From 29fbfedd806030a14d817132d29d6755e32daec7 Mon Sep 17 00:00:00 2001 From: John Naylor Date: Fri, 22 Mar 2024 13:01:33 +0700 Subject: [PATCH v20 1/3] Add macro to disable address safety instrumentation fasthash_accum_cstring_aligned() uses a technique, found in various strlen() implementations, to detect a string's NUL terminator by reading a word at at time. That triggers failures when testing with "-fsanitize=address", at least with frontend code. To enable using this function anywhere, add a function attribute macro to disable such testing. Reviewed by Discussion: https://postgr.es/m/CANWCAZbwvp7oUEkbw-xP4L0_S_WNKq-J-ucP4RCNDPJnrakUPw%40mail.gmail.com --- src/include/c.h | 13 +++++++++++++ src/include/common/hashfn_unstable.h | 5 ++++- 2 files changed, 17 insertions(+), 1 deletion(-) diff --git a/src/include/c.h b/src/include/c.h index cf37e02fe1..dc1841346c 100644 --- a/src/include/c.h +++ b/src/include/c.h @@ -135,6 +135,19 @@ #define pg_nodiscard #endif +/* + * This macro will disable address safety instrumentation for a function + * when running with "-fsanitize=address". Think twice before using this! + */ +#if defined(__clang__) || __GNUC__ >= 8 +#define pg_attribute_no_sanitize_address() __attribute__((no_sanitize("address"))) +#elif __has_attribute(no_sanitize_address) +/* This would work for clang, but it's deprecated. */ +#define pg_attribute_no_sanitize_address() __attribute__((no_sanitize_address)) +#else +#define pg_attribute_no_sanitize_address() +#endif + /* * Place this macro before functions that should be allowed to make misaligned * accesses. Think twice before using it on non-x86-specific code! diff --git a/src/include/common/hashfn_unstable.h b/src/include/common/hashfn_unstable.h index 791750d136..4227afd141 100644 --- a/src/include/common/hashfn_unstable.h +++ b/src/include/common/hashfn_unstable.h @@ -213,8 +213,11 @@ fasthash_accum_cstring_unaligned(fasthash_state *hs, const char *str) * * With an aligned pointer, we consume the string a word at a time. * Loading the word containing the NUL terminator cannot segfault since - * allocation boundaries are suitably aligned. + * allocation boundaries are suitably aligned. To keep from setting + * off alarms with address sanitizers, exclude this function from + * such testing. */ +pg_attribute_no_sanitize_address() static inline size_t fasthash_accum_cstring_aligned(fasthash_state *hs, const char *str) { -- 2.44.0