From: Marco Elver <elver@xxxxxxxxxx> Subject: kasan: remove mentions of unsupported Clang versions Since the kernel now requires at least Clang 10.0.1, remove any mention of old Clang versions and simplify the documentation. Link: https://lkml.kernel.org/r/20200902225911.209899-7-ndesaulniers@xxxxxxxxxx Signed-off-by: Marco Elver <elver@xxxxxxxxxx> Signed-off-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx> Reviewed-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx> Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx> Reviewed-by: Nathan Chancellor <natechancellor@xxxxxxxxx> Cc: Fangrui Song <maskray@xxxxxxxxxx> Cc: Miguel Ojeda <miguel.ojeda.sandonis@xxxxxxxxx> Cc: Sedat Dilek <sedat.dilek@xxxxxxxxx> Cc: Alexei Starovoitov <ast@xxxxxxxxxx> Cc: Daniel Borkmann <daniel@xxxxxxxxxxxxx> Cc: Masahiro Yamada <masahiroy@xxxxxxxxxx> Cc: Vincenzo Frascino <vincenzo.frascino@xxxxxxx> Cc: Will Deacon <will@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- Documentation/dev-tools/kasan.rst | 4 ++-- lib/Kconfig.kasan | 9 ++++----- 2 files changed, 6 insertions(+), 7 deletions(-) --- a/Documentation/dev-tools/kasan.rst~kasan-remove-mentions-of-unsupported-clang-versions +++ a/Documentation/dev-tools/kasan.rst @@ -13,10 +13,10 @@ KASAN uses compile-time instrumentation memory access, and therefore requires a compiler version that supports that. Generic KASAN is supported in both GCC and Clang. With GCC it requires version -8.3.0 or later. With Clang it requires version 7.0.0 or later, but detection of +8.3.0 or later. Any supported Clang version is compatible, but detection of out-of-bounds accesses for global variables is only supported since Clang 11. -Tag-based KASAN is only supported in Clang and requires version 7.0.0 or later. +Tag-based KASAN is only supported in Clang. Currently generic KASAN is supported for the x86_64, arm64, xtensa, s390 and riscv architectures, and tag-based KASAN is supported only for arm64. --- a/lib/Kconfig.kasan~kasan-remove-mentions-of-unsupported-clang-versions +++ a/lib/Kconfig.kasan @@ -54,9 +54,9 @@ config KASAN_GENERIC Enables generic KASAN mode. This mode is supported in both GCC and Clang. With GCC it requires - version 8.3.0 or later. With Clang it requires version 7.0.0 or - later, but detection of out-of-bounds accesses for global variables - is supported only since Clang 11. + version 8.3.0 or later. Any supported Clang version is compatible, + but detection of out-of-bounds accesses for global variables is + supported only since Clang 11. This mode consumes about 1/8th of available memory at kernel start and introduces an overhead of ~x1.5 for the rest of the allocations. @@ -78,8 +78,7 @@ config KASAN_SW_TAGS Enables software tag-based KASAN mode. This mode requires Top Byte Ignore support by the CPU and therefore - is only supported for arm64. This mode requires Clang version 7.0.0 - or later. + is only supported for arm64. This mode requires Clang. This mode consumes about 1/16th of available memory at kernel start and introduces an overhead of ~20% for the rest of the allocations. _
