From 8a041377a4583850be020db01fd8f45bad0abaaf 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 [ Upstream commit d5d469247264e56960705dc5ae7e1d014861fe40 ] 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 Signed-off-by: Sasha Levin --- tools/objtool/check.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/tools/objtool/check.c b/tools/objtool/check.c index ff47aed7ef6f..5c4190382a51 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -864,6 +864,8 @@ 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",