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 2FF2B34FF45 for ; Thu, 26 Mar 2026 19:46:33 +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=1774554393; cv=none; b=hTH0SUuYG3fPghvjLPqKtssgP+aMrZzzOk22ote4f3Pz9uipA9jfSEOGTryzAG7OH0fAEpR37zg6HSEOC9slGWwbuRJyWnD1d4YMnvnzbzdr2+z+w8lYXYrLpAQFfw/hmALq2Dyl+rBhfn5XDu0k4KdtIerXjRkExvKnPAlrYQM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774554393; c=relaxed/simple; bh=c2IVIePw9exRcgvboOiFZIPfTHGl2gVwM6kP2dgzG7E=; h=From:To:Subject:Date:Message-ID:In-Reply-To:References: Content-Type:MIME-Version; b=C8rFwMVXsC0dzIO3id4K4muDphfMjMSnhkLVO1+uDnManlBwC7HRPqW1tDZ1NURCJ/zstwRDH6Mtm04KiputrCAiTRYN+8rM3LUlTMqJ03h3tiI07kaF4pdlc/jGuaoU27BfhpEOR1xe4OVGTRHPBnlQlKKzuURB0DVwh7XkVA8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=jg72Ar9I; 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="jg72Ar9I" Received: by smtp.kernel.org (Postfix) with ESMTPS id D5BE6C19423 for ; Thu, 26 Mar 2026 19:46:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1774554392; bh=c2IVIePw9exRcgvboOiFZIPfTHGl2gVwM6kP2dgzG7E=; h=From:To:Subject:Date:In-Reply-To:References:From; b=jg72Ar9IzpSh1A0/dalEcGqAhSJN1WFcN3vbxKLmyNts/dhMTIs7+QULuR/D2GVSO t62Sb5nAe0xOZHKzNzyIDJx5a1jzeupO+SuPbDF7vjWcmlbePd67DR3CZQEgHC3F/i X0AMDKi6SbVFizPKZuKVgtO+BHsCm+5dX3crcWWaHpTvn9bL+CNYt5k6nyXCyWoIG0 DfHAQXayMKIFWYWCHrmx9SFtTVoFcT8Ma5K06FdfofmkUiQ8Dgg1O2kMUBdR3ijDnu ICTLL/35eISyrmI5sy3ck/eg6+/SmvvGrvWKwH7o61DR9O54DVXJkrqdaKjDnkrRgB g1fyFwQ1CIajw== Received: by aws-us-west-2-korg-bugzilla-1.web.codeaurora.org (Postfix, from userid 48) id CF771C4160E; Thu, 26 Mar 2026 19:46:32 +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: Thu, 26 Mar 2026 19:46:32 +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: mikhail.v.gavrilov@gmail.com 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 attachments.created 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 Mikhail (mikhail.v.gavrilov@gmail.com) changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |mikhail.v.gavrilov@gmail.co | |m --- Comment #51 from Mikhail (mikhail.v.gavrilov@gmail.com) --- Created attachment 309769 --> https://bugzilla.kernel.org/attachment.cgi?id=3D309769&action=3Dedit dma_cacheline_eexist_repro.mod.c I hit this exact warning on 7.0-rc5 with an ASUS USB Audio device (0b05:1a5c) on AMD B650E (ROG STRIX B650E-I) + xhci_hcd 0000:0c:00.0. Same stack trace through snd_usb_ctl_msg -> usb_control_msg -> usb_hcd_map_urb_for_dma -> dma_map_phys -> add_dma_entry -> EEXIST. I tested Guenter's patch from comment #43 (ARCH_KMALLOC_MINALIGN =3D L1_CACHE_BYTES when CONFIG_DMA_API_DEBUG) and can confirm it fixes the issue. I also wrote a kernel module reproducer that triggers the bug reliably on demand, without needing to wait for a specific USB device to be plugged in during boot. The module does exactly what hub_configure() does: two kmalloc(8) allocations back-to-back, then DMA-maps both. On x86_64 with ARCH_KMALLOC_MINALIGN=3D8, they land in the same 64-byte cacheline within ~50 attempts, triggering the EEXIST warning. Before fix: dma_repro: pair 53: buf_a=3Dffff8881c8f9eb80 buf_b=3Dffff8881c8f9eba0 -- SAME cacheline 119793582! DMA-API: cacheline tracking EEXIST, overlapping mappings aren't supported After fix (ARCH_KMALLOC_MINALIGN >=3D L1_CACHE_BYTES): dma_repro: no same-cacheline pair found in 64 attempts (ARCH_KMALLOC_MINALIGN may already be >=3D cache_line_size) I can submit a formal patch based on Guenter's fix if nobody objects. Reproducer module source attached. --=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.=