From nobody Tue Jan 11 07:28:27 2022 X-Original-To: freebsd-hackers@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 219AD1930A2F for ; Tue, 11 Jan 2022 07:28:31 +0000 (UTC) (envelope-from avg@FreeBSD.org) Received: from smtp.freebsd.org (smtp.freebsd.org [96.47.72.83]) (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 4JY2Nv0Xmvz3l77; Tue, 11 Jan 2022 07:28:31 +0000 (UTC) (envelope-from avg@FreeBSD.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1641886111; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=FdZfQo3ngx/hA4yS21aYQ3cd8xnUTGPunJwJHvbX9R8=; b=P9xG/ObL6kvrMDEqXX58wuCDWkGXHWqT2mIPO0GcSDODsdukVZDedJS/d0LE212NyxKLTR 8um+j461/MeWFF5m8Eb+k5/0J3X3AqFndJDngtvL25PXewyNQcQOm2DWJ3Va86ffyGZbP9 iAEnOL+vEAJJE1PKeEkfFcwoDp19znsN70t0wWJxrtLAq0l7W2aiNdWkxsaHgbPIAMvY9L e1a0QWXnPljpT3i4tKXfwMwpNKCJKcYDSJ35y7LHeRGelfr9pqxadbRwPV5UFVcwY3MA7m T/P2ZxxZx2jyIO8gNlZOBj6zxeM16Lf4LOjBwJbrWvmy3M1tC0zLyaIh5FJoIQ== 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 6FD001E39; Tue, 11 Jan 2022 07:28:30 +0000 (UTC) (envelope-from avg@FreeBSD.org) Message-ID: <1bf39343-c9b2-353c-63e7-8604adc9d391@FreeBSD.org> Date: Tue, 11 Jan 2022 09:28:27 +0200 List-Id: Technical discussions relating to FreeBSD List-Archive: https://lists.freebsd.org/archives/freebsd-hackers List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-freebsd-hackers@freebsd.org MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:91.0) Gecko/20100101 Firefox/91.0 Thunderbird/91.4.1 Subject: Re: Debugging a (potentially?) ZFS-related panic, and discussion about large patchsets Content-Language: en-US To: Mateusz Guzik , Mark Johnston Cc: freebsd-hackers@freebsd.org References: <20220110221116.gustgfgfge6pb5fe@mutt-hbsd> From: Andriy Gapon In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1641886111; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=FdZfQo3ngx/hA4yS21aYQ3cd8xnUTGPunJwJHvbX9R8=; b=NweP1lztloNqQE75HHy+FIyqUK6PL2Ff87eOc3ZKpgytUXgXUszeUs8Du7cwHUdBtcBs38 3sDJ8eeC/lHPRK5XqV63HmMpTQXE8Vhz23ZEjE5DX0+8jsGAtyVCszam0lNKQj/84r3s6G xo3PUZHiLQ5IMDwP/Stbk7FGxczz1/CShDHxEt/ZS2/fLNMzhNN5uxtX+gQ0NGn8srKXZS 5K9nPDGKPSPE7MLRQFkNfOnelzfCmk00lAmn3z2cC0wn21mX3ot/KYHSk/enS1NxaPU/Av 3Y+/gx9U5U/HqECU4xNZgBveo+eBJt4Q3JZfEr3y5J6HS1D+dpduBziNtNQggw== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1641886111; a=rsa-sha256; cv=none; b=elKR2YD15oDdN0Kx5mt9GQOmnEgOEGjM5Wr77xfLO7erpdAIafrT2oRfyvN2fhFX8rrtRr 9b9+K2dsCFiNba0jO/QOlGOyMTkEc+p+rVxK99Y89TN9b9qE+92rfMqLSpXznf5ab0G9af ohBZrrmmORpGiGKYSOSvgb02m+Kmky2iwztR1jsCeHTxuJqfKfivQtCAB1dkc43X5hzBps uWkLgTW3iQOyOdrFfGm09tEB7wYQTKCNk3bRKmwNX8Au/ytjBOPZZmfMHvj1YPD6vTcPfk Z2c8PiIMIFWOEDFK20hh4iMLABgxAz4CKJXtsiqqBAMFi578n8YHV0+LS4uXPg== ARC-Authentication-Results: i=1; mx1.freebsd.org; none X-ThisMailContainsUnwantedMimeParts: N On 11/01/2022 01:43, Mateusz Guzik wrote: > imo the kernel should be patched to obtain the trace on its own. As > the target has interrupts disabled it will have to do it with NMI, but > support for that got scrapped in > > commit 1c29da02798d968eb874b86221333a56393a94c3 > Author: Mark Johnston > Date: Fri Jan 31 15:43:33 2020 +0000 > > Reimplement stack capture of running threads on i386 and amd64. This is an off-topic for the thread, but as far as I recall, even when the stack capture (e.g., for procstat -k) was implemented using NMI there was a piece of code in the corresponding NMI handler that skipped the stack tracing if interrupts were disabled. I don't recall / know why. You can see that in the removed stack_nmi_handler() that used to be in sys/x86/x86/stack_machdep.c. -- Andriy Gapon