From nobody Wed Jun 29 21:14:03 2022 X-Original-To: bugs@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 2AEA486D656 for ; Wed, 29 Jun 2022 21:14:03 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "R3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4LYDjQ6Nc4z4vY7 for ; Wed, 29 Jun 2022 21:14:02 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org (kenobi.freebsd.org [IPv6:2610:1c1:1:606c::50:1d]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id BB50F1914A for ; Wed, 29 Jun 2022 21:14:02 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org ([127.0.1.5]) by kenobi.freebsd.org (8.15.2/8.15.2) with ESMTP id 25TLE24c046638 for ; Wed, 29 Jun 2022 21:14:02 GMT (envelope-from bugzilla-noreply@freebsd.org) Received: (from www@localhost) by kenobi.freebsd.org (8.15.2/8.15.2/Submit) id 25TLE2cS046637 for bugs@FreeBSD.org; Wed, 29 Jun 2022 21:14:02 GMT (envelope-from bugzilla-noreply@freebsd.org) X-Authentication-Warning: kenobi.freebsd.org: www set sender to bugzilla-noreply@freebsd.org using -f From: bugzilla-noreply@freebsd.org To: bugs@FreeBSD.org Subject: [Bug 264867] kevent EVFILT_TIMER, timer expiration with twice the period Date: Wed, 29 Jun 2022 21:14:03 +0000 X-Bugzilla-Reason: AssignedTo X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: Base System X-Bugzilla-Component: kern X-Bugzilla-Version: 13.1-STABLE X-Bugzilla-Keywords: X-Bugzilla-Severity: Affects Only Me X-Bugzilla-Who: markj@FreeBSD.org X-Bugzilla-Status: Open X-Bugzilla-Resolution: X-Bugzilla-Priority: --- X-Bugzilla-Assigned-To: bugs@FreeBSD.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: https://bugs.freebsd.org/bugzilla/ Auto-Submitted: auto-generated List-Id: Bug reports List-Archive: https://lists.freebsd.org/archives/freebsd-bugs List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-freebsd-bugs@freebsd.org MIME-Version: 1.0 ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1656537242; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=gSbVLt/EcQmmTRP2F7Qa/Qnux/IS2XKkxKR607Z6kYs=; b=HB31tXXGhvKUrvMh+W7ngchoqeSwmFnbKmZYPnJ4NolSv2H79rxCBAPyoXj73wuKnQhMmT L9hpIQZ/YlvdUrAdmrWVtUHdw6Yq75EtL2fcuMQBMvuj0RLxPgJbnzAklejIMgJtr3tdNh NedHe7qLMghPsQAmZBcxGRPuU0YnllfT0mBx0+tGR24OxNNXoa3CS/iyXFYuTg7IbfeGdP TJcmc0VP+yd99IXKiktxW8SPyjA2T6tRCdBU0Yu0maPE0bUerK1dUyRIot6VhGUilxtQ6T pgCeZ+KCeDW5Z0iDQ/dJnbEws8T4lRMkxJfBO4IQoY/Qw7Wq+hfinbj9GeOwGw== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1656537242; a=rsa-sha256; cv=none; b=Z1e6BIoDvVXLmoBLZ7g348V4U0xu+h3/zUPgGWTQGmCHPAfpdYkeV8+5I/alli0g3OwF0o 5MrAHi0HrCFrifbEb3xS80yXrJixjnzCI+u/FqPk1kfBDNOvX01D1X/Fa5THy9fezGtBB5 JwTo43bAleKDHNXy6uG0cK0DwMDPi7/HFFm8El3F/Gj0aI3a2UfdQW2JXS4RSvAf/pqRjA NXK0vuRRmNNzuX4yduMCu1kXqx2D/UFS8J+GUOqspaPyuEv2bK3s+qmzQyqcjN5uRYUFAS EaCobUyHOtlWSR5IP/NUVSXQfoy0QsMupHKbR2KWN/Jkms4Ur5jRYjo6aXixYQ== ARC-Authentication-Results: i=1; mx1.freebsd.org; none X-ThisMailContainsUnwantedMimeParts: N https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D264867 --- Comment #6 from Mark Johnston --- To expand on my question a bit, I think there is a race somewhere in the eventtimer code which occurs when a callout is scheduled on a different CPU= .=20 In particular, when an EVFILT_TIMER event is created, it is "pinned" to the current CPU, and all future callouts will fire on the CPU. I am not sure w= hy kevent does this, it doesn't make much sense to me. If I change filt_timertouch() to set kc->cpuid =3D PCPU_GET(cpuid) each tim= e the event is re-added, then the bug is much harder to trigger. Alternately, if= the test is changed so that each thread pins itself to a different CPU, then the problem is not reproducible for me. (In reply to felice.tufo from comment #4) Does your test module specify the target CPU when arming a callout? --=20 You are receiving this mail because: You are the assignee for the bug.=