From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f50.google.com (mail-wm1-f50.google.com [209.85.128.50]) (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 5D8CB410D02 for ; Wed, 29 Apr 2026 19:14:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.50 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777490043; cv=none; b=YhhwE2EQ1yOTBzFgcCHZRj/a5VZzumiUSqo6Zb0yxEFagr3oadBE5mvsorL997JPmcb0QQexB48Cnk0crEiiKkQvp2u15TNhOtUvZGHYznpvEC9W55PoIFLamCjvnEzupZamhWwf0Zbbi+quCr8qiDvtbRvBYoISN15D9FmLLUk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777490043; c=relaxed/simple; bh=Sb5nJTG/Jrr6wKWPpfL/z0Xs/3ZCV3AFhIdRfEM9MGY=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=SdQH03utI4f5Ul+6UrKUJNOyyKPzs6tyk7z0uZeiL0+ZvagoTkTHzKe0LMynGjqak1aLQLbYQRgDVVWFLxz7uzJN+I7wtJxNiYMOzKmlz2WwW7r64vlz8O8UHAhGjLGCKveQ7meQEx/ukXbitYlis/XKD/TRVLdIgor/bRPllAQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=suse.com; spf=pass smtp.mailfrom=suse.com; dkim=pass (2048-bit key) header.d=suse.com header.i=@suse.com header.b=IzQfhmiS; arc=none smtp.client-ip=209.85.128.50 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=suse.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=suse.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=suse.com header.i=@suse.com header.b="IzQfhmiS" Received: by mail-wm1-f50.google.com with SMTP id 5b1f17b1804b1-48a7fe4f40bso1144775e9.0 for ; Wed, 29 Apr 2026 12:14:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=google; t=1777490041; x=1778094841; darn=vger.kernel.org; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=r6Ddd14nNnJPYQ1joj/lUCZz4p3egx61quq7CAtkrps=; b=IzQfhmiSlTeKS+M0MBA5O6uFDeTF+vBB6J/3RHtOxjj47EWvjhHh2Sj3pOXJc9tny/ RmrwLRqbZ2XMhueg+iF+Xl5tffBl6OHR3G6ZT+8ntkvbtHR6ilTYEgb7CjehKdyTBD4l Gt36FwtFVkHyZCFEw/7YujCW2NnjLRQqee7zDsaptYf4oO6ncRngOrAnLkheitsN4wE1 786yLIbriIX5qCg6t4bbXfZq14f2yj8mLEEuE3Dz6upahtlai+LXJbdu1cPTEaU6yDp2 QYtCOn4yZwx7sELMx/E9D6musdLAbfKSBF+si7e7hLqSfDt5L4vxw7XUfCmnPHIsCs1L I75g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1777490041; x=1778094841; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :x-gm-gg:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=r6Ddd14nNnJPYQ1joj/lUCZz4p3egx61quq7CAtkrps=; b=di7HpQ0IwEabfWeQXyObPJIRLcvWQJ/oXkplhmFABjJG/XkguzN/h1j9K4cYJ2/5y/ cu3pzcjODlv2Ot+3+FNe2QFBtLp7FWeBjCajegXjhCPRl1lhP+s1xNJXVRulLRr/tQOH T6EzJLeaBG9zuB2k20pFMitYP7e0klX54p/x8/LClzbxAmWNyvYwqQJXV8U2NTSEITPw aCprPhS09+6CPqBSP4PtCBIdFzBM6j10teCknT677Y5mrHiTFzUUzJSJqAGt4NjYpXhy mIEWMdLq7ICOXIEms0j1h7XbJQC50RMGvGC4NHC9J0SvH6olSyEHGkihAf7wZKzs+CiX Wd1w== X-Gm-Message-State: AOJu0Yxz/xzFgab1GJKKHata5wZuLBE9JPR6zf0Ke1K2zJoep/wTab6l EnJMpgQhFHbiEEOABEkq/9QjYFNs3rflZyfynozJCgGMjjipfA8hc0OrdmINRA9vtLI= X-Gm-Gg: AeBDietrX2424hIe45iyFw1eQYO6+mKu/DewAg5oae3rjqf7ZNmIA4HJtUC34zwVx1I A+309keR5VlCzXT1FnnlgQrgg16RrVKQas6xDNU07TPGBR9bGGK4ID/rmCjx+qYMplCbvAGhHB9 jjGdTANH3126NyhDiZjyOrjWLo38UmSbppwF+fFdzADFlgy9vSscNmWqc5eYz7HxiyvnBEVmNdW sh0NEtw05tvQZjbq4o6zeFkYRL76esaa+4gP+dkKF47uZSdjzKV6A/YJL/lRHywahO/cghVJhMT sqItsv9LinubJ8D6uzEmd2s5rNVZsNBIaW9AXgD3bKu53lrCppHTrCDKJ1XeBRI2JzVAbUIauz8 cuvvHeKU00tasYwMyY/LCCX3LHfgDee5tOrkgFmRo3A07sVsgy+nBpvveqz9CxhJrnSF/93u6VT VEuj9EtFoKrSLGR/Uyxm+GKuhTPONMZIQscK9Ul6Hrbt9Tk0/J+UkKX3svzwzyOy/ksc0Zl7zat zcVkHJm+/TxugWT X-Received: by 2002:a05:600c:8595:b0:489:6c22:e081 with SMTP id 5b1f17b1804b1-48a7b4d5292mr62591585e9.0.1777490040610; Wed, 29 Apr 2026 12:14:00 -0700 (PDT) Received: from ?IPV6:2001:a61:13a6:c701:bf3c:e2f0:87b2:c525? ([2001:a61:13a6:c701:bf3c:e2f0:87b2:c525]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-48a7c305371sm24363565e9.18.2026.04.29.12.14.00 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 29 Apr 2026 12:14:00 -0700 (PDT) Message-ID: Date: Wed, 29 Apr 2026 21:13:59 +0200 Precedence: bulk X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] usb: core: hcd: fix possible deadlock in rh control transfers To: Alan Stern , Oliver Neukum Cc: linux-usb@vger.kernel.org, tiwai@suse.com References: <69ec231a.a00a0220.7773.000c.GAE@google.com> <20260429104209.19620-1-oneukum@suse.com> Content-Language: en-US From: Oliver Neukum In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 29.04.26 21:04, Alan Stern wrote: > Besides, even if a resume was necessary, wouldn't the same VM magic that > works for the reset thread also work for the resume? After all, they They need not be the same thread. That is the point. usb_reset_device() does a resume. However, it is possible for this to race with another thread doing a resume or a suspend. In that case it will block and wait for another thread. Hence we essentially get priority inversion more or less. Regards Oliver