From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f73.google.com (mail-wm1-f73.google.com [209.85.128.73]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E720A358383 for ; Thu, 12 Mar 2026 18:20:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.73 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773339628; cv=none; b=tt3S+GzheOzk9fYdzNeaMt2+eGBeKwA+lTXWccXTCvf2r/n+7GL6AXDXC67MuQSYSVYyC6gXDuf1H8zz184G9OOQX8ljBEGnAt06iCLZQdNBrlqypP6QneyUhgzJy+kloMhmUzokq6BFZcLVI5IGj9o9uxLGCvVl6bulamJZG08= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773339628; c=relaxed/simple; bh=A+A+tratlevD3a3rMI2wmVXp/n07E7eNLHxYMsuqPio=; h=Date:Mime-Version:Message-ID:Subject:From:To:Cc:Content-Type; b=PtmZl+x7FvmLwtIb4mTrYGstXS69iX1qDTTlmlb7TW5Y/1RRGgVqNH3youQvWXAX902qpRCXsc/Jgzvyl0bU5iHaLbwYSLZtCFyrbfRVuZKjN/jSqgq88ydVnvMzRk03mE4O4aUXXa3stnaNqrAcEQfQwF7Kk1WwIyK5uOaiDOI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--vdonnefort.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=ifNmJSim; arc=none smtp.client-ip=209.85.128.73 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--vdonnefort.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="ifNmJSim" Received: by mail-wm1-f73.google.com with SMTP id 5b1f17b1804b1-4852cf0318dso14173135e9.3 for ; Thu, 12 Mar 2026 11:20:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1773339623; x=1773944423; darn=vger.kernel.org; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=dK9k5DTKgk7wxx2+4cg6YZWZrym/c7pdTbONfQY+9AY=; b=ifNmJSimEe6j+RUMA9aOJsI+nsNfceRjlUCi13TX23Bh534+nRkC98dk5woVDms9qa TqRo+KmojBZOjBgQl1SFfmd5MtT6cc/MjzLSH+cEVEKwtHhe5Ti1H3hPAYgt7WhE8Nav Tkdi34Sr1U41nWaLcjG4RjfMpoK1QjMzbAAAR9ANSpO8ekAkVvohuM7sk6ulX2H07W43 aFRovYnfjipKQ6Ocw1L8t/vDzGeGYuQ8XsNm618qPAfZTyppryMooCRPl6j1JKrL0Xy3 LwLeI/FEq4Mzn2NXir5Wxa9ITKvnOklalKKlI9nUfXl/5jpf60xEPZQTMXaYazZ2J6qd UdNA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1773339623; x=1773944423; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=dK9k5DTKgk7wxx2+4cg6YZWZrym/c7pdTbONfQY+9AY=; b=qKZZno4Nd2o+XmWIOJNf+0lWHWclNo5cGWuH5QxLjsUq7TY/1TBLQOGdY464UqPTK/ 9UIG0EeK0G+fTpqqGI/r9Li0Lxx+BQnpfLSD0WQYgXYzEQ0n8TfTZzgKyGzVTD0P30R7 VAUhlkjdI8OM6xz1a2pCjAa6RLYbztPKXjtGOY6s1/x58QcS6Xe2VFMmpcHGTnx7N5dq ehqYMAZNo6uRq7emf8agR1qz0z9ZiSptbfVzJ4Xmht41q6jiwq/bU8nLLZ2ZznJ1Na0X 1pL4cWLB74oxgLpIoJxlW5aorvmK9oezFDEnKjZPAksKFIdFU8r8x2Q9HvYnIILRdCQW hs/Q== X-Forwarded-Encrypted: i=1; AJvYcCUazmy+6F4z80ZzjL3CL7WSlz4ejIzDSEnM6FKBOhwdOFWTRvF4yE6sU4pgQ8jBnjjctYDceinA01czKwEX7oxcEj4=@vger.kernel.org X-Gm-Message-State: AOJu0Yw8fh0X0deX1VRfIoM4C7ZnMbbLWxgRrfjqS4jEfM2ShbMoCF8N kfCw+QxWQbQrf6JozbXxU59nqnTnbuQ/EQihDgo96pxywxtvleIh7ilRNvi2K8j7fEcooIyCn3L r7fndN73V9pUrPOOVScHfEw== X-Received: from wmcu23.prod.google.com ([2002:a7b:c057:0:b0:485:385e:a8c1]) (user=vdonnefort job=prod-delivery.src-stubby-dispatcher) by 2002:a05:600d:644a:20b0:485:3bb0:194 with SMTP id 5b1f17b1804b1-48556714b41mr3819805e9.35.1773339622932; Thu, 12 Mar 2026 11:20:22 -0700 (PDT) Date: Thu, 12 Mar 2026 18:20:10 +0000 Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 X-Mailer: git-send-email 2.53.0.851.ga537e3e6e9-goog Message-ID: <20260312182010.111013-1-vdonnefort@google.com> Subject: [PATCH] tracing: Generate undef symbols allowlist for simple_ring_buffer From: Vincent Donnefort To: maz@kernel.org Cc: rostedt@goodmis.org, arnd@arndb.de, nathan@kernel.org, linux-trace-kernel@vger.kernel.org, kvmarm@lists.linux.dev, kernel-team@android.com, Vincent Donnefort Content-Type: text/plain; charset="UTF-8" Compiler and tooling-generated symbols are difficult to maintain across all supported architectures. Make the allowlist more robust by replacing the harcoded list with a mechanism that automatically detects these symbols. This mechanism generates a C function designed to trigger common compiler-inserted symbols. Signed-off-by: Vincent Donnefort diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile index beb15936829d..3b427b76434a 100644 --- a/kernel/trace/Makefile +++ b/kernel/trace/Makefile @@ -136,17 +136,37 @@ obj-$(CONFIG_TRACE_REMOTE_TEST) += remote_test.o # simple_ring_buffer is used by the pKVM hypervisor which does not have access # to all kernel symbols. Fail the build if forbidden symbols are found. # -UNDEFINED_ALLOWLIST := memset alt_cb_patch_nops __x86 __ubsan __asan __kasan __gcov __aeabi_unwind -UNDEFINED_ALLOWLIST += __stack_chk_fail stackleak_track_stack __ref_stack __sanitizer llvm_gcda llvm_gcov -UNDEFINED_ALLOWLIST += .TOC\. __clear_pages_unrolled __memmove copy_page warn_slowpath_fmt -UNDEFINED_ALLOWLIST += ftrace_likely_update __hwasan_load __hwasan_store __hwasan_tag_memory -UNDEFINED_ALLOWLIST += warn_bogus_irq_restore __stack_chk_guard -UNDEFINED_ALLOWLIST := $(addprefix -e , $(UNDEFINED_ALLOWLIST)) +# undefsyms_base generates a set of compiler and tooling-generated symbols that can +# safely be ignored for simple_ring_buffer. +# +$(obj)/undefsyms_base.c: FORCE + $(Q)echo '#include ' > $@ + $(Q)echo '#include ' >> $@ + $(Q)echo 'static char page[PAGE_SIZE] __aligned(PAGE_SIZE);' >> $@ + $(Q)echo 'void undefsyms_base(int n);' >> $@ + $(Q)echo 'void undefsyms_base(int n) {' >> $@ + $(Q)echo ' char buffer[256] = { 0 };' >> $@ + $(Q)echo ' u32 u = 0;' >> $@ + $(Q)echo ' memset((char * volatile)page, 8, PAGE_SIZE);' >> $@ + $(Q)echo ' memset((char * volatile)buffer, 8, sizeof(buffer));' >> $@ + $(Q)echo ' cmpxchg((u32 * volatile)&u, 0, 8);' >> $@ + $(Q)echo ' WARN_ON(n == 0xdeadbeef);' >> $@ + $(Q)echo '}' >> $@ + +clean-files += undefsyms_base.c +targets += undefsyms_base.c + +$(obj)/undefsyms_base.o: $(obj)/undefsyms_base.c + +extra-y += undefsyms_base.o + +UNDEFINED_ALLOWLIST = __asan __gcov __kasan __kcsan __hwasan __sanitizer __tsan __ubsan __x86_indirect_thunk \ + $(shell $(NM) -u $(obj)/undefsyms_base.o 2>/dev/null | awk '{print $$2}') quiet_cmd_check_undefined = NM $< - cmd_check_undefined = test -z "`$(NM) -u $< | grep -v $(UNDEFINED_ALLOWLIST)`" + cmd_check_undefined = test -z "`$(NM) -u $< | grep -v $(addprefix -e ,$(UNDEFINED_ALLOWLIST))`" -$(obj)/%.o.checked: $(obj)/%.o FORCE +$(obj)/%.o.checked: $(obj)/%.o $(obj)/undefsyms_base.o FORCE $(call if_changed,check_undefined) always-$(CONFIG_SIMPLE_RING_BUFFER) += simple_ring_buffer.o.checked base-commit: 33f2e266515717c4b2df585dadefa0525557726c -- 2.53.0.851.ga537e3e6e9-goog