From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 1921) id B9031385703B; Mon, 26 Oct 2020 13:31:47 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org B9031385703B Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit From: Sebastian Huber To: newlib-cvs@sourceware.org Subject: [newlib-cygwin] amd64: prevent KCSan false positives on LAPIC mapping X-Act-Checkin: newlib-cygwin X-Git-Author: jah X-Git-Refname: refs/heads/master X-Git-Oldrev: 47efca5ac3da9aacc3a4216a1725ed2d62dd27b1 X-Git-Newrev: 303c61925d9256be02dcbda8f1e5e0d4adf8b3b9 Message-Id: <20201026133147.B9031385703B@sourceware.org> Date: Mon, 26 Oct 2020 13:31:47 +0000 (GMT) X-BeenThere: newlib-cvs@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Newlib GIT logs List-Unsubscribe: , List-Archive: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 26 Oct 2020 13:31:47 -0000 https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=303c61925d9256be02dcbda8f1e5e0d4adf8b3b9 commit 303c61925d9256be02dcbda8f1e5e0d4adf8b3b9 Author: jah Date: Sat Sep 12 07:04:00 2020 +0000 amd64: prevent KCSan false positives on LAPIC mapping For configurations without x2APIC support (guests, older hardware), the global LAPIC MMIO mapping will trigger false-positive KCSan reports as it will appear that multiple CPUs are concurrently reading and writing the same address. This isn't actually true, as the underlying physical access will be performed on the local CPU's APIC. Additionally, because LAPIC access can happen during event timer configuration, the resulting KCSan printf can produce a panic due to attempted recursion on event timer resources. Add a __nosanitizethread preprocessor define to prevent the compiler from inserting TSan hooks, and apply it to the x86 LAPIC accessors. PR: 249149 Reported by: gbe Reviewed by: andrew, kib Tested by: gbe Differential Revision: https://reviews.freebsd.org/D26354 Diff: --- newlib/libc/include/sys/cdefs.h | 2 ++ 1 file changed, 2 insertions(+) diff --git a/newlib/libc/include/sys/cdefs.h b/newlib/libc/include/sys/cdefs.h index 1be994ffd..da7290921 100644 --- a/newlib/libc/include/sys/cdefs.h +++ b/newlib/libc/include/sys/cdefs.h @@ -716,8 +716,10 @@ */ #if __has_attribute(no_sanitize) && defined(__clang__) #define __nosanitizeaddress __attribute__((no_sanitize("address"))) +#define __nosanitizethread __attribute__((no_sanitize("thread"))) #else #define __nosanitizeaddress +#define __nosanitizethread #endif /* Guard variables and structure members by lock. */