From nobody Sat Sep 25 16:43:35 2021 X-Original-To: net@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 090BF17D144D for ; Sat, 25 Sep 2021 16:43:37 +0000 (UTC) (envelope-from avg@FreeBSD.org) Received: from smtp.freebsd.org (smtp.freebsd.org [IPv6:2610:1c1:1:606c::24b:4]) (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 "smtp.freebsd.org", Issuer "R3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4HGvqD6vnJz4q7h; Sat, 25 Sep 2021 16:43:36 +0000 (UTC) (envelope-from avg@FreeBSD.org) Received: from [192.168.0.88] (unknown [195.64.148.76]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client did not present a certificate) (Authenticated sender: avg/mail) by smtp.freebsd.org (Postfix) with ESMTPSA id 5C51DCA61; Sat, 25 Sep 2021 16:43:36 +0000 (UTC) (envelope-from avg@FreeBSD.org) Subject: Re: page fault in pfioctl From: Andriy Gapon To: Kristof Provost Cc: net@freebsd.org, Konstantin Belousov References: <980E0B5C-41CF-466E-AD45-7B93532199F4@freebsd.org> Message-ID: <25ec0404-4fc8-c8c5-3916-20c8e094aa62@FreeBSD.org> Date: Sat, 25 Sep 2021 19:43:35 +0300 User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:78.0) Gecko/20100101 Firefox/78.0 Thunderbird/78.14.0 List-Id: Networking and TCP/IP with FreeBSD List-Archive: https://lists.freebsd.org/archives/freebsd-net List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-freebsd-net@freebsd.org MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-ThisMailContainsUnwantedMimeParts: N On 25/09/2021 19:38, Andriy Gapon wrote: > On 25/09/2021 19:34, Kristof Provost wrote: >> On 25 Sep 2021, at 18:25, Andriy Gapon wrote: >>> On 13/06/2021 11:19, Kristof Provost wrote: >>>> On 13 Jun 2021, at 09:41, Andriy Gapon wrote: >>>>> Based on >>>>> the panic message (page fault with non-sleepable locks held), it seems that >>>>> the problem is with holding the lock across the copyout.  Usually that >>>>> won't panic, but if the destination happens to be paged out... And only >>>>> with INVARIANTS, I guess... >>>> >>>> Oh right. Thanks. I’ve gotten bitten by that one before, but had clearly >>>> garbage collected the memory. >>>> >>>> I’ll fix this one and check for others on Monday. >>>> >>>> I’ll also see of we can persuade copyout to always panic on this bug, not >>>> just when the destination memory is actually paged out. That way we’ll catch >>>> this in the regression tests in the future. >>> >>> I upgraded to the latest stable/13 and hit a fresh panic of the same type. >>> This time it's in pf_getstatus() and it's a copyout while 'pf rulesets' lock >>> is held. >>> >> I believe that’s fixed by >> https://cgit.freebsd.org/src/commit/sys/netpfil/pf/pf_ioctl.c?id=cb13059663e455b3fc69c293dadec53c164490dc >> > > Thank you for the pointer! > I believe it should help with the witness warning. > Still not sure what's going on with copyout_nosmap_std(). > Ah, sorry for the noise, trap_fatal() is exactly because the witness did not like the fault. -- Andriy Gapon