This is a note to let you know that I've just added the patch titled objtool: add UACCESS exceptions for __tsan_volatile_read/write to the 5.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: objtool-add-uaccess-exceptions-for-__tsan_volatile_r.patch and it can be found in the queue-5.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 2194b3a4d5b9cd081916548d5bdea46517008114 Author: Arnd Bergmann <arnd@xxxxxxxx> Date: Wed Feb 15 14:00:58 2023 +0100 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@xxxxxxxxxx Fixes: 75d75b7a4d54 ("kcsan: Support distinguishing volatile accesses") Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx> Acked-by: Marco Elver <elver@xxxxxxxxxx> Cc: Alexander Potapenko <glider@xxxxxxxxxx> Cc: Andrey Konovalov <andreyknvl@xxxxxxxxx> Cc: Andrey Ryabinin <ryabinin.a.a@xxxxxxxxx> Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx> Cc: Josh Poimboeuf <jpoimboe@xxxxxxxxxx> Cc: Kuan-Ying Lee <Kuan-Ying.Lee@xxxxxxxxxxxx> Cc: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Cc: Vincenzo Frascino <vincenzo.frascino@xxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 3ef767284b3f0..2fc0270e3c1f7 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -908,6 +908,8 @@ 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",