From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-yb1-f180.google.com (mail-yb1-f180.google.com [209.85.219.180]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DFC85450F2; Mon, 28 Jul 2025 14:09:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.219.180 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753711798; cv=none; b=F0MXzcf7OO/YpX302LThu+XPMm7ogrnBJULOhkVgvzOaEC0XawQ1+0+/Z+KeoGmHwVf6DDXRsRYpQb8QeQ239QmaoFz5tjGbO5pJUcEG/KuB0spENHjkzLXyJgdz27sFP2C0O4kq4x/5rgsEn+70lbMHVVjp22h3es7SFnM2zvI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753711798; c=relaxed/simple; bh=NDjCc8R452PUdjbuVaahxAj5XeqbSdHCMwjSCoOTiiw=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=QBca8g0mDEm5ftibh0QL5u34MqW5SB69UGERphjCqGCEjKbwVXa5FV/yvLmTgOddKdIiKkAuLMwDVi4HGh7f993O3DtBxQTXzuqN60bhpDnvDXWclxwUAPVWwAAGFQcBT4PHaAVsSwgjZs8bz85yhpgwPsmzcWhUZjKc/4LD6wY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=iAjRuZ9/; arc=none smtp.client-ip=209.85.219.180 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="iAjRuZ9/" Received: by mail-yb1-f180.google.com with SMTP id 3f1490d57ef6-e8bbb02b887so3816341276.3; Mon, 28 Jul 2025 07:09:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1753711796; x=1754316596; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=3ReXTO4NOQ1zUGOlq4RJ21yg9LAY5yfcMlvjneoaw50=; b=iAjRuZ9/4S7BA+/07Y3mD4G5382TMKrIVj1Qkskmw0OlcPH+1P/WnTZYO7UnmwZve6 rCj6dvhtCQ3iqHyUAaZ8tdGjAocdJG5NfIMoQnmdmPcujmQNeyNDTTIWh2ohTS+ip7em P3tS9FnUHCRyhsyJRWe3hiyRIEuYPJPS5piAImdNNytKw4UW3Sv1D/aGOUwXs3PryRE4 w/30v0KwupJdiXbisLaE7grEM2iPTEbW8a1E2P26g8rLhBPfzM/IrhhLCrDw8y9ya8ZA yal9C+Ke/+O5zdnQUQaMHgv6XIIE3pUfG2itUlJOi9K21PjqapG8nf81je2sJJJyAyVR BBCg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1753711796; x=1754316596; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=3ReXTO4NOQ1zUGOlq4RJ21yg9LAY5yfcMlvjneoaw50=; b=Myy3+dL4bBv4BPfC1C/Z3srGM5/Qs+ScbDDwO8iUWGwS7muCa4dsK1L8CEOuIz2giw O2kbadnQ5CBzdbCF+VKJimmTCQcx+ZjSemxMsy8sR+6fKxXsGRMEC2AAMNsbLSJemgix It/HINMzUFxh1gTQl3+4fpwDM9XEfd+7byanEDdXn/uAZniHYnRHAfvRx0g+OTdaj3wX 9pvTOoqZU6e8I1REQ+JZ7H2LA/PV4pxabqADLEwe5hKUNSuznplg3mkWYFPKMnS6QKus hlShKDM2Zt7FdKPBoVGQyjjr+sQ1zU92yvpqzzTSSv+Q3qL3/aWCAUBVa2qGWy7dO/0/ I3gA== X-Forwarded-Encrypted: i=1; AJvYcCUghurWuZzseJ57JSm4SBfio/tdZCvDpjQA0vOfogMu0qVcQCtRVVAeQbUGt464GCRJx6ho7NfV@vger.kernel.org, AJvYcCWqyxqUhzXwyQZCB6T4vWk7hZcx1BjsemG08Tl4EpKVNQczPuajMUnpLlsrhcvXa1oIDzW/b6EyZAcKfuQ=@vger.kernel.org X-Gm-Message-State: AOJu0Yx08xcEX7mUbmkCYmY37uZNv9SCMgnpE3DNOI/TsIhFXLbfxm/u y8haLLBMI05lBAGwEwI9bZpEfJAEMN3Aw3k/Q6oECoJb25nOuA0bS9wS X-Gm-Gg: ASbGncuTlL6f0YpnTEQjGIsj9L85Jcl+jy4ScLi1JfTNKPK+lbQ396lnp2V5avAHB3A TI4dBAjJpVf0sp506SfHizHEcjY65107/DZdsL1Khg2jSILMyp0/EGcTbnnhQGmuweyDmvOhiMX /inBt2XFFZrlR6/6GNiZQlRJ+BtootUTLW3PpAGH0GrkJsw6Kui8XjCWzuKdsbMpfgVZPwo6Dk+ 0ZkC729kDs7xpVqh7Fp2Y5vNf7xwQypbGgKc5zDHvrgDwJYY7XDkGfSlmkpnMdBl5/HT1Tn0k7U +H6gCX0xGjov7T7dJyWxsUV7tmoJTp8w7a9SqHlZaRM5Q0Xi59jJSzOISBwGpohKGVbWQgi8j8o idCwLMhvBPzoFGUD+tQTnDdzQ/iMTGMbIeb4jKgR0Mg== X-Google-Smtp-Source: AGHT+IEmbcnDjPEVNHVDOcgbY6/zgEo1s/qZUk6+0wtVgdFvPw21hS4A4TmSd1+Eue8XTrBzHOlhvQ== X-Received: by 2002:a05:6902:3401:b0:e8b:79cd:ef1e with SMTP id 3f1490d57ef6-e8df138968fmr12541917276.47.1753711795565; Mon, 28 Jul 2025 07:09:55 -0700 (PDT) Received: from hoboy.vegasvil.org ([2600:1700:2430:6f6f:e2d5:5eff:fea5:802f]) by smtp.gmail.com with ESMTPSA id 3f1490d57ef6-e8df87056ebsm1987427276.40.2025.07.28.07.09.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 28 Jul 2025 07:09:54 -0700 (PDT) Date: Mon, 28 Jul 2025 07:09:51 -0700 From: Richard Cochran To: Jeongjun Park Cc: andrew+netdev@lunn.ch, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, yangbo.lu@nxp.com, vladimir.oltean@nxp.com, anna-maria@linutronix.de, frederic@kernel.org, tglx@linutronix.de, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, syzbot+7cfb66a237c4a5fb22ad@syzkaller.appspotmail.com Subject: Re: [PATCH net v4] ptp: prevent possible ABBA deadlock in ptp_clock_freerun() Message-ID: References: <20250728062649.469882-1-aha310510@gmail.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250728062649.469882-1-aha310510@gmail.com> On Mon, Jul 28, 2025 at 03:26:49PM +0900, Jeongjun Park wrote: > However, when unregistering vclocks in n_vclocks_store(), the locking > ptp->n_vclocks_mux is a physical clock lock, but clk->rwsem of > ptp_clock_unregister() called through device_for_each_child_reverse() > is a virtual clock lock. > > Therefore, clk->rwsem used in CPU0 and clk->rwsem used in CPU1 are > different locks, but in lockdep, a false positive occurs because the > possibility of deadlock is determined through lock-class. > > To solve this, lock subclass annotation must be added to the posix_clock > rwsem of the vclock. > > Reported-by: syzbot+7cfb66a237c4a5fb22ad@syzkaller.appspotmail.com > Closes: https://syzkaller.appspot.com/bug?extid=7cfb66a237c4a5fb22ad > Fixes: 73f37068d540 ("ptp: support ptp physical/virtual clocks conversion") > Signed-off-by: Jeongjun Park Acked-by: Richard Cochran