Hi, When running asan without further options against the backend, random tests fail because the stack-depth check fails. One can work around that by putting detect_stack_use_after_return=0 into ASAN_OPTIONS (at least with gcc, clang still uses a lot of stack, but i think that's a separate issue).
The reason for that breakage is that with the stack-use-after-return logic, stack variables are moved to heap allocations, to allow to detect references to the memory at a later time. That breaks our stack-depth check, which is why we had to disable detect_stack_use_after_return in CI. Luckily __builtin_frame_address() works correctly, even under asan, so use that. I think we should backpatch this. I'd be worried about using __builtin_frame_address(), but we already do, for the base address of the stack. Greetings, Andres Freund
>From 86c44c934d4aa0604f82f289a0b6bd6ec0c88e31 Mon Sep 17 00:00:00 2001 From: Andres Freund <[email protected]> Date: Sat, 7 Feb 2026 14:04:06 -0500 Subject: [PATCH v2 1/4] Make stack depth check work with asan's use-after-return With address sanitizer's stack-use-after-return check, stack variables are moved to heap allocations, to allow to detect references to the memory at a later time. That broke our stack-depth check, which is why we had to disable detect_stack_use_after_return in CI. Luckily __builtin_frame_address() works correctly, even under asan, so use that. Author: Reviewed-by: Discussion: https://postgr.es/m/ Backpatch: --- src/backend/utils/misc/stack_depth.c | 17 ++++++++++++++++- .cirrus.tasks.yml | 2 +- 2 files changed, 17 insertions(+), 2 deletions(-) diff --git a/src/backend/utils/misc/stack_depth.c b/src/backend/utils/misc/stack_depth.c index 61a07cf824e..9955e28c176 100644 --- a/src/backend/utils/misc/stack_depth.c +++ b/src/backend/utils/misc/stack_depth.c @@ -108,13 +108,28 @@ check_stack_depth(void) bool stack_is_too_deep(void) { +#ifndef HAVE__BUILTIN_FRAME_ADDRESS char stack_top_loc; +#endif ssize_t stack_depth; + char *stack_address; + + /* + * With address sanitizer's stack-use-after-return check, stack variables + * are moved to heap allocations, to allow to detect references to the + * memory at a later time. That would break our stack-depth check. Luckily + * __builtin_frame_address() works correctly, even under asan. + */ +#ifndef HAVE__BUILTIN_FRAME_ADDRESS + stack_address = &stack_top_loc; +#else + stack_address = (char *) __builtin_frame_address(0); +#endif /* * Compute distance from reference point to my local variables */ - stack_depth = (ssize_t) (stack_base_ptr - &stack_top_loc); + stack_depth = (ssize_t) (stack_base_ptr - stack_address); /* * Take abs value, since stacks grow up on some machines, down on others diff --git a/.cirrus.tasks.yml b/.cirrus.tasks.yml index a22cef063f3..8683d1ae9c7 100644 --- a/.cirrus.tasks.yml +++ b/.cirrus.tasks.yml @@ -447,7 +447,7 @@ task: # print_stacktraces=1,verbosity=2, duh # detect_leaks=0: too many uninteresting leak errors in short-lived binaries UBSAN_OPTIONS: print_stacktrace=1:disable_coredump=0:abort_on_error=1:verbosity=2 - ASAN_OPTIONS: print_stacktrace=1:disable_coredump=0:abort_on_error=1:detect_leaks=0:detect_stack_use_after_return=0 + ASAN_OPTIONS: print_stacktrace=1:disable_coredump=0:abort_on_error=1:detect_leaks=0 # SANITIZER_FLAGS is set in the tasks below CFLAGS: -Og -ggdb -fno-sanitize-recover=all $SANITIZER_FLAGS -- 2.53.0.1.gb2826b52eb
