From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=217.140.110.172 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793112507; b=ymtA7zWGO1gGCRIxwehpLN3a5SoDR4u35RPLSnjS9cIcJsNRtpWFAyA06jVrrxOcAART QQwX4MpqdesWymWC6Zzydb56iwfIcHTz2/nqkQ91s3lgwl0vrwSTrU5WOTVlrcvfD1L71 FkRaGycNFf5crxEEYdXLD3H8TQttTsX08hR0yr6/Zs6HWAdQHiKrNfm90cHLs8qaJ2y7x niu+IXwx4fXUX0sL1QkX/yPcD1yMJAjvpVibjgTU9TUfJAba2uiblzL22sP6wIBnXSiV3 JRvkB6sqE3YwGjMfBAnq16m9+pwnC457u430x+QqUNq5520Cz6qt6G+/pv/hTF2wJww== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793112507; h=DMARC-Filter:Received:Received:DKIM-Signature:Date:From:To:Cc: Subject:Message-ID:References:MIME-Version:Content-Type: Content-Disposition:In-Reply-To; bh=nNSn1iDCXS83Lm/PKK4oFjsXwcuIQQO4gEr+otSMQQw=; b=q813VRqllkbNxyOGNykcZdpVtkA7LdgvCexYUu/NYqnDFaATqgklKZGqPVwfUwLK4VcQ 9MFRg+zCWo7TdGs+3BEw5Ev7Owg1Phm+5yEa7hg+MYKRaCOj/2L45W55AAhcCPygSjIfK SE0gocmfHIPR7NSmPyOBlGxVq1km2W5KCeqYWfetlRBVGQon7pJcRgcX0YZFZXEWH3btg HzhS1e+JXM6252gZCWS9VDhIBjdFXtLXqr9XBXsru1b9gKjCjwkdG/lgq1ikIONe/KezA 5UHAenxttoFhgRPpfpX1wy02+83Kbum5uYGGlFmYq2gXmG1zWh+pfiDGK6dBhbC2Rnw== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass header.d=arm.com header.i=@arm.com header.a=rsa-sha256 header.s=foss header.b=E6pJ45fE; arc=none smtp.remote-ip=217.140.110.172 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 80BAC606A31A; Tue, 27 Oct 2026 14:48:26 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 80BAC606A31A Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=arm.com header.i=@arm.com header.a=rsa-sha256 header.s=foss header.b=E6pJ45fE Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 9733115A1; Tue, 27 Oct 2026 07:48:22 -0700 (PDT) Received: from e129823.arm.com (e129823.arm.com [10.2.213.3]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 265773F7B4; Tue, 27 Oct 2026 07:48:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1793112505; bh=l2aOqIdWdEHxnfTEyx8tR1cJeGMoe3DiGN3Vu5hXhdw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=E6pJ45fEUnYL+9iKScTKSIPvvanwb68q1wHbMVPZKn0aulFKGtBhYDhb7yBEWJ1Ci QQak2KgSS71pttpO/Yy7gbSl6zM/DUr7SlQ7V5tEGhZlrvbfkk7ORAngaeYIZAcEVV zE7iqXTeSnArSbchgZYfP3zvQDTHyn49jDWEy24Y= Date: Tue, 27 Oct 2026 14:48:19 +0000 From: Yeoreum Yun To: Jason Gunthorpe Cc: Jiri Pirko , Yeoreum Yun , linux-coco@lists.linux.dev, linux-kernel@vger.kernel.org, linux-api@vger.kernel.org, x86@kernel.org, kvm@vger.kernel.org, linux-doc@vger.kernel.org, david.quigley@intel.com, lukas@wunner.de, ksinyuk@kernel.org, rodrigo.vivi@intel.com, cedric.xing@intel.com, sameo@meta.com, drdeeglaze@gmail.com, James.Bottomley@hansenpartnership.com, aik@amd.com, jpiotrowski@nvidia.com, qinkun@google.com, pgonda@google.com, jic23@kernel.org, alistair.francis@wdc.com, ankita@nvidia.com, suzuki.poulose@arm.com, kas@kernel.org, rick.p.edgecombe@intel.com, elena.reshetova@intel.com, dave.hansen@linux.intel.com, sathyanarayanan.kuppuswamy@linux.intel.com, peter.fang@intel.com Subject: Re: [PATCH RFC 02/20] ctlv: Add the UAPI wire format and family API Message-ID: References: <20261015145053.3664509-1-jiri@resnulli.us> <20261015145053.3664509-3-jiri@resnulli.us> <20261027141524.GF1685504@ziepe.ca> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261027141524.GF1685504@ziepe.ca> > On Tue, Oct 27, 2026 at 09:02:14AM +0100, Jiri Pirko wrote: > > Mon, Oct 26, 2026 at 07:55:12PM +0100, yeoreum.yun@arm.com wrote: > > >[ 3.856919] ctlv_schema_check_attr+0x3dc/0x538 > > >[ 3.857105] ctlv_schema_check_indexed_nest+0x788/0x958 > > >[ 3.857301] ctlv_schema_validate+0x88/0x180 > > >[ 3.857482] ctlv_msg_test_as_deep_as_the_core_allows+0x11c/0x1e8 > > >[ 3.857698] kunit_try_run_case+0x64/0x188 > > >[ 3.857878] kunit_generic_run_threadfn_adapter+0x30/0x68 > > >[ 3.858086] kthread+0x10c/0x140 > > >[ 3.858245] ret_from_fork+0x10/0x20 > > >[ 3.858398] SMP: stopping secondary CPUs > > >[ 3.858630] Kernel Offset: disabled > > >[ 3.858720] CPU features: 0x0,00000000,00b0802e,9f190bc3,2affe72f > > >[ 3.858872] Memory Limit: none > > >[ 3.858976] ---[ end Kernel panic - not syncing: kernel stack overflow ]--- > > > > > >[...] > > > > > >I think it might be good to configurable according to architecture > > >unless it's not good to reduce the CTLV_MAX_NEST_DEPTH number > > >otherwise, increasing stack size when CTLV is enabled seems unresonable... > > > > Agreed, will lower it down. I think we should be okay with 8 for start. > > I'm surprised this ran out of stack though with even as few as > 32 levels.. Is there accidently something large on the stack? > Nope. When I see the each functions stack allocation: - ctlv_schema_check_indexed_nest(): sub sp, sp, #0xf0 // 240 bytes - ctlv_schema_check_attr(): sub sp, sp, #0xb0 // 176 bytes Roughly (240 + 176) * CTLV_MAX_NEST_DEPTH = 13,952 (around 14KB) consumed. So, I think we need to reduce the depth... -- Sincerely, Yeoreum Yun