From nobody Fri Apr 21 08:53:31 2023 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 4Q2pGM3qGrz467M1 for ; Fri, 21 Apr 2023 08:53:31 +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 4Q2pGM1Bbbz4ZhN for ; Fri, 21 Apr 2023 08:53:31 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1682067211; 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; bh=BvUYOQBVy0IJyBHXBOOdqaI2i12bu5PkUcEJpYv66gE=; b=TmYsXKARzfV0k3gWkF9KlQnXySRIiAU+hcq3MXdSX+hkl8qdEeAlbwagP7pSbP+bsFSsPK Y5hKCJ17LLV4L4PMg36N3tDxYo1756EswnEqaWBcLsz+qWlGSlncqqpstO1zu3So81zMUD neb73kkITzamNWSOf0FolInStM4ybVGfjDN786SNU5dQ0tgFVw+wqOmSfxLB3/uCb9ADHk fy0ekKGba5ZeQkTa4yw5hiRSw68Ih4p7xNt5f+sQbpLyJPWcJA5UQkI8CCO0Ysppk9iJaD aZkk7tgjCIW85fsBTK+rXd9TDqOzLNBmV24V5d0hKyk/IgSFSQlDlkJ5a3mR0g== ARC-Authentication-Results: i=1; mx1.freebsd.org; none ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1682067211; a=rsa-sha256; cv=none; b=N/70hgjjPryEjDO4vcQhbcps3EybzC/lqf/bnwIL3lVU6avxAYDnXvVG0+qb99G8WDZ4Vw YFTCfx5lILjKvUj58SKKR0Pxz3UA+5VL5datDvA+qbMmTPxDL4ZDQC5PMxcK0txBon8Auh nANgiIVCCPCQflUmLs2NRwWS2amF9dYvegpzX3jkjqvJIlBmy2RB+sU1e3NjJZW2/G/Qhf JsneeKigatPUwOL3l204vp2XvVurJpejGL4H095H1MizvpLsSsdResybuNturs4FEEE7nk ARTDiw4xOBVEHenZsMQqRBGOnjit0H0fvvt/k0DVKMobY9VxwIB2Uh+GKiv5KQ== 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 4Q2pGM0JNvzF2f for ; Fri, 21 Apr 2023 08:53:31 +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 33L8rUea099834 for ; Fri, 21 Apr 2023 08:53:30 GMT (envelope-from bugzilla-noreply@freebsd.org) Received: (from www@localhost) by kenobi.freebsd.org (8.15.2/8.15.2/Submit) id 33L8rUfm099833 for bugs@FreeBSD.org; Fri, 21 Apr 2023 08:53:30 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 270975] [hang] system hangs with heavy io and regular syncing Date: Fri, 21 Apr 2023 08:53:31 +0000 X-Bugzilla-Reason: AssignedTo X-Bugzilla-Type: new X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: Base System X-Bugzilla-Component: kern X-Bugzilla-Version: 12.4-RELEASE X-Bugzilla-Keywords: X-Bugzilla-Severity: Affects Some People X-Bugzilla-Who: nkoch@demig.de X-Bugzilla-Status: New X-Bugzilla-Resolution: X-Bugzilla-Priority: --- X-Bugzilla-Assigned-To: bugs@FreeBSD.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: bug_id short_desc product version rep_platform op_sys bug_status bug_severity priority component assigned_to reporter Message-ID: 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 X-ThisMailContainsUnwantedMimeParts: N https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D270975 Bug ID: 270975 Summary: [hang] system hangs with heavy io and regular syncing Product: Base System Version: 12.4-RELEASE Hardware: i386 OS: Any Status: New Severity: Affects Some People Priority: --- Component: kern Assignee: bugs@FreeBSD.org Reporter: nkoch@demig.de We are running an embedded system with processes partly at rtprio doing io = and often syncing. We have there a 12.1-p13 kernel with some modifications, including special device drivers, e.g. an sram based disk device. As we rarely found the system to be completely unresponsive (no login, ssh possible) I added a utility that runs at very high rtprio and monitors the other processes. If it sees 100% cpu it throttles those processes using SIGSTOP/SIGCONT. That helped me to see that there was a thread in unkillable sleep in syscall sync using up most of the cpu, like it was busy waiting for something. After that I did some testing with unmodified kernels (withoud my device drivers) and simple test scripts that do write+sync+random sleep at normal and realtime priority. So far I've tested FreeBSD12.1-release, FreeBSD12.1-p13, FreeBSD12.4-releas= e. I've managed to have all of them bein unresponsive after one or more hours. For FreeBSD12.4, I've had one console running a shell with rtprio. After "killall sync &" and "killall sh & " the system was hanging. I could only switch vtys but could = not login. In an other test I've got the hang by calling "procstat kstack 1" in the rt= prio shell. One detail: kern.dirdelay, kern.metadelay and kern.filedelay are all set to= 1. --=20 You are receiving this mail because: You are the assignee for the bug.=