From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 B90CF256C84; Tue, 21 Jul 2026 15:56:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784649414; cv=none; b=JTnfG1ZufJxceciToEIocgWYXJoNcJOA1/CUcUHnW2utfLRCUNQRlQGYZwiY0oyzCkGuXTJ8icBvJwhIYGkZiiPd1/ocRIdShITfbAW9X0qmSYv+GAY0eNlrYw/HJU3p0/d2GUNasqVyTuLecmCFWtSkBe/LItgEfLQS9JAQ/xY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784649414; c=relaxed/simple; bh=eIVg3mheZg8mW+U7xvsxbovmogUHUv7Rkf/mDmzaZHg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=r3/mHMEN4X0bcIgVoq/hDiA40MuYmZ4H0/dWqQMOZAUYRRG/7TpC8FdImkWz9WCCYrbYVsHDhS12SIMvw+9sDV8XZds3nmg9f6Q5InLKL1ZRGCkW9np46PMAm9FtqfMjqQc49hqGE7sVEwwV1VKtBHH77eU85wJRa2Y3w1k5XMo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=xPSx1VCf; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="xPSx1VCf" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1F85B1F00A3D; Tue, 21 Jul 2026 15:56:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784649413; bh=HJay47GhelGTuN8mIo0cZQXybVQMYKNy0O7av5q/UrQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=xPSx1VCfu9k0t2sPey73iGCXuq4Ce77x7IhTCenqqWM7g1w3BPlhkmwoaBS3I1SPW FCSPaY1AUcryw3W0p06yZ6PqLCzHuGCGafLPq7fbdfOdnJQ/qx2O0z0jQuuU0MGUSk opQi2OatH2FYLqGtoOpfgWObXlTR0r22/KF4uYAk= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Ankit Soni , Jason Gunthorpe , Sasha Levin Subject: [PATCH 7.1 0569/2077] iommufd: Take dma_resv lock before dma_buf_unpin() in release path Date: Tue, 21 Jul 2026 17:04:02 +0200 Message-ID: <20260721152606.230162824@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260721152552.646164743@linuxfoundation.org> References: <20260721152552.646164743@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 7.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ankit Soni [ Upstream commit e745cd2c749e557c14a15ac931761c3f58c24489 ] 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: WARNING: drivers/dma-buf/dma-buf.c:1137 at dma_buf_unpin+0x62/0x70 RIP: 0010:dma_buf_unpin+0x62/0x70 Call Trace: dma_buf_unpin+0x62/0x70 iopt_release_pages+0xe4/0x190 iopt_unmap_iova_range+0x1c7/0x290 iopt_unmap_all+0x1a/0x30 iommufd_ioas_destroy+0x1d/0x50 iommufd_fops_release+0x93/0x150 __fput+0xfc/0x2c0 __x64_sys_close+0x3d/0x80 do_syscall_64+0x65/0x180 Take the dma_resv lock around dma_buf_unpin() in iopt_release_pages(), matching the iopt_map_dmabuf() convention. dma_buf_detach() acquires the reservation lock internally, so it must remain outside the locked region. Fixes: 8c5f9645c389 ("iommufd: Add dma_buf_pin()") Link: https://patch.msgid.link/r/20260526111034.4079-1-Ankit.Soni@amd.com Reported-by: Ankit Soni Signed-off-by: Ankit Soni Signed-off-by: Jason Gunthorpe Signed-off-by: Sasha Levin --- drivers/iommu/iommufd/pages.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/iommu/iommufd/pages.c b/drivers/iommu/iommufd/pages.c index 9bdb2945afe1eb..7b64002e54b9a2 100644 --- a/drivers/iommu/iommufd/pages.c +++ b/drivers/iommu/iommufd/pages.c @@ -1663,7 +1663,9 @@ void iopt_release_pages(struct kref *kref) if (iopt_is_dmabuf(pages) && pages->dmabuf.attach) { struct dma_buf *dmabuf = pages->dmabuf.attach->dmabuf; + dma_resv_lock(dmabuf->resv, NULL); dma_buf_unpin(pages->dmabuf.attach); + dma_resv_unlock(dmabuf->resv); dma_buf_detach(dmabuf, pages->dmabuf.attach); dma_buf_put(dmabuf); WARN_ON(!list_empty(&pages->dmabuf.tracker)); -- 2.53.0