaimed;
 }
 


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