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-rw-r--r--erts/emulator/test/nofrag_SUITE.erl5
-rw-r--r--lib/kernel/src/erts_debug.erl9
2 files changed, 14 insertions, 0 deletions
diff --git a/erts/emulator/test/nofrag_SUITE.erl b/erts/emulator/test/nofrag_SUITE.erl
index 8b1519ae36..d4c74579e2 100644
--- a/erts/emulator/test/nofrag_SUITE.erl
+++ b/erts/emulator/test/nofrag_SUITE.erl
@@ -22,6 +22,11 @@
-include_lib("common_test/include/ct.hrl").
+%% This suite alters the return values of functions which breaks certain
+%% assumptions made by the compiler, so we have to turn off module-level type
+%% optimization to be safe.
+-compile(no_module_opt).
+
-export([all/0, suite/0,
error_handler/1,error_handler_apply/1,
error_handler_fixed_apply/1,error_handler_fun/1,
diff --git a/lib/kernel/src/erts_debug.erl b/lib/kernel/src/erts_debug.erl
index 42261d371d..7b9067d079 100644
--- a/lib/kernel/src/erts_debug.erl
+++ b/lib/kernel/src/erts_debug.erl
@@ -40,6 +40,15 @@
lc_graph/0, lc_graph_to_dot/2, lc_graph_merge/2,
alloc_blocks_size/1]).
+%% Reroutes calls to the given MFA to error_handler:breakpoint/3
+%%
+%% Note that this is potentially unsafe as compiled code may assume that the
+%% targeted function returns a specific type, triggering undefined behavior if
+%% this function were to return something else.
+%%
+%% For reference, the debugger avoids the issue by purging the affected module
+%% and interpreting all functions in the module, ensuring that no assumptions
+%% are made with regard to return or argument types.
-spec breakpoint(MFA, Flag) -> non_neg_integer() when
MFA :: {Module :: module(),
Function :: atom(),