From 3cff5b0274e31c62b07c9015b874dd3b4f64b92e Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Wed, 15 Feb 2023 14:00:58 +0100 Subject: [PATCH] objtool: add UACCESS exceptions for __tsan_volatile_read/write A lot of the tsan helpers are already excempt from the UACCESS warnings, but some more functions were added that need the same thing: kernel/kcsan/core.o: warning: objtool: __tsan_volatile_read16+0x0: call to __tsan_unaligned_read16() with UACCESS enabled kernel/kcsan/core.o: warning: objtool: __tsan_volatile_write16+0x0: call to __tsan_unaligned_write16() with UACCESS enabled vmlinux.o: warning: objtool: __tsan_unaligned_volatile_read16+0x4: call to __tsan_unaligned_read16() with UACCESS enabled vmlinux.o: warning: objtool: __tsan_unaligned_volatile_write16+0x4: call to __tsan_unaligned_write16() with UACCESS enabled As Marco points out, these functions don't even call each other explicitly but instead gcc (but not clang) notices the functions being identical and turns one symbol into a direct branch to the other. Link: https://lkml.kernel.org/r/20230215130058.3836177-4-arnd@kernel.org Fixes: 75d75b7a4d54 ("kcsan: Support distinguishing volatile accesses") Signed-off-by: Arnd Bergmann Acked-by: Marco Elver Cc: Alexander Potapenko Cc: Andrey Konovalov Cc: Andrey Ryabinin Cc: Dmitry Vyukov Cc: Josh Poimboeuf Cc: Kuan-Ying Lee Cc: Peter Zijlstra (Intel) Cc: Vincenzo Frascino Signed-off-by: Andrew Morton --- tools/objtool/check.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 4b7c8b33069e5..b1a5f658673f0 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -1186,6 +1186,8 @@ static const char *uaccess_safe_builtin[] = { "__tsan_atomic64_compare_exchange_val", "__tsan_atomic_thread_fence", "__tsan_atomic_signal_fence", + "__tsan_unaligned_read16", + "__tsan_unaligned_write16", /* KCOV */ "write_comp_data", "check_kcov_mode",