From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 E42251F4285 for ; Tue, 1 Jul 2025 17:50:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751392234; cv=none; b=Ghj9w5nxgJs5AIoA0uQtHSwfnuKoTITPs/7TtVlJKiPUIRv9Udg5lLvylBFyY7vuf9NkEqo+jXS9NEUxhEnon8mzgiBM2e87VjwJ9gNE8bHVzzJfSLO/MXBI7j4z73qjVwiLQl8CvEEAnB6LIl8lq6dmLbA4S5vKGcv5rWBRkhE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751392234; c=relaxed/simple; bh=b0rjoau6A7re4Bat0GuA+Hj69HUgYYxDJokL+1r1gTw=; h=From:To:Subject:Date:Message-ID:In-Reply-To:References: Content-Type:MIME-Version; b=sGElg6xFWP5YN45Z+26K6QU0wXuvMI8bu0ayF4VyOjpPiwJ7lpP3WJ6RgJI4ogtEQYcUqHEM/sZKweH94PsiwaYJijd/nDhuHl0tOP6pix0xlYbamrn3DBV48CbYQOte4GxNWk2O4LUdeb4qtCPQlEAFlUS/NO93sqmIADxx5fA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=u60QW2ve; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="u60QW2ve" Received: by smtp.kernel.org (Postfix) with ESMTPS id 6CA0AC4CEEF for ; Tue, 1 Jul 2025 17:50:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1751392233; bh=b0rjoau6A7re4Bat0GuA+Hj69HUgYYxDJokL+1r1gTw=; h=From:To:Subject:Date:In-Reply-To:References:From; b=u60QW2venD9cqdCGvYtTKtiY9m0rsDtAkF9SZGQK6wH/1TLyh6EYvC3jsc7BXCbTi U7S/Z24RI7X5hvetDesGBkVl+oU3I9Yo/Dv+GaeCVD8PBP5MgsHw2PNF0ys9eXu7TX RERWdATtR2XaXk3hL5e9gHKyioKGMFIZOOQc2IOBLO16XaiwvRxUYsymMqdp60Nms7 lq9XyZkjgTUDdIgyxn/bO+S3aNOqfuhjI46hnvalId+a2qB1dRGQ7+8lBhqGIQyEZh +sRdUNtA8saOB6AF0soSGE9+MAT+CAxmYdUR4roF+MA8Ed/1RiFwK1lOHTlaEElgo7 mGmC1Cyq85mQQ== Received: by aws-us-west-2-korg-bugzilla-1.web.codeaurora.org (Postfix, from userid 48) id 5FD0BC41613; Tue, 1 Jul 2025 17:50:33 +0000 (UTC) From: bugzilla-daemon@kernel.org To: linux-usb@vger.kernel.org Subject: [Bug 220272] Latent race condition in USB code unveiled with optimized memset_64.S Date: Tue, 01 Jul 2025 17:50:33 +0000 X-Bugzilla-Reason: None X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: AssignedTo drivers_usb@kernel-bugs.kernel.org X-Bugzilla-Product: Drivers X-Bugzilla-Component: USB X-Bugzilla-Version: 2.5 X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: stern@rowland.harvard.edu X-Bugzilla-Status: NEW X-Bugzilla-Resolution: X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: drivers_usb@kernel-bugs.kernel.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: https://bugzilla.kernel.org/ Auto-Submitted: auto-generated Precedence: bulk X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 https://bugzilla.kernel.org/show_bug.cgi?id=3D220272 --- Comment #23 from Alan Stern (stern@rowland.harvard.edu) --- Well, the new traces are a little more helpful but not much. There is essentially no difference between the initialization portions of t= he two traces. The difference shows up when you start moving the mouse. In b= oth traces the mouse sends data to the computer. In the working case, the data contains what you would expect: information about the mouse position and bu= tton presses. But in the failure case, the data contains nothing but 0's. Here's where the data starts in the working trace: ffffa25a535589c0 74469528 S Ii:1:006:1 -115:1 7 < ffffa25a535589c0 76172178 C Ii:1:006:1 0:1 7 =3D 000000ff ff0000 ffffa25a535589c0 76172197 S Ii:1:006:1 -115:1 7 < ffffa25a535589c0 76174062 C Ii:1:006:1 0:1 7 =3D 000000ff ff0000 ffffa25a535589c0 76174078 S Ii:1:006:1 -115:1 7 < ffffa25a535589c0 76176189 C Ii:1:006:1 0:1 7 =3D 000000ff ff0000 ffffa25a535589c0 76176218 S Ii:1:006:1 -115:1 7 < ffffa25a535589c0 76178108 C Ii:1:006:1 0:1 7 =3D 000000fd ff0000 ffffa25a535589c0 76178128 S Ii:1:006:1 -115:1 7 < ffffa25a535589c0 76180102 C Ii:1:006:1 0:1 7 =3D 000000fc ff0000 ffffa25a535589c0 76180126 S Ii:1:006:1 -115:1 7 < ffffa25a535589c0 76182070 C Ii:1:006:1 0:1 7 =3D 000000f9 ff0000 ffffa25a535589c0 76182086 S Ii:1:006:1 -115:1 7 < ffffa25a535589c0 76184066 C Ii:1:006:1 0:1 7 =3D 000100f7 ff0000 ffffa25a535589c0 76184081 S Ii:1:006:1 -115:1 7 < ffffa25a535589c0 76186083 C Ii:1:006:1 0:1 7 =3D 000200f5 ff0000 You can see the changing values in the two right-hand columns. Here's the corresponding portion from the failure trace: ffffa25a53558780 40179815 C Ii:1:004:1 0:1 7 =3D 00000000 000000 ffffa25a53558780 40179828 S Ii:1:004:1 -115:1 7 < ffffa25a53558780 40181774 C Ii:1:004:1 0:1 7 =3D 00000000 000000 ffffa25a53558780 40181787 S Ii:1:004:1 -115:1 7 < ffffa25a53558780 40183769 C Ii:1:004:1 0:1 7 =3D 00000000 000000 ffffa25a53558780 40183782 S Ii:1:004:1 -115:1 7 < ffffa25a53558780 40185773 C Ii:1:004:1 0:1 7 =3D 00000000 000000 ffffa25a53558780 40185783 S Ii:1:004:1 -115:1 7 < ffffa25a53558780 40187792 C Ii:1:004:1 0:1 7 =3D 00000000 000000 ffffa25a53558780 40187799 S Ii:1:004:1 -115:1 7 < ffffa25a53558780 40189792 C Ii:1:004:1 0:1 7 =3D 00000000 000000 ffffa25a53558780 40189798 S Ii:1:004:1 -115:1 7 < ffffa25a53558780 40191705 C Ii:1:004:1 0:1 7 =3D 00000000 000000 ffffa25a53558780 40191716 S Ii:1:004:1 -115:1 7 < ffffa25a53558780 40192702 C Ii:1:004:1 0:1 7 =3D 00000000 000000 ffffa25a53558780 40192705 S Ii:1:004:1 -115:1 7 < ffffa25a53558780 40193717 C Ii:1:004:1 0:1 7 =3D 00000000 000000 There's nothing to indicate why the mouse is misbehaving in this way. Mayb= e it just needs to be initialized twice before it will work right. Whatever the reason is, it certainly looks like the fault is in the mouse, not in the computer's software. Have you tried using the mouse on a different computer or under a different operating system? Also, can you try getting a trace equivalent to the failure one here, but w= ith the standard memset implementation rather than your improved one? --=20 You may reply to this email to add a comment. You are receiving this mail because: You are watching the assignee of the bug.=