public inbox for newlib-cvs@sourceware.org help / color / mirror / Atom feed
From: Sebastian Huber <sh@sourceware.org> To: newlib-cvs@sourceware.org Subject: [newlib-cygwin] amd64: prevent KCSan false positives on LAPIC mapping Date: Mon, 26 Oct 2020 13:31:47 +0000 (GMT) [thread overview] Message-ID: <20201026133147.B9031385703B@sourceware.org> (raw) https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=303c61925d9256be02dcbda8f1e5e0d4adf8b3b9 commit 303c61925d9256be02dcbda8f1e5e0d4adf8b3b9 Author: jah <jah@FreeBSD.org> 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. */
reply other threads:[~2020-10-26 13:31 UTC|newest] Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=20201026133147.B9031385703B@sourceware.org \ --to=sh@sourceware.org \ --cc=newlib-cvs@sourceware.org \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).