From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-qk1-f175.google.com (mail-qk1-f175.google.com [209.85.222.175]) (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 23EC03F871B for ; Tue, 26 May 2026 12:26:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.222.175 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779798420; cv=none; b=uEOPQKSHxgnCUxrotupKSJ4JceRuWKz254ipPKFeMDEveGfyQGNJwlFKa4NsrRqQ5TQj36WR2klZnaFbiB6nv4VZYfAMeAleK1l6y0iVMbKh7Y2o/ox0zBu/fzF26+8s1ltMWTWbb5ryBEqQfA4lOK5YDdHvKurfJofAIE8qzng= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779798420; c=relaxed/simple; bh=ehL5g3u352wzk/u26D6x4hHM2Xz657v/SQyqW4yRuEo=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=ZVXKMSN/d8Hh72bkzKqDv6Buh3LwCT2jToMacwtGfAOLNUfqkFKw56k1OMzRChofnVfZLX7Nep81aa93uUbMHEmIr9+FG3w4qzxIOYnvurPbrHl1jciGLlXjSdq2nha1WoKBKOhlzYEHEIUjt4+6BE9V1tw1303nTLJPp74bznc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=ziepe.ca; spf=pass smtp.mailfrom=ziepe.ca; dkim=pass (2048-bit key) header.d=ziepe.ca header.i=@ziepe.ca header.b=CegQkZ1g; arc=none smtp.client-ip=209.85.222.175 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=ziepe.ca Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ziepe.ca Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=ziepe.ca header.i=@ziepe.ca header.b="CegQkZ1g" Received: by mail-qk1-f175.google.com with SMTP id af79cd13be357-911dfc86903so1223810185a.3 for ; Tue, 26 May 2026 05:26:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ziepe.ca; s=google; t=1779798418; x=1780403218; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=QQVPF5z8tEWy9hSyAGSwHCVBtb21IOuG2HFA7xrSBPI=; b=CegQkZ1g89NARdLWkEKXkP9zFEb3QDJ8ANioo+++6RPpDeEykh6l05ZnB6261wXW8/ dC43CBwHGlBTcodBENPgjP3rXZNq9Hqz10GiCAnBNiCO6SL9ixaMwk1Gn+fyVS4Chl+D NRTxDZ61ofcfCg+eBZkYcwyZn3B5CId/ec91hL5cdaT+/3J7VDvrGVu7MF6Hl9rMxCUC TsLDQGoAk6JgWvPFyKGUxlTWv6X4SDwPU5a41DmhLCtaA/0/jCAWkNwas4zWd6IjfCFF ZsydgD1CkiSD69BgMToGz6uyGsZ9I5ZP5toy6xJkNDtG7zkZFRFcN+7jiFtUkPXj8g/3 52Cg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1779798418; x=1780403218; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-gg:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=QQVPF5z8tEWy9hSyAGSwHCVBtb21IOuG2HFA7xrSBPI=; b=KXod403LlcsLEdD9Hjr2xR8AOZqkvzPXjgd4V9rJEcRc8YXJobbWMnPu2xsey3BUJ+ WZmIIs7Y82JuxWX/6xie2mSCW1p8FN+rUaExWNivrwf99YmChpt0NFkOjgDmj13l0kMb 3M4ONzGwfWvGgoXYC2zKGbkL5Lt7OvE6JjEMYLVBu7xXX14vO3A3D8VzKVwe+iM+26fA 1zrS2wDL1AgvzjdMvtPsflbwZ2EoIR93TvIcP715qVmtlXuanL/OccuGrZPRkIv0qlRL Awnh3rUS9m3Ummr3iv+nQ30Rp2rFT2nXKkxmz5ODaMZWOLLgoKX65WXB9jTzdxyrkEaE NCzg== X-Forwarded-Encrypted: i=1; AFNElJ8N/68Z0DoSUlNPHOUwnndwfTH0ot3LJQPmFFxVJUc/eMYx0eIT/Ug57Nfa094ZD977gTrbOFW73+1Bz3I=@vger.kernel.org X-Gm-Message-State: AOJu0Yw8yXOb1uW9Z3vaO/Jes6f+jW9FO9rqlPFOyuvR4/LIsF/ohhrr q4g6WWzczFrEiMcvgHVS/+qs4NdHi2r7GSpTofyVWiqhtki66XtSEy0DsoDqrngKWEdkyi9lSgE mCiDu X-Gm-Gg: Acq92OEOUsolY16vl+XWyoHewTfGx9CnBc00x0ozGM4VKY+32Q3/+FCVrwxevSzUl+6 ++el0+hGpzUYAgtpQtAv4Ierpa7c5q2f1kFdXpLNnSjEEA4Qx1t2cIUYPVYJqnly0j0wHxBhjcA KwhIQNLMvzYeC0K1O3nZ7NvFSmvfl45eqiu07OCLtnYYH0goPGKh3ecSLdT0nLADih2QYZ25d1+ zdonF5IAYTxtXY4Uo2bIncxOnvvRw9S7+84gnlSr9Ax0bRE5frc287vjp6mj9LPejmULWDBXRuu ApKu1s/dxfR5CHFU8gMGGURlZe3rJn7n6+XExW12CD+/pyZyW9xSijRpQI2nfP2TVakxDDFKLrW PWcRaJ6iJ1CojbHwCQRvD+ppl6UYj75Onca8v01gRLKECMEzrrGU061HBKQbFI0OcWHoG899+/Y w+Lrk06lTJ8j6VkUG8i9yYHet37P4FfvkvQMGKt5I9a8geqUz95BvaJIpb/iv2zYq/iniYyFhuQ OJIjV6KbUYdfFwi X-Received: by 2002:a05:620a:29d5:b0:914:c7b6:e29c with SMTP id af79cd13be357-914c7b6e6a4mr1836526485a.56.1779798418003; Tue, 26 May 2026 05:26:58 -0700 (PDT) Received: from ziepe.ca (crbknf0213w-47-54-130-67.pppoe-dynamic.high-speed.nl.bellaliant.net. [47.54.130.67]) by smtp.gmail.com with ESMTPSA id af79cd13be357-914f8801390sm215458285a.36.2026.05.26.05.26.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 26 May 2026 05:26:57 -0700 (PDT) Received: from jgg by wakko with local (Exim 4.97) (envelope-from ) id 1wRqs4-0000000DONN-3pnp; Tue, 26 May 2026 09:26:56 -0300 Date: Tue, 26 May 2026 09:26:56 -0300 From: Jason Gunthorpe To: Ankit Soni Cc: Kevin Tian , Joerg Roedel , Will Deacon , Robin Murphy , Sumit Semwal , Christian =?utf-8?B?S8O2bmln?= , Leon Romanovsky , Vasant Hegde , iommu@lists.linux.dev, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, linux-media@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] iommufd: take dma_resv lock before dma_buf_unpin() in release path Message-ID: <20260526122656.GE2487554@ziepe.ca> References: <20260526111034.4079-1-Ankit.Soni@amd.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260526111034.4079-1-Ankit.Soni@amd.com> On Tue, May 26, 2026 at 11:10:34AM +0000, Ankit Soni wrote: > dma_buf_unpin() requires the caller to hold the exporter's dma_resv > lock: > > void dma_buf_unpin(struct dma_buf_attachment *attach) > { > ... > dma_resv_assert_held(dmabuf->resv); > ... > } > > iopt_release_pages() calls dma_buf_unpin() without taking that lock, > so every iommufd_ioas_destroy()/iommufd_ioas_unmap() that releases > the last reference on a DMABUF-backed iopt_pages triggers a WARN. > This was hit while running tools/testing/selftests/iommu/iommufd: Any idea why this is comming up now? Did I run the tests without some kind of debug option to turn on that assertion maybe? Jason