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=1792774050; b=SZI+KlZ+SguAlQW50cqMdG1BIWloSeyWcTqJXKPXgy1fpiKMhKHfhXFs2dPUlC+wtp22 nkELZPEq4P8fvaW/he/zrFbS/LUlRWrzkG6y7gbn3511FiceuMFlCMdot7PefKEKewgSX tE4JlXSnMbzvZdZx4D4zdcqyr3fx6nZuYXR/ZAaWGWwVCzXaI457cmNPvrdn7bwBSPthp zo2RrHX4kBKo3bR14ofw1MwL6PfKfiMNCO3S3aI1pXtrRFQCIIOghu3aD2y7PVOYiRdjl AfU3d5t34SIk/VLZv7HBDsE4mrQtWs/l6lpcepyqibUoDVIbWet4ex9AtMcDCAGhoNQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792774050; 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=UBClsWiBaGLky5IanREps6N1tTYG+CyM/VGsbaR67wU=; b=uIy/tRr1YOtMEZBrlzUd3F7b11BKOAgvDIpH9kEwnBNBn65IaokbY2RvXe/lqXCL4f4I iOGZuUuTInas5CpFBb7B5fovACeNAexgfX40xciemduhEo7wuVi/3Pmf6e2IhQ6llRHa7 SqU7PNX7Lvk09l6tTpU4xJXed4RBQOvbcXgclqFBxzN3rdhnfwY5OB2P4vEPkXG7G88Y5 mRV3AsM61XuOL0M9pNKJdqhFtB2nSn7runT9p+9Oa4Dpy7z/Qfie58yaxdaMGbga2wXjM V5vJrgfpbrJJJO42dg+M5jF95ITFRrYwVavH7JPlpLOG+OEV++4jcyXt+6djFNbThCA== 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=c0ayC6jo; 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 07040606A31B; Fri, 23 Oct 2026 16:47:30 +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=c0ayC6jo Received: by smtp.kernel.org (Postfix) with ESMTPSA id 540BF1F01825; Fri, 23 Oct 2026 16:47:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1792774049; bh=UBClsWiBaGLky5IanREps6N1tTYG+CyM/VGsbaR67wU=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=c0ayC6jodAs/A4POCXZkwBHJrN5/pvVE45W1Zkl7NSgs/b1N4Y88odhFUOnme1YzW qR4frF6pm8N2dJRi0CkyP9Rx6JrgWVQqQ6ap55YKKf94tyyuxeZF7TjPQP8HUzclqU LPYekkWTEsXjkdWByJ8GxObKo41ywSGtBWFM5SR0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Alex Deucher , Jesse Zhang Subject: [PATCH 6.18 105/193] drm/amdgpu: dont drop the runtime PM reference twice in amdgpu_gpr Date: Fri, 23 Oct 2026 18:36:22 +0200 Message-ID: <20261023163716.691594655@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261023163714.201276352@linuxfoundation.org> References: <20261023163714.201276352@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 6.18-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 @@ -1164,7 +1164,6 @@ 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) @@ -1209,25 +1208,11 @@ 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);