From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=74.208.142.49 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794479792; b=izoAIjRmkCcEqttswhmB8t861Kd5TosDWJRzwkaFJnaIvbi7cZQlVOi2bpvP5iJQSqGw K+jaKh2fTdJt6b3TA+xA8GHplyPcLuioCTWPGkp7/U5HrDE6bzqOpSjx4KDQx1M+UnxSJ It+F0jnRfsQnDYpM4mXit+x7WkQyhkXTfZXfomtrewI1L0VCN1FB5H83J3o4m6IZnzsf2 lxRSWu+9BuSVicJz4W4cuWtMdz0jgJ47ssyv3jzvsjV7pLxlax88oXhWs+vtB6TH9YLMC cDiCUzczurxuhLG83cuzbUtsMWLGI4rRAAMH/Iz5cLbt2Vi2KBUjEw8R0yuMGvkmC3w== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794479792; h=DMARC-Filter:DKIM-Signature:Received:From:To:Cc:Subject:Date: Message-ID:X-Mailer:In-Reply-To:References:MIME-Version: Content-Transfer-Encoding; bh=AazEAsk7AgRZJ/1X0wf0AnTfGLKx3ePR+szUy82to1M=; b=mgZWHHlAqbz9mtN+WQZOcfs9lQolImKeVRBk76P3ImtcPuorQ/XQzh86T5oY87s6CxuO abaA0p1EoOHRKkvvEA+LDhN3vB22lL5YsXANK3XMLkDpU5rDCZTf0JMomf/zNriX+YBWJ eCeBA0UTn/gz+8By+UxmN41S8K3S6XyZsi7Dru9oK3C3WltarVm2VGWpTmoCTEux6w8bW fOQqpljvrDpHYOd5TXR6/kedm6h9ZhMjAjq3RW2/yvpyJ/Gfhy3wsMA8w4eBP8PQqbwba We54Wd55J1C8Ho9SQ9SZOaOl9RiqzIaWwW3mkJB+LyrGqIXojz7UKCPEMxaQmP7Iqjg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=kernelriot.com; spf=pass smtp.mailfrom=kernelriot.com; dkim=pass header.d=kernelriot.com header.i=@kernelriot.com header.a=rsa-sha256 header.s=kr2026 header.b=JigvEjAJ; arc=none smtp.remote-ip=74.208.142.49 Received: from mail.kernelriot.com (mail.kernelriot.com [74.208.142.49]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 10B85606A887; Thu, 12 Nov 2026 10:36:31 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 10B85606A887 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=kernelriot.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=kernelriot.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernelriot.com header.i=@kernelriot.com header.a=rsa-sha256 header.s=kr2026 header.b=JigvEjAJ DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernelriot.com; s=kr2026; t=1794479791; bh=8R17N+nl0pxoL/AYQkf0ULWjSnupGqKL3Jsa9AysHI8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Transfer-Encoding:From; b=JigvEjAJLRaovI4O4d9Slq4P7kjtV8g6cn2D7p+8a3jfMrqt6f6jvNYrb2GtpMdJ9 w8GGjwqqmqSmEx2obPC48sCrciFdlEY4R+au73jjUGELIgyr1QIePQ1cy2WYEtrb5q SOl4GAjssrXPgoB8EuDsucXYeg6R7oyXd5em0GxQ6iC4gYdW/WgIHXlhoqI8kq+Rsg xjtqntnKOxqkF/y5zF2jN1cTRSTWPvW9QZs0FMkwkh72k+eCQOGADursHy1c/qAgs2 MIt+qxwMjGzoYASZdO2LKleBAY8rQEue+C/pQv/gaAZpOxcq/b0LLxmlo7thRP+K0C qr89ahL00oQ3g== Received: by mail.kernelriot.com (Postfix, from userid 995) id 1360381A15; Thu, 12 Nov 2026 10:36:31 +0000 (UTC) From: Magnus Leatti To: syzbot+9ef743bba3a17c756174@syzkaller.appspotmail.com Cc: syzkaller-bugs@googlegroups.com, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, oe-linux-nfc@lists.linux.dev, David Heidelberg , Johannes Berg , Deepanshu Kartikey Subject: Re: [syzbot] INFO: task hung in rfkill_sync_work Date: Thu, 12 Nov 2026 07:36:01 -0300 Message-ID: <20261112103601.1848657-1-magnusleatti@kernelriot.com> X-Mailer: git-send-email 2.56.0 In-Reply-To: <000000000000788a6905f0c06160@google.com> References: <000000000000788a6905f0c06160@google.com> 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-Transfer-Encoding: 8bit Hi, This looks like the device_lock vs rfkill_global_mutex inversion fixed by 1ab526d97a57 ("net: nfc: fix deadlock between nfc_unregister_device and rfkill_fop_write"). That fix credited a different syzbot report, so this one was never linked to it. The report shows one task holding rfkill_global_mutex in rfkill_fop_write and waiting for the NFC device lock in nfc_dev_down, while another holds that device lock in nfc_unregister_device and waits in rfkill_unregister. rfkill_sync_work is stuck behind them. The C reproducer, 600 s per kernel, x86_64 under QEMU/KVM: 1ab526d97a57^ hung task report at 60 s 1ab526d97a57 no hang 9d66f26fefac no hang (mainline) #syz fix: net: nfc: fix deadlock between nfc_unregister_device and rfkill_fop_write Thanks, Magnus