From owner-freebsd-bugs@freebsd.org Tue May 21 08:56:32 2019 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 DD73715A776A for ; Tue, 21 May 2019 08:56:31 +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 6D9E78491E for ; Tue, 21 May 2019 08:56:31 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: by mailman.ysv.freebsd.org (Postfix) id 2B3AE15A7768; Tue, 21 May 2019 08:56:31 +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 03DBB15A775B for ; Tue, 21 May 2019 08:56:31 +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 TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) server-signature RSA-PSS (4096 bits) client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.ysv.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 84F0484917 for ; Tue, 21 May 2019 08:56:30 +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 BBB0BD901 for ; Tue, 21 May 2019 08:56:29 +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 x4L8uT9W022753 for ; Tue, 21 May 2019 08:56:29 GMT (envelope-from bugzilla-noreply@freebsd.org) Received: (from www@localhost) by kenobi.freebsd.org (8.15.2/8.15.2/Submit) id x4L8uTIc022752 for bugs@FreeBSD.org; Tue, 21 May 2019 08:56:29 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 238017] crash in dummynet, drain_scheduler_cb, si->sched == NULL Date: Tue, 21 May 2019 08:56:29 +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: CURRENT X-Bugzilla-Keywords: X-Bugzilla-Severity: Affects Only Me X-Bugzilla-Who: avg@FreeBSD.org 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 MIME-Version: 1.0 X-BeenThere: freebsd-bugs@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Bug reports List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 21 May 2019 08:56:32 -0000 https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D238017 Bug ID: 238017 Summary: crash in dummynet, drain_scheduler_cb, si->sched =3D=3D NULL Product: Base System Version: CURRENT Hardware: Any OS: Any Status: New Severity: Affects Only Me Priority: --- Component: kern Assignee: bugs@FreeBSD.org Reporter: avg@FreeBSD.org Unfortunately, all we have is some information from a ddb text dump. We do= not have a vmcore and we do not have a way to re-create the crash. It happened just once on a production system. So, the information follows. dn_enqueue fs 0 si 0, dropping Fatal trap 12: page fault while in kernel mode cpuid =3D 0; apic id =3D 00 fault virtual address =3D 0x60 fault code =3D supervisor read data, page not present instruction pointer =3D 0x20:0xffffffff8077bdff stack pointer =3D 0x28:0xfffffe1096343910 frame pointer =3D 0x28:0xfffffe1096343920 code segment =3D base 0x0, limit 0xfffff, type 0x1b =3D DPL 0, pres 1, long 1, def32 0, gran 1 processor eflags =3D interrupt enabled, resume, IOPL =3D 0 current process =3D 0 (dummynet) db:3:psinfo> bt Tracing pid 0 tid 100248 td 0xfffff8002829d4d0 stack1 drain_scheduler_cb+0x1f drain_scheduler_sch_cb+0x25 dn_ht_scan_bucket+0x7a dn_drain_scheduler+0x20 dummynet_task+0x219 taskqueue_run_locked+0x71 taskqueue_thread_loop+0x56 fork_exit+0x121 fork_trampoline+0xe drain_scheduler_cb+0x1f: movq 0x60(%rdx),%rax Here is disassembly of the function with some notes of mine: 0xffffffff8077bde0 <+0>: push %rbp 0xffffffff8077bde1 <+1>: testb $0x20,0x90(%rdi) // test DN_ACTIVE 0xffffffff8077bde8 <+8>: mov %rsp,%rbp 0xffffffff8077bdeb <+11>: jne 0xffffffff8077bdf4 0xffffffff8077bded <+13>: cmpq $0x0,0x78(%rdi) 0xffffffff8077bdf2 <+18>: je 0xffffffff8077bdf8 0xffffffff8077bdf4 <+20>: leaveq 0xffffffff8077bdf5 <+21>: xor %eax,%eax 0xffffffff8077bdf7 <+23>: retq 0xffffffff8077bdf8 <+24>: mov 0x88(%rdi),%rdx // rdx =3D si->sched 0xffffffff8077bdff <+31>: mov 0x60(%rdx),%rax // rax =3D si->sched= ->fp 0xffffffff8077be03 <+35>: testb $0x1,0x10(%rax) So, it seems that dummynet ran into dn_sch_inst with sched field being NULL. I am not sure how that could be possible. Also, I am not sure if that "dn_enqueue ..." message is related to the cras= h. I found a somewhat similar but different and very old report: bug 166937. It seems that it was not really root-caused and fixed, but marked as fixed because of a chance that it could have been caused by flaky hardware. --=20 You are receiving this mail because: You are the assignee for the bug.=