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Fix #1174 - bad debug info causing stack traversal to segfault.

Coming from commit 77189b6e66, relating
to changes in source mapping debug info, this caused a segfault when
traversing a stack frame where the birth_pc was incredibly large due
to wrap around. This fix prevents the wrap around and does saturating
subtraction to 0.
This commit is contained in:
Calvin Rose 2023-06-01 13:01:59 -05:00
parent 26a113927e
commit e97299fc65
2 changed files with 19 additions and 1 deletions

View File

@ -978,7 +978,14 @@ JanetFuncDef *janetc_pop_funcdef(JanetCompiler *c) {
jsm.death_pc = pair.death_pc - scope->bytecode_start;
}
/* Handle birth_pc == 0 correctly */
jsm.birth_pc = pair.birth_pc ? pair.birth_pc - scope->bytecode_start : 0;
if ((uint32_t) scope->bytecode_start > pair.birth_pc) {
jsm.birth_pc = 0;
} else {
jsm.birth_pc = pair.birth_pc - scope->bytecode_start;
}
janet_assert(jsm.birth_pc <= jsm.death_pc, "birth pc after death pc");
janet_assert(jsm.birth_pc < (uint32_t) def->bytecode_length, "bad birth pc");
janet_assert(jsm.death_pc <= (uint32_t) def->bytecode_length, "bad death pc");
jsm.slot_index = pair.slot.index;
jsm.symbol = pair.sym2;
janet_v_push(locals, jsm);

View File

@ -47,4 +47,15 @@
(assert (= 10 (do (var x 10) (def y x) (++ x) y)) "no invalid aliasing")
# Crash issue #1174 - bad debug info
(defn crash []
(debug/stack (fiber/current)))
(do
(math/random)
(defn foo [_]
(crash)
1)
(foo 0)
10)
(end-suite)