From owner-freebsd-bugs@freebsd.org Fri Apr 20 13:08:37 2018 Return-Path: Delivered-To: freebsd-bugs@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id A1129FA1E0E for ; Fri, 20 Apr 2018 13:08:37 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from mailman.ysv.freebsd.org (mailman.ysv.freebsd.org [IPv6:2001:1900:2254:206a::50:5]) by mx1.freebsd.org (Postfix) with ESMTP id 1FA126D7A3 for ; Fri, 20 Apr 2018 13:08:37 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: by mailman.ysv.freebsd.org (Postfix) id C7F80FA1E02; Fri, 20 Apr 2018 13:08:36 +0000 (UTC) Delivered-To: bugs@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id A42DFFA1E01 for ; Fri, 20 Apr 2018 13:08:36 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from mxrelay.ysv.freebsd.org (mxrelay.ysv.freebsd.org [IPv6:2001:1900:2254:206a::19:3]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "mxrelay.ysv.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 26F056D779 for ; Fri, 20 Apr 2018 13:08:36 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org (kenobi.freebsd.org [IPv6:2001:1900:2254:206a::16:76]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mxrelay.ysv.freebsd.org (Postfix) with ESMTPS id 478C52755C for ; Fri, 20 Apr 2018 13:08:35 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org ([127.0.1.118]) by kenobi.freebsd.org (8.15.2/8.15.2) with ESMTP id w3KD8ZJL099023 for ; Fri, 20 Apr 2018 13:08:35 GMT (envelope-from bugzilla-noreply@freebsd.org) Received: (from bugzilla@localhost) by kenobi.freebsd.org (8.15.2/8.15.2/Submit) id w3KD8ZgH099022 for bugs@FreeBSD.org; Fri, 20 Apr 2018 13:08:35 GMT (envelope-from bugzilla-noreply@freebsd.org) X-Authentication-Warning: kenobi.freebsd.org: bugzilla set sender to bugzilla-noreply@freebsd.org using -f From: bugzilla-noreply@freebsd.org To: bugs@FreeBSD.org Subject: [Bug 222027] panic on non-zero RACCT destroy Date: Fri, 20 Apr 2018 13:08:35 +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: CURRENT X-Bugzilla-Keywords: X-Bugzilla-Severity: Affects Only Me X-Bugzilla-Who: commit-hook@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 MIME-Version: 1.0 X-BeenThere: freebsd-bugs@freebsd.org X-Mailman-Version: 2.1.25 Precedence: list List-Id: Bug reports List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 20 Apr 2018 13:08:37 -0000 https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D222027 --- Comment #11 from commit-hook@freebsd.org --- A commit references this bug: Author: avg Date: Fri Apr 20 13:08:05 UTC 2018 New revision: 332816 URL: https://svnweb.freebsd.org/changeset/base/332816 Log: call racct_proc_ucred_changed() under the proc lock The lock is required to ensure that the switch to the new credentials and the transfer of the process's accounting data from the old credentials to the new ones is done atomically. Otherwise, some updates may be applied to the new credentials and then additionally transferred from the old credentials if the updates happen after proc_set_cred() and before racct_proc_ucred_changed(). The problem is especially pronounced for RACCT_RSS because - there is a strict accounting for this resource (it's reclaimable) - it's updated asynchronously by the vm daemon - it's updated by setting an absolute value instead of applying a delta I had to remove a call to rctl_proc_ucred_changed() from racct_proc_ucred_changed() and make all callers of latter call the former as well. The reason is that rctl_proc_ucred_changed, as it is implemented now, cannot be called while holding the proc lock, so the lock is dropped after calling racct_proc_ucred_changed. Additionally, I've added calls to crhold / crfree around the rctl call, because without the proc lock there is no gurantee that the new credentials, owned by the process, will stay stable. That does not eliminate a possibility that the credentials passed to the rctl will get stale. Ideally, rctl_proc_ucred_changed should be able to work under the proc lock. Many thanks to kib for pointing out the above problems. PR: 222027 Discussed with: kib No comment: trasz MFC after: 2 weeks Differential Revision: https://reviews.freebsd.org/D15048 Changes: head/sys/kern/kern_jail.c head/sys/kern/kern_loginclass.c head/sys/kern/kern_prot.c head/sys/kern/kern_racct.c head/sys/kern/kern_rctl.c --=20 You are receiving this mail because: You are the assignee for the bug.=