From bbdd8895a5aced4cd4e66a5c6e3471636f28df6b Mon Sep 17 00:00:00 2001 From: Guido van Rossum Date: Sat, 26 Aug 2023 16:22:40 -0700 Subject: [3.12] gh-108487: Change assert that should've been DEOPT_IF (#108509) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit * Remove assert that should've been DEOPT_IF The assert(method != NULL) in CALL_NO_KW_LIST_APPEND is wrong -- this condition should lead to a deoptimization, and indeed there is a DEOPT_IF two lines later that will trigger if method == NULL. This would crash in a devious repro scenario (first seen live in boto3 tests) when compiled with assertions enabled. In a production version there is no crash, so impact is limited. (The crash also appears in main; I will prepare a separate PR.) * Add back a different assert(self != NULL) * 📜🤖 Added by blurb_it. --------- Co-authored-by: blurb-it[bot] <43283697+blurb-it[bot]@users.noreply.github.com> --- .../Core and Builtins/2023-08-26-04-33-18.gh-issue-108487.aUFxqf.rst | 1 + Python/bytecodes.c | 2 +- Python/generated_cases.c.h | 2 +- 3 files changed, 3 insertions(+), 2 deletions(-) create mode 100644 Misc/NEWS.d/next/Core and Builtins/2023-08-26-04-33-18.gh-issue-108487.aUFxqf.rst diff --git a/Misc/NEWS.d/next/Core and Builtins/2023-08-26-04-33-18.gh-issue-108487.aUFxqf.rst b/Misc/NEWS.d/next/Core and Builtins/2023-08-26-04-33-18.gh-issue-108487.aUFxqf.rst new file mode 100644 index 0000000..1117bcd --- /dev/null +++ b/Misc/NEWS.d/next/Core and Builtins/2023-08-26-04-33-18.gh-issue-108487.aUFxqf.rst @@ -0,0 +1 @@ +Change an assert that would cause a spurious crash in a devious case that should only trigger deoptimization. diff --git a/Python/bytecodes.c b/Python/bytecodes.c index dc2ae22..5e80e06 100644 --- a/Python/bytecodes.c +++ b/Python/bytecodes.c @@ -2992,9 +2992,9 @@ dummy_func( inst(CALL_NO_KW_LIST_APPEND, (unused/1, unused/2, method, self, args[oparg] -- unused)) { assert(kwnames == NULL); assert(oparg == 1); - assert(method != NULL); PyInterpreterState *interp = _PyInterpreterState_GET(); DEOPT_IF(method != interp->callable_cache.list_append, CALL); + assert(self != NULL); DEOPT_IF(!PyList_Check(self), CALL); STAT_INC(CALL, hit); if (_PyList_AppendTakeRef((PyListObject *)self, args[0]) < 0) { diff --git a/Python/generated_cases.c.h b/Python/generated_cases.c.h index b0a363c..a3c0495 100644 --- a/Python/generated_cases.c.h +++ b/Python/generated_cases.c.h @@ -4248,9 +4248,9 @@ #line 2993 "Python/bytecodes.c" assert(kwnames == NULL); assert(oparg == 1); - assert(method != NULL); PyInterpreterState *interp = _PyInterpreterState_GET(); DEOPT_IF(method != interp->callable_cache.list_append, CALL); + assert(self != NULL); DEOPT_IF(!PyList_Check(self), CALL); STAT_INC(CALL, hit); if (_PyList_AppendTakeRef((PyListObject *)self, args[0]) < 0) { -- cgit v0.12