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 59A392E82A for ; Fri, 24 Nov 2023 15:27:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="B+EQQB6x" Received: by smtp.kernel.org (Postfix) with ESMTPS id C291AC433CB for ; Fri, 24 Nov 2023 15:27:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1700839634; bh=T925OAW1mAC5k6Acpoghglvma5Yx2ywJVe3f3wXgzEk=; h=From:To:Subject:Date:In-Reply-To:References:From; b=B+EQQB6xz/W2zQn9cv0pMyOc7+XMAKCxWzyK3oqwPOUPSom6bJXwGT9ctikJFJXX/ nsO3Q4E9naWisKf1M9pe1DLafZpPdXX3/hwMyQg9EuftCP1fCOoJKdGhd885eAicP1 Zw/Rhl+xhraRTo9NTVkbUiSwali2dbdDa+IaQV9Kv2cdPgGRia0dgEGih7czJT0hDK ofYszJW7ZFXwJTy9m7Q2XEK9/KJzWZ8xuIEd0eobny+jgdiiyQ2igCDhvlod6pvGOc 6grzZAFmtkiutsty0zMCelSVh6+ZQPXTRn675Rrmm7VKlcWtb7+8yvKirIjR0QkNVB U2FzSolthUevA== Received: by aws-us-west-2-korg-bugzilla-1.web.codeaurora.org (Postfix, from userid 48) id AC4FCC53BC6; Fri, 24 Nov 2023 15:27:14 +0000 (UTC) From: bugzilla-daemon@kernel.org To: linux-usb@vger.kernel.org Subject: [Bug 215740] kernel warning: DMA-API: xhci_hcd: cacheline tracking EEXIST, overlapping mappings aren't supported Date: Fri, 24 Nov 2023 15:27:14 +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: P1 X-Bugzilla-Assigned-To: drivers_usb@kernel-bugs.kernel.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: cc 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=3D215740 Alan Stern (stern@rowland.harvard.edu) changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |dan.j.williams@intel.com, | |hch@lst.de --- Comment #23 from Alan Stern (stern@rowland.harvard.edu) --- +Christoph Hellwig (because I am not an expert on kmalloc and cache line alignment) Ferry: Sorry about the malformed patches. The bad line was added automatic= ally by Quilt (I don't know why). If I add any more patches, I'll try to rememb= er to remove that bogus line first. Andy: There are two mappings in question here, both of them are reads, neit= her is larger than 8 bytes, and neither has a cache line alignment requirement (other than the general restriction that on architectures with non-cache-coherent DMA -- i.e., not x86 -- different allocations should bel= ong to different cache lines). The first mapping is 1 byte long (at the start of the 8-byte-long hub->buff= er allocated near the beginning of hub_configure() in drivers/usb/core/hub.c) = and the second is 4 bytes long (for hub->status, allocated just afterward). The physical addresses and sizes of the mappings, as shown in the log, are: hub->buffer: 108342600 size 1 hub->status: 108342608 size 4 Obviously they lie in the same cache line, which is what triggers the DMA debugging error. But equally obviously, on x86 or other architectures with cache-coherent DMA, there is nothing wrong with them. Incidentally, --=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.=