From 0d550c80d4f19cc432e7de056169695d436c02a0 Mon Sep 17 00:00:00 2001 From: Sverker Eriksson Date: Mon, 11 Mar 2019 15:51:45 +0100 Subject: erts: Fix ets:select table fixation leak at owner change Symtom: ETS table remains fixed after finished ets:select* call. Problem: The decision to unfix table after a yielding ets:select* is based on table ownership, but ownership might have changed while ets:select* was yielding. Solution: Remember and pass along whether table was fixed when the traversal started. --- erts/emulator/beam/erl_db.c | 72 +++++++++++++++++++++++++-------------------- 1 file changed, 40 insertions(+), 32 deletions(-) (limited to 'erts/emulator/beam/erl_db.c') diff --git a/erts/emulator/beam/erl_db.c b/erts/emulator/beam/erl_db.c index 4132a54934..0a50af4d1a 100644 --- a/erts/emulator/beam/erl_db.c +++ b/erts/emulator/beam/erl_db.c @@ -81,14 +81,6 @@ static BIF_RETTYPE db_bif_fail(Process* p, Uint freason, /* Get a key from any table structure and a tagged object */ #define TERM_GETKEY(tb, obj) db_getkey((tb)->common.keypos, (obj)) - -/* How safe are we from double-hits or missed objects -** when iterating without fixation? */ -enum DbIterSafety { - ITER_UNSAFE, /* Must fixate to be safe */ - ITER_SAFE_LOCKED, /* Safe while table is locked, not between trap calls */ - ITER_SAFE /* No need to fixate at all */ -}; # define ITERATION_SAFETY(Proc,Tab) \ ((IS_TREE_TABLE((Tab)->common.status) || IS_CATREE_TABLE((Tab)->common.status) \ || ONLY_WRITER(Proc,Tab)) ? ITER_SAFE \ @@ -195,9 +187,6 @@ static int fixed_tabs_find(DbFixation* first, DbFixation* fix) #define ERTS_RBT_WANT_DELETE #define ERTS_RBT_WANT_FOREACH #define ERTS_RBT_WANT_FOREACH_DESTROY -#ifdef DEBUG -# define ERTS_RBT_WANT_LOOKUP -#endif #define ERTS_RBT_UNDEF #include "erl_rbtree.h" @@ -2287,6 +2276,7 @@ static BIF_RETTYPE ets_select_delete_trap_1(BIF_ALIST_1) Eterm ret; Eterm *tptr; db_lock_kind_t kind = LCK_WRITE_REC; + enum DbIterSafety safety = ITER_SAFE; CHECK_TABLES(); ASSERT(is_tuple(a1)); @@ -2296,10 +2286,11 @@ static BIF_RETTYPE ets_select_delete_trap_1(BIF_ALIST_1) DB_TRAP_GET_TABLE(tb, tptr[1], DB_WRITE, kind, &ets_select_delete_continue_exp); - cret = tb->common.meth->db_select_delete_continue(p,tb,a1,&ret); + cret = tb->common.meth->db_select_delete_continue(p,tb,a1,&ret,&safety); - if(!DID_TRAP(p,ret) && ITERATION_SAFETY(p,tb) != ITER_SAFE) { - unfix_table_locked(p, tb, &kind); + if(!DID_TRAP(p,ret) && safety != ITER_SAFE) { + ASSERT(erts_refc_read(&tb->common.fix_count,1)); + unfix_table_locked(p, tb, &kind); } db_unlock(tb, kind); @@ -2337,7 +2328,8 @@ BIF_RETTYPE ets_internal_select_delete_2(BIF_ALIST_2) if (safety == ITER_UNSAFE) { local_fix_table(tb); } - cret = tb->common.meth->db_select_delete(BIF_P, tb, BIF_ARG_1, BIF_ARG_2, &ret); + cret = tb->common.meth->db_select_delete(BIF_P, tb, BIF_ARG_1, BIF_ARG_2, + &ret, safety); if (DID_TRAP(BIF_P,ret) && safety != ITER_SAFE) { fix_table_locked(BIF_P,tb); @@ -2729,7 +2721,7 @@ ets_select3(Process* p, DbTable* tb, Eterm tid, Eterm ms, Sint chunk_size) cret = tb->common.meth->db_select_chunk(p, tb, tid, ms, chunk_size, 0 /* not reversed */, - &ret); + &ret, safety); if (DID_TRAP(p,ret) && safety != ITER_SAFE) { fix_table_locked(p, tb); } @@ -2756,7 +2748,8 @@ ets_select3(Process* p, DbTable* tb, Eterm tid, Eterm ms, Sint chunk_size) } -/* We get here instead of in the real BIF when trapping */ +/* Trap here from: ets_select_1/2/3 + */ static BIF_RETTYPE ets_select_trap_1(BIF_ALIST_1) { Process *p = BIF_P; @@ -2767,6 +2760,7 @@ static BIF_RETTYPE ets_select_trap_1(BIF_ALIST_1) Eterm ret; Eterm *tptr; db_lock_kind_t kind = LCK_READ; + enum DbIterSafety safety = ITER_SAFE; CHECK_TABLES(); @@ -2776,11 +2770,13 @@ static BIF_RETTYPE ets_select_trap_1(BIF_ALIST_1) DB_TRAP_GET_TABLE(tb, tptr[1], DB_READ, kind, &ets_select_continue_exp); - cret = tb->common.meth->db_select_continue(p, tb, a1, - &ret); + cret = tb->common.meth->db_select_continue(p, tb, a1, &ret, &safety); - if (!DID_TRAP(p,ret) && ITERATION_SAFETY(p,tb) != ITER_SAFE) { - unfix_table_locked(p, tb, &kind); + if (!DID_TRAP(p,ret)) { + if (safety != ITER_SAFE) { + ASSERT(erts_refc_read(&tb->common.fix_count,1)); + unfix_table_locked(p, tb, &kind); + } } db_unlock(tb, kind); @@ -2805,8 +2801,12 @@ static BIF_RETTYPE ets_select_trap_1(BIF_ALIST_1) BIF_RETTYPE ets_select_1(BIF_ALIST_1) { return ets_select1(BIF_P, BIF_ets_select_1, BIF_ARG_1); + /* TRAP: ets_select_trap_1 */ } +/* + * Common impl for select/1, select_reverse/1, match/1 and match_object/1 + */ static BIF_RETTYPE ets_select1(Process *p, int bif_ix, Eterm arg1) { BIF_RETTYPE result; @@ -2814,7 +2814,7 @@ static BIF_RETTYPE ets_select1(Process *p, int bif_ix, Eterm arg1) int cret; Eterm ret; Eterm *tptr; - enum DbIterSafety safety; + enum DbIterSafety safety, safety_copy; CHECK_TABLES(); @@ -2839,7 +2839,8 @@ static BIF_RETTYPE ets_select1(Process *p, int bif_ix, Eterm arg1) local_fix_table(tb); } - cret = tb->common.meth->db_select_continue(p,tb, arg1, &ret); + safety_copy = safety; + cret = tb->common.meth->db_select_continue(p,tb, arg1, &ret, &safety_copy); if (DID_TRAP(p,ret) && safety != ITER_SAFE) { fix_table_locked(p, tb); @@ -2871,6 +2872,7 @@ BIF_RETTYPE ets_select_2(BIF_ALIST_2) DbTable* tb; DB_BIF_GET_TABLE(tb, DB_READ, LCK_READ, BIF_ets_select_2); return ets_select2(BIF_P, tb, BIF_ARG_1, BIF_ARG_2); + /* TRAP: ets_select_trap_1 */ } static BIF_RETTYPE @@ -2888,7 +2890,7 @@ ets_select2(Process* p, DbTable* tb, Eterm tid, Eterm ms) local_fix_table(tb); } - cret = tb->common.meth->db_select(p, tb, tid, ms, 0, &ret); + cret = tb->common.meth->db_select(p, tb, tid, ms, 0, &ret, safety); if (DID_TRAP(p,ret) && safety != ITER_SAFE) { fix_table_locked(p, tb); @@ -2926,6 +2928,7 @@ static BIF_RETTYPE ets_select_count_1(BIF_ALIST_1) Eterm ret; Eterm *tptr; db_lock_kind_t kind = LCK_READ; + enum DbIterSafety safety = ITER_SAFE; CHECK_TABLES(); @@ -2935,9 +2938,10 @@ static BIF_RETTYPE ets_select_count_1(BIF_ALIST_1) DB_TRAP_GET_TABLE(tb, tptr[1], DB_READ, kind, &ets_select_count_continue_exp); - cret = tb->common.meth->db_select_count_continue(p, tb, a1, &ret); + cret = tb->common.meth->db_select_count_continue(p, tb, a1, &ret, &safety); - if (!DID_TRAP(p,ret) && ITERATION_SAFETY(p,tb) != ITER_SAFE) { + if (!DID_TRAP(p,ret) && safety != ITER_SAFE) { + ASSERT(erts_refc_read(&tb->common.fix_count,1)); unfix_table_locked(p, tb, &kind); } db_unlock(tb, kind); @@ -2975,7 +2979,8 @@ BIF_RETTYPE ets_select_count_2(BIF_ALIST_2) if (safety == ITER_UNSAFE) { local_fix_table(tb); } - cret = tb->common.meth->db_select_count(BIF_P,tb, BIF_ARG_1, BIF_ARG_2, &ret); + cret = tb->common.meth->db_select_count(BIF_P,tb, BIF_ARG_1, BIF_ARG_2, + &ret, safety); if (DID_TRAP(BIF_P,ret) && safety != ITER_SAFE) { fix_table_locked(BIF_P, tb); @@ -3014,6 +3019,7 @@ static BIF_RETTYPE ets_select_replace_1(BIF_ALIST_1) Eterm ret; Eterm *tptr; db_lock_kind_t kind = LCK_WRITE_REC; + enum DbIterSafety safety = ITER_SAFE; CHECK_TABLES(); ASSERT(is_tuple(a1)); @@ -3023,9 +3029,10 @@ static BIF_RETTYPE ets_select_replace_1(BIF_ALIST_1) DB_TRAP_GET_TABLE(tb, tptr[1], DB_WRITE, kind, &ets_select_replace_continue_exp); - cret = tb->common.meth->db_select_replace_continue(p,tb,a1,&ret); + cret = tb->common.meth->db_select_replace_continue(p,tb,a1,&ret,&safety); - if(!DID_TRAP(p,ret) && ITERATION_SAFETY(p,tb) != ITER_SAFE) { + if(!DID_TRAP(p,ret) && safety != ITER_SAFE) { + ASSERT(erts_refc_read(&tb->common.fix_count,1)); unfix_table_locked(p, tb, &kind); } @@ -3068,7 +3075,8 @@ BIF_RETTYPE ets_select_replace_2(BIF_ALIST_2) if (safety == ITER_UNSAFE) { local_fix_table(tb); } - cret = tb->common.meth->db_select_replace(BIF_P, tb, BIF_ARG_1, BIF_ARG_2, &ret); + cret = tb->common.meth->db_select_replace(BIF_P, tb, BIF_ARG_1, BIF_ARG_2, + &ret, safety); if (DID_TRAP(BIF_P,ret) && safety != ITER_SAFE) { fix_table_locked(BIF_P,tb); @@ -3120,7 +3128,7 @@ BIF_RETTYPE ets_select_reverse_3(BIF_ALIST_3) } cret = tb->common.meth->db_select_chunk(BIF_P,tb, BIF_ARG_1, BIF_ARG_2, chunk_size, - 1 /* reversed */, &ret); + 1 /* reversed */, &ret, safety); if (DID_TRAP(BIF_P,ret) && safety != ITER_SAFE) { fix_table_locked(BIF_P, tb); } @@ -3165,7 +3173,7 @@ BIF_RETTYPE ets_select_reverse_2(BIF_ALIST_2) local_fix_table(tb); } cret = tb->common.meth->db_select(BIF_P,tb, BIF_ARG_1, BIF_ARG_2, - 1 /*reversed*/, &ret); + 1 /*reversed*/, &ret, safety); if (DID_TRAP(BIF_P,ret) && safety != ITER_SAFE) { fix_table_locked(BIF_P, tb); -- cgit v1.2.3