maple_tree: Fix overwritten slot in mas during __mas_add

Overwriting the slot in the ma state caused issues later on.  Restore
the value and fix the code in mas_may_move_gap to also detect such
scenarios.

Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index 3a2ad10b4e5caff914720f08762e2500118f1e17..96ccb175711b23aabb5719b020bfd2e0b175f427 100644 (file)
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -1329,6 +1329,7 @@ static inline unsigned char _mas_append(struct ma_state *mas,
                                this_piv = ma_get_pivot(smn, src_end, stype);
                }
 
+               // Not really src_data..
                src_data = mas_get_rcu_slot(mas, dst_slot);
                if (!src_data) {
                        if (!this_piv)
@@ -2228,14 +2229,14 @@ static inline void mas_may_move_gap(struct ma_state *mas)
        if (entry && !xa_is_deleted(entry))
                return;
 
-       if (curr.node == mas->node) {
+       if (curr.node == mas->node)
                mas_next(&next, ULONG_MAX);
-               if (mas_is_none(&next))
-                       return;
 
-               if (!mt_is_empty(mas_get_rcu_slot(&next, 0)))
-                       return;
-       }
+       if (mas_is_none(&next))
+               return;
+
+       if (!mt_is_empty(mas_get_rcu_slot(&next, 0)))
+               return;
 
        while (end && (!entry || xa_is_deleted(entry)))
                entry = mas_get_rcu_slot(&curr, --end);
@@ -2713,6 +2714,7 @@ static inline int _mas_add(struct ma_state *mas, void *entry, bool overwrite,
 
        mas_set_slot(mas, slot);
        __mas_add(mas, entry, old_end, active, append);
+       mas_set_slot(mas, slot);
 
 complete:
        if (prev_enode != mas->node)

diff --git a/lib/test_maple_tree.c b/lib/test_maple_tree.c
index a9f5ba3b57ac456b66ab05522a174af853ab72fb..3b4945c69f9c6a18f5621d687767c32aa5b00d8c 100644 (file)
--- a/lib/test_maple_tree.c
+++ b/lib/test_maple_tree.c
@@ -10601,6 +10601,167 @@ STORE, 140656836775936, 140656836780031,
 STORE, 140656787476480, 140656791920639,
 ERASE, 140656774639616, 140656779083775,
        };
+       unsigned long set20[] = {
+STORE, 140737488347136, 140737488351231,
+STORE, 140735952392192, 140737488351231,
+SNULL, 140735952396287, 140737488351231,
+STORE, 140735952392192, 140735952396287,
+STORE, 140735952261120, 140735952396287,
+STORE, 94849008947200, 94849009414143,
+SNULL, 94849009364991, 94849009414143,
+STORE, 94849008947200, 94849009364991,
+STORE, 94849009364992, 94849009414143,
+ERASE, 94849009364992, 94849009414143,
+STORE, 94849009364992, 94849009414143,
+STORE, 140590397943808, 140590400196607,
+SNULL, 140590398087167, 140590400196607,
+STORE, 140590397943808, 140590398087167,
+STORE, 140590398087168, 140590400196607,
+ERASE, 140590398087168, 140590400196607,
+STORE, 140590400184320, 140590400192511,
+STORE, 140590400192512, 140590400196607,
+STORE, 140735952850944, 140735952855039,
+STORE, 140735952838656, 140735952850943,
+STORE, 140590400180224, 140590400184319,
+STORE, 140590400172032, 140590400180223,
+STORE, 140590395809792, 140590397943807,
+SNULL, 140590395809792, 140590395838463,
+STORE, 140590395838464, 140590397943807,
+STORE, 140590395809792, 140590395838463,
+SNULL, 140590397935615, 140590397943807,
+STORE, 140590395838464, 140590397935615,
+STORE, 140590397935616, 140590397943807,
+ERASE, 140590397935616, 140590397943807,
+STORE, 140590397935616, 140590397943807,
+STORE, 140590393425920, 140590395809791,
+SNULL, 140590393425920, 140590393692159,
+STORE, 140590393692160, 140590395809791,
+STORE, 140590393425920, 140590393692159,
+SNULL, 140590395785215, 140590395809791,
+STORE, 140590393692160, 140590395785215,
+STORE, 140590395785216, 140590395809791,
+SNULL, 140590395785216, 140590395805695,
+STORE, 140590395805696, 140590395809791,
+STORE, 140590395785216, 140590395805695,
+ERASE, 140590395785216, 140590395805695,
+STORE, 140590395785216, 140590395805695,
+ERASE, 140590395805696, 140590395809791,
+STORE, 140590395805696, 140590395809791,
+STORE, 140590391234560, 140590393425919,
+SNULL, 140590391234560, 140590391324671,
+STORE, 140590391324672, 140590393425919,
+STORE, 140590391234560, 140590391324671,
+SNULL, 140590393417727, 140590393425919,
+STORE, 140590391324672, 140590393417727,
+STORE, 140590393417728, 140590393425919,
+ERASE, 140590393417728, 140590393425919,
+STORE, 140590393417728, 140590393425919,
+STORE, 140590388973568, 140590391234559,
+SNULL, 140590388973568, 140590389125119,
+STORE, 140590389125120, 140590391234559,
+STORE, 140590388973568, 140590389125119,
+SNULL, 140590391218175, 140590391234559,
+STORE, 140590389125120, 140590391218175,
+STORE, 140590391218176, 140590391234559,
+SNULL, 140590391218176, 140590391226367,
+STORE, 140590391226368, 140590391234559,
+STORE, 140590391218176, 140590391226367,
+ERASE, 140590391218176, 140590391226367,
+STORE, 140590391218176, 140590391226367,
+ERASE, 140590391226368, 140590391234559,
+STORE, 140590391226368, 140590391234559,
+STORE, 140590386843648, 140590388973567,
+SNULL, 140590386843648, 140590386872319,
+STORE, 140590386872320, 140590388973567,
+STORE, 140590386843648, 140590386872319,
+SNULL, 140590388965375, 140590388973567,
+STORE, 140590386872320, 140590388965375,
+STORE, 140590388965376, 140590388973567,
+ERASE, 140590388965376, 140590388973567,
+STORE, 140590388965376, 140590388973567,
+STORE, 140590384627712, 140590386843647,
+SNULL, 140590384627712, 140590384726015,
+STORE, 140590384726016, 140590386843647,
+STORE, 140590384627712, 140590384726015,
+SNULL, 140590386819071, 140590386843647,
+STORE, 140590384726016, 140590386819071,
+STORE, 140590386819072, 140590386843647,
+SNULL, 140590386819072, 140590386827263,
+STORE, 140590386827264, 140590386843647,
+STORE, 140590386819072, 140590386827263,
+ERASE, 140590386819072, 140590386827263,
+STORE, 140590386819072, 140590386827263,
+ERASE, 140590386827264, 140590386843647,
+STORE, 140590386827264, 140590386843647,
+STORE, 140590400163840, 140590400180223,
+STORE, 140590380830720, 140590384627711,
+SNULL, 140590380830720, 140590382489599,
+STORE, 140590382489600, 140590384627711,
+STORE, 140590380830720, 140590382489599,
+SNULL, 140590384586751, 140590384627711,
+STORE, 140590382489600, 140590384586751,
+STORE, 140590384586752, 140590384627711,
+SNULL, 140590384586752, 140590384611327,
+STORE, 140590384611328, 140590384627711,
+STORE, 140590384586752, 140590384611327,
+ERASE, 140590384586752, 140590384611327,
+STORE, 140590384586752, 140590384611327,
+ERASE, 140590384611328, 140590384627711,
+STORE, 140590384611328, 140590384627711,
+STORE, 140590378713088, 140590380830719,
+SNULL, 140590378713088, 140590378729471,
+STORE, 140590378729472, 140590380830719,
+STORE, 140590378713088, 140590378729471,
+SNULL, 140590380822527, 140590380830719,
+STORE, 140590378729472, 140590380822527,
+STORE, 140590380822528, 140590380830719,
+ERASE, 140590380822528, 140590380830719,
+STORE, 140590380822528, 140590380830719,
+STORE, 140590376595456, 140590378713087,
+SNULL, 140590376595456, 140590376611839,
+STORE, 140590376611840, 140590378713087,
+STORE, 140590376595456, 140590376611839,
+SNULL, 140590378704895, 140590378713087,
+STORE, 140590376611840, 140590378704895,
+STORE, 140590378704896, 140590378713087,
+ERASE, 140590378704896, 140590378713087,
+STORE, 140590378704896, 140590378713087,
+STORE, 140590374027264, 140590376595455,
+SNULL, 140590374027264, 140590374494207,
+STORE, 140590374494208, 140590376595455,
+STORE, 140590374027264, 140590374494207,
+SNULL, 140590376587263, 140590376595455,
+STORE, 140590374494208, 140590376587263,
+STORE, 140590376587264, 140590376595455,
+ERASE, 140590376587264, 140590376595455,
+STORE, 140590376587264, 140590376595455,
+STORE, 140590371913728, 140590374027263,
+SNULL, 140590371913728, 140590371926015,
+STORE, 140590371926016, 140590374027263,
+STORE, 140590371913728, 140590371926015,
+SNULL, 140590374019071, 140590374027263,
+STORE, 140590371926016, 140590374019071,
+STORE, 140590374019072, 140590374027263,
+ERASE, 140590374019072, 140590374027263,
+STORE, 140590374019072, 140590374027263,
+STORE, 140590400155648, 140590400180223,
+STORE, 140590400143360, 140590400180223,
+SNULL, 140590384603135, 140590384611327,
+STORE, 140590384586752, 140590384603135,
+STORE, 140590384603136, 140590384611327,
+SNULL, 140590374023167, 140590374027263,
+STORE, 140590374019072, 140590374023167,
+STORE, 140590374023168, 140590374027263,
+SNULL, 140590386823167, 140590386827263,
+STORE, 140590386819072, 140590386823167,
+STORE, 140590386823168, 140590386827263,
+SNULL, 140590376591359, 140590376595455,
+/*
+STORE, 140590376587264, 140590376591359,
+STORE, 140590376591360, 140590376595455,
+*/
+       };
+
 
        int cnt = 0;
        MA_STATE(mas, mt, 0, 0);
@@ -10756,6 +10917,16 @@ ERASE, 140656774639616, 140656779083775,
        entry = mas_prev(&mas, 0);
        MT_BUG_ON(mt, entry != xa_mk_value(140656766251008));
        mtree_destroy(mt);
+
+       /* set20 found a bug in mas_may_move_gap due to the slot being
+        * overwritten during the __mas_add operation and setting it to zero.
+        */
+       mt_set_non_kernel(99);
+       mtree_init(mt, MAPLE_ALLOC_RANGE);
+       check_erase2_testset(mt, set20, ARRAY_SIZE(set20));
+       rcu_barrier();
+       check_load(mt, 94849009414144, NULL);
+       mtree_destroy(mt);
 }
 
 static noinline void check_alloc_rev_range(struct maple_tree *mt)
@@ -11171,7 +11342,9 @@ static noinline void check_gap_combining(struct maple_tree *mt)
        check_seq(mt, 100, false); // create 100 singletons.
 
        mtree_test_erase(mt, 88);
+       check_load(mt, 88, NULL);
        mtree_test_erase(mt, 87);
+       check_load(mt, 87, NULL);
 
        rcu_read_lock();
        entry = mas_find(&mas, ULONG_MAX);
@@ -11190,7 +11363,9 @@ static noinline void check_gap_combining(struct maple_tree *mt)
        rcu_read_unlock();
 
        mtree_test_erase(mt, 38);
+       check_load(mt, 38, NULL);
        mtree_test_erase(mt, 39);
+       check_load(mt, 39, NULL);
        mtree_test_erase(mt, 40);
        index = 37;
 
@@ -11214,7 +11389,11 @@ static noinline void check_gap_combining(struct maple_tree *mt)
        rcu_read_unlock();
 
        mtree_store(mt, 79, NULL, GFP_KERNEL);
+       check_load(mt, 79, NULL);
+       check_load(mt, 80, xa_mk_value(80));
        mtree_store(mt, 80, NULL, GFP_KERNEL);
+       check_load(mt, 79, NULL);
+       check_load(mt, 80, NULL);
 
        mas_reset(&mas);
        rcu_read_lock();