From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793211804; b=2o62wP/DZllxLZt4doqkOK658LgIrTHygRswbAzuStzxr6HnlvXhl/t6hvDvTWkcFW+w dv7ZRK9HkQ28iIQlvWRfq8S32VhpiWS6/J4EVmcK0BS80JlV2YasygtPn+PScUjBYl60f XMWA86Rth3yx1N6xRjBGpPfrOpP5VPJYrASCwUXW6ldu/60P69zIA1yF6yhfGzSDDqgcA DBI/Iv2goFE9guVYUy/psdp1DJt6+dZo4jC785xWabACXgXrEKQTDbuFM0fb8T+6jSC3p OrUSnKt/kaxXX1t9YXFKULlPma8kkG83NmQMAc9D+sOxInKAJwPJZif1aMIGhOguB8w== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793211804; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=2Sas+5xZIUWHZktq1fV6fZGMw5BL6irVRuehewH2eqM=; b=agu0UqYl9aTakIXUwrwZecAOxDcfevmVnOgjQT5hG+378GAlbWw/1CxJO6KlMTtX56Q1 dpCpr5sG38yTtNo3QZfsiOinWlcEP8Q6VryssALYWmhHU1Bk+e7TGE/xXjLPtrt9h0F9q VX1L39sxb0BXbaeJFdFyin+aahEgJ3KjFdSUvqKfPpm5LWoafntTZfTQUXC3lU2YZWQmH fJU82VbOEhGbndYuA/pCNf5yaaejzhn+RU0GQ1QfU6IMupevA6H3272AWvNUC5jUzWV7y yHO+cvLaGcpTWK3fsgtuPnh1rOUwjYvwj27IVepoPEzytXaejbT2NbDWkfhT4leDqeA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=JEndXbMT; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E8089606A31A; Wed, 28 Oct 2026 18:23:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=JEndXbMT Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4378A1F01825; Wed, 28 Oct 2026 18:23:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793211803; bh=2Sas+5xZIUWHZktq1fV6fZGMw5BL6irVRuehewH2eqM=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=JEndXbMT3O95/4KEhckV9W4r+mkfSYwJoajAqxdswQmYbKiUXoDyRd9QoxgmJhGkj yLodS1U25eVC/ul8ZDfos3HH9jvQyn4sf0H6hPRN6Apfx02HxPbk6zr4ZJhLaBN1h5 ZyHQxU9+kA/rTcJViblHNmo9pftipAGpNknsldHo= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Alex Deucher , Jesse Zhang Subject: [PATCH 5.15 504/571] drm/amdgpu: dont drop the runtime PM reference twice in amdgpu_gpr Date: Wed, 28 Oct 2026 18:00:51 +0100 Message-ID: <20261028170019.989426334@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261028170008.009143722@linuxfoundation.org> References: <20261028170008.009143722@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jesse Zhang commit de9f6bcdb44f0e410031002e2f103826ea6b6259 upstream. amdgpu_debugfs_gpr_read() drops its runtime PM reference right after reading the wave registers. When copying them to userspace fails, it jumps to the err label, which drops the reference a second time. A read into a bad buffer on Navi31 either steals a reference somebody else holds (power/runtime_usage goes from 1 to 0) or underflows the count: amdgpu 0000:03:00.0: Runtime PM usage count underflow! The registers are already in the kernel buffer at that point, so finish the hardware access first and copy the buffer with a single copy_to_user() instead of the put_user() loop with its own error path. Fixes: 9eee152aab56 ("drm/amdgpu/debugfs: fix ref count leak when pm_runtime_get_sync fails") Reviewed-by: Alex Deucher Signed-off-by: Jesse Zhang Signed-off-by: Alex Deucher (cherry picked from commit 31035bbd74f7c3e10c163db875b8e67f8b50ee6a) Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c | 21 +++------------------ 1 file changed, 3 insertions(+), 18 deletions(-) --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c @@ -858,7 +858,6 @@ static ssize_t amdgpu_debugfs_gpr_read(s { struct amdgpu_device *adev = f->f_inode->i_private; int r; - ssize_t result = 0; uint32_t offset, se, sh, cu, wave, simd, thread, bank, *data; if (size > 4096 || size & 3 || *pos & 3) @@ -903,25 +902,11 @@ static ssize_t amdgpu_debugfs_gpr_read(s pm_runtime_mark_last_busy(adev_to_drm(adev)->dev); pm_runtime_put_autosuspend(adev_to_drm(adev)->dev); + amdgpu_virt_disable_access_debugfs(adev); - while (size) { - uint32_t value; - - value = data[result >> 2]; - r = put_user(value, (uint32_t *)buf); - if (r) { - amdgpu_virt_disable_access_debugfs(adev); - goto err; - } - - result += 4; - buf += 4; - size -= 4; - } - + r = copy_to_user(buf, data, size) ? -EFAULT : size; kfree(data); - amdgpu_virt_disable_access_debugfs(adev); - return result; + return r; err: pm_runtime_put_autosuspend(adev_to_drm(adev)->dev);