LKML Archive on
 help / color / Atom feed
From: Dan Rue <>
To: Shuah Khan <>, Ingo Molnar <>,
	Andy Lutomirski <>,
	Dmitry Safonov <>,
	Borislav Petkov <>,,
Subject: selftests/x86/fsgsbase_64 test problem
Date: Fri, 26 Jan 2018 09:36:31 -0600
Message-ID: <20180126153631.ha7yc33fj5uhitjo@xps> (raw)

We've noticed that fsgsbase_64 can fail intermittently with the
following error:

        [RUN]   ARCH_SET_GS(0x0) and clear gs, then schedule to 0x1
                Before schedule, set selector to 0x1
                other thread: ARCH_SET_GS(0x1) -- sel is 0x0
        [FAIL]  GS/BASE changed from 0x1/0x0 to 0x0/0x0

This can be reliably reproduced by running fsgsbase_64 in a loop. i.e.

    for i in $(seq 1 10000); do ./fsgsbase_64 || break; done

This problem isn't new - I've reproduced it on latest mainline and every
release going back to v4.12 (I did not try earlier). This was tested on
a Supermicro board with a Xeon E3-1220 as well as an Intel Nuc with an


             reply index

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-01-26 15:36 Dan Rue [this message]
2018-01-26 16:22 ` Andy Lutomirski
2018-01-26 18:59   ` Andy Lutomirski
2018-01-26 19:46     ` Andy Lutomirski
2018-01-26 22:38       ` Andy Lutomirski
2018-01-26 22:42         ` Andy Lutomirski
2018-01-28 19:21           ` Andy Lutomirski
2018-01-29  9:13             ` H. Peter Anvin
2018-01-29 16:37               ` Andy Lutomirski
2018-01-29 18:12                 ` H. Peter Anvin
2018-01-29 18:26                   ` Andy Lutomirski
2018-01-29 18:30                     ` H. Peter Anvin
2018-02-27 22:59                       ` Dan Rue
2018-01-26 22:56         ` Borislav Petkov
2018-01-28 19:21           ` Andy Lutomirski
2018-01-26 22:51       ` H. Peter Anvin

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:

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20180126153631.ha7yc33fj5uhitjo@xps \ \ \ \ \ \ \ \ \

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

LKML Archive on

Archives are clonable:
	git clone --mirror lkml/git/0.git
	git clone --mirror lkml/git/1.git
	git clone --mirror lkml/git/2.git
	git clone --mirror lkml/git/3.git
	git clone --mirror lkml/git/4.git
	git clone --mirror lkml/git/5.git
	git clone --mirror lkml/git/6.git
	git clone --mirror lkml/git/7.git
	git clone --mirror lkml/git/8.git
	git clone --mirror lkml/git/9.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 lkml lkml/ \
	public-inbox-index lkml

Example config snippet for mirrors

Newsgroup available over NNTP:

AGPL code for this site: git clone