From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-176.mta1.migadu.com (out-176.mta1.migadu.com [95.215.58.176]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 051F8270576 for ; Thu, 28 Aug 2025 18:56:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.176 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756407374; cv=none; b=jOJd+kZ91EtoiLIcPtHSkpceg6ozTK4nVVyaOO2L/JU+ehn/6TtrPK4L+GqJiF+iGG/y6E6ajtI10HWuyBC5wY4LTk4BBFMBYdNB5w7M0NDN4hPyVVMgFmleopSLvB7DdbrJNZZD0KLLGREgEp261CKNJkoYIBm7pdaQtCZRUsw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756407374; c=relaxed/simple; bh=o+rWWR9aAIlTHU/zAcgJ18ep0ecbKrZKfu3c9XnHWHI=; h=Content-Type:Message-ID:Date:MIME-Version:Subject:To:Cc: References:From:In-Reply-To; b=LGQoacLEPdHFvCfMnIu92gu0e/65F8cOQWqfJ2/Kkp+7oeUk9hpyeE/zahLhUC2vtnkOolQnBb7F7GnJ0Kq+cGIdDeDxFaWGBeWqjLu7wOWCrPkW216ny3lvcJlqAzGkp2AVy9TahxwQd+jYsAEayTCQx2nOW2/S5ewFg9pHDXs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=wwMroWnT; arc=none smtp.client-ip=95.215.58.176 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="wwMroWnT" Content-Type: multipart/mixed; boundary="------------0a6RtEyOUbqPmlEsckM4giYv" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1756407368; 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: in-reply-to:in-reply-to:references:references; bh=7BgjAKU2pA5MCsElCx1qstMximUD6yAyVfu9WTz2cR8=; b=wwMroWnTz+wgG5FOhD8iDDLAzTHiI5fUTlYrJOc51KcVSjc9tbrxtvxXIgMPqByDwAlwdO 0aGdtPRvkKvjgJzDxUwZgLgUAjkUg+S/7k2LKsqNyGi1tmOKL4YAUbW4aLPom1pGugrnnx GEnYX8FcK4/NbpUqKB+P9lwemM4B9Ro= Message-ID: <8e60d336-9cab-4003-8972-bda0b041d8cf@linux.dev> Date: Thu, 28 Aug 2025 14:56:00 -0400 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: netpoll: raspberrypi [4 5] driver locking woes To: Mike Galbraith , Robert Hancock Cc: Breno Leitao , "netdev@vger.kernel.org" References: <4698029bbe7d7a33edd905a027e3a183ac51ad8a.camel@gmx.de> <39f14032374d5d60c62b283637267a96ce535861.camel@gmx.de> Content-Language: en-US X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Sean Anderson In-Reply-To: <39f14032374d5d60c62b283637267a96ce535861.camel@gmx.de> X-Migadu-Flow: FLOW_OUT This is a multi-part message in MIME format. --------------0a6RtEyOUbqPmlEsckM4giYv Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Hi Mike, On 8/28/25 13:26, Mike Galbraith wrote: > On Thu, 2025-08-28 at 10:57 -0400, Sean Anderson wrote: >> Hi Mike, >> >> On 8/27/25 12:02, Mike Galbraith wrote: >> > Unexpected addendum to done deal datapoint, so off list. >> > >> > On Tue, 2025-08-26 at 11:49 +0200, Mike Galbraith wrote: >> > > >> > > The pi5 gripe fix is equally trivial, but submitting that is pointless >> > > given there's something else amiss in fingered commit. This is all of >> > > the crash info that escapes the box w/wo gripes silenced. >> > > >> > > [ 51.688868] sysrq: Trigger a crash >> > > [ 51.688892] Kernel panic - not syncing: sysrq triggered crash >> > > [ 51.698066] CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.17.0-rc2-v8-lockdep #533 PREEMPTLAZY >> > > [ 51.707234] Hardware name: Raspberry Pi 5 Model B Rev 1.0 (DT) >> > > [ 51.713085] Call trace: >> > > [ 51.715532] show_stack+0x20/0x38 (C) >> > > [ 51.719206] dump_stack_lvl+0x38/0xd0 >> > > [ 51.722878] dump_stack+0x18/0x28 >> > > >> > > That aspect is a punt and run atm (time.. and dash of laziness:). >> > >> > Plan was to end datapoint thread, but after booting pi5's 6.12 kernel, >> > for some reason I fired up netconsole.. and box promptly exhibited the >> > netpoll locking bug warning, indicating presence of 138badbc21a0. >> > Instead of saying to self "nope, just walk away", I poked SysRq-C.. and >> > the bloody damn monitoring box received a 100% complete death rattle. >> > Well bugger. >> >> Did you get a backtrace for this? > > Yes, logs for 6.12.41 and 6.17.0-rc2 attached. > > Since a patch has meanwhile landed, also a log of patched 6.17.0-rc3 > now gripe free (yay) but with aforementioned broken output, followed by > addition of the e6a532185daa revert to confirm it still cures that. > >> And to be clear, the steps to reproduce this are to boot a kernel with >> lockdep enabled with netconsole on macb and then hit sysrq? > > Yup. Looks like the tx completion path can also be called from netpoll. Can you try the attached patch? --Sean --------------0a6RtEyOUbqPmlEsckM4giYv Content-Type: text/x-patch; charset=UTF-8; name="0001-net-macb-Fix-tx_ptr_lock-locking.patch" Content-Disposition: attachment; filename="0001-net-macb-Fix-tx_ptr_lock-locking.patch" Content-Transfer-Encoding: base64 RnJvbSAzZmU0Mzk3NjA5NTUzNzBiOWYwMDVlZjI3MjhiNWZjOWIxNGVlZWE1IE1vbiBTZXAg MTcgMDA6MDA6MDAgMjAwMQpGcm9tOiBTZWFuIEFuZGVyc29uIDxzZWFuLmFuZGVyc29uQGxp bnV4LmRldj4KRGF0ZTogVGh1LCAyOCBBdWcgMjAyNSAxMTo1NTowMSAtMDQwMApTdWJqZWN0 OiBbUEFUQ0ggbmV0IHYyXSBuZXQ6IG1hY2I6IEZpeCB0eF9wdHJfbG9jayBsb2NraW5nCgpt YWNiX3N0YXJ0X3htaXQgY2FuIGJlIGNhbGxlZCB3aXRoIGJvdHRvbS1oYWx2ZXMgZGlzYWJs ZWQgKGUuZy4KdHJhbnNtaXR0aW5nIGZyb20gc29mdGlycXMpIGFzIHdlbGwgYXMgd2l0aCBp bnRlcnJ1cHRzIGRpc2FibGVkICh3aXRoCm5ldHBvbGwpLiBCZWNhdXNlIG9mIHRoaXMsIGFs bCBvdGhlciBmdW5jdGlvbnMgdGFraW5nIHR4X3B0cl9sb2NrIG11c3QKZGlzYWJsZSBJUlFz LCBhbmQgbWFjYl9zdGFydF94bWl0IG11c3Qgb25seSByZS1lbmFibGUgSVJRcyBpZiB0aGV5 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