From patchwork Tue Aug 30 03:12:01 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Jarkko Sakkinen X-Patchwork-Id: 12958649 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9739EECAAD2 for ; Tue, 30 Aug 2022 03:12:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229616AbiH3DMY (ORCPT ); Mon, 29 Aug 2022 23:12:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43342 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229577AbiH3DMX (ORCPT ); Mon, 29 Aug 2022 23:12:23 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 914C27F0AA; Mon, 29 Aug 2022 20:12:21 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 2CBAE6149C; Tue, 30 Aug 2022 03:12:21 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3779BC433D7; Tue, 30 Aug 2022 03:12:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1661829140; bh=x0YlO3a82EbZFbjYl7BY0zJYn245uoKtubGXUDLaGC0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ukDRAzHO07g70fKxt1F72gzET13k3CKdi6TGw67XNy2I2jKQ0dX2UUJMZ7S0mlp1o d3xKlLMdStI83ySBwfacRjQafl2rHkPIHgmkAMmG5gyTJbziyIi00Y245TkrLyO4Er O7eW/133ppQIGwlMgaCVq4+DZiFgz+MdnhQikDJ73tZeoj7Z7QK9niPPtEDawZq2YX YSlwT/9/v3klOIycd6lmT/zRij+zoL+fhzuXFBr+jerNJcXdtx3Kot7g9Coab2VQqi O6O7GrlhjbB/3sugT1V0mOVNi0f6Bba4DY7wjXZoZHXOnfRH+hgJN2/vVQPQBnrQWr p5Nu2K73oIU9A== From: Jarkko Sakkinen To: linux-sgx@vger.kernel.org Cc: Haitao Huang , Vijay Dhanraj , Reinette Chatre , Dave Hansen , Jarkko Sakkinen , Paul Menzel , Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org (maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)), "H. Peter Anvin" , linux-kernel@vger.kernel.org (open list:X86 ARCHITECTURE (32-BIT AND 64-BIT)) Subject: [PATCH 1/6] x86/sgx: Do not consider unsanitized pages an error Date: Tue, 30 Aug 2022 06:12:01 +0300 Message-Id: <20220830031206.13449-2-jarkko@kernel.org> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20220830031206.13449-1-jarkko@kernel.org> References: <20220830031206.13449-1-jarkko@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-sgx@vger.kernel.org In sgx_init(), if misc_register() for the provision device fails, and neither sgx_drv_init() nor sgx_vepc_init() succeeds, then ksgxd will be prematurely stopped. This triggers WARN_ON() because sgx_dirty_page_list ends up being non-empty, and dumps the call stack: [ 0.000000] Linux version 6.0.0-rc2 (root@4beb429beb4a) (gcc (Debian 11.3.0-3) 11.3.0, GNU ld (GNU Binutils for Debian) 2.38) #382 SMP PREEMPT_DYNAMIC Fri Aug 26 12:52:15 UTC 2022 [ 0.000000] Command line: BOOT_IMAGE=/vmlinuz-6.0.0-rc2 root=UUID=56f398e0-1e25-4fda-aa9f-611dece4b333 ro quiet module_blacklist=psmouse initcall_debug log_buf_len=4M cryptomgr.notests […] [ 0.268089] calling sgx_init+0x0/0x409 @ 1 [ 0.268103] sgx: EPC section 0x40200000-0x45f7ffff [ 0.268591] ------------[ cut here ]------------ [ 0.268592] WARNING: CPU: 6 PID: 83 at arch/x86/kernel/cpu/sgx/main.c:401 ksgxd+0x1b7/0x1d0 [ 0.268598] Modules linked in: [ 0.268600] CPU: 6 PID: 83 Comm: ksgxd Not tainted 6.0.0-rc2 #382 [ 0.268603] Hardware name: Dell Inc. XPS 13 9370/0RMYH9, BIOS 1.21.0 07/06/2022 [ 0.268604] RIP: 0010:ksgxd+0x1b7/0x1d0 [ 0.268607] Code: ff e9 f2 fe ff ff 48 89 df e8 75 07 0e 00 84 c0 0f 84 c3 fe ff ff 31 ff e8 e6 07 0e 00 84 c0 0f 85 94 fe ff ff e9 af fe ff ff <0f> 0b e9 7f fe ff ff e8 dd 9c 95 00 66 66 2e 0f 1f 84 00 00 00 00 [ 0.268608] RSP: 0000:ffffb6c7404f3ed8 EFLAGS: 00010287 [ 0.268610] RAX: ffffb6c740431a10 RBX: ffff8dcd8117b400 RCX: 0000000000000000 [ 0.268612] RDX: 0000000080000000 RSI: ffffb6c7404319d0 RDI: 00000000ffffffff [ 0.268613] RBP: ffff8dcd820a4d80 R08: ffff8dcd820a4180 R09: ffff8dcd820a4180 [ 0.268614] R10: 0000000000000000 R11: 0000000000000006 R12: ffffb6c74006bce0 [ 0.268615] R13: ffff8dcd80e63880 R14: ffffffffa8a60f10 R15: 0000000000000000 [ 0.268616] FS: 0000000000000000(0000) GS:ffff8dcf25580000(0000) knlGS:0000000000000000 [ 0.268617] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 0.268619] CR2: 0000000000000000 CR3: 0000000213410001 CR4: 00000000003706e0 [ 0.268620] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 0.268621] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 0.268622] Call Trace: [ 0.268624] [ 0.268627] ? _raw_spin_lock_irqsave+0x24/0x60 [ 0.268632] ? _raw_spin_unlock_irqrestore+0x23/0x40 [ 0.268634] ? __kthread_parkme+0x36/0x90 [ 0.268637] kthread+0xe5/0x110 [ 0.268639] ? kthread_complete_and_exit+0x20/0x20 [ 0.268642] ret_from_fork+0x1f/0x30 [ 0.268647] [ 0.268648] ---[ end trace 0000000000000000 ]--- [ 0.268694] initcall sgx_init+0x0/0x409 returned -19 after 603 usecs Ultimately this can crash the kernel, if the following is set: /proc/sys/kernel/panic_on_warn Print a simple warning instead, and improve the output by printing the number of unsanitized pages, in order to provide debug informnation for future needs. Link: https://lore.kernel.org/linux-sgx/20220825051827.246698-1-jarkko@kernel.org/T/#u Reported-by: Paul Menzel Tested-by: Paul Menzel Fixes: 51ab30eb2ad4 ("x86/sgx: Replace section->init_laundry_list with sgx_dirty_page_list") Signed-off-by: Jarkko Sakkinen --- Cc: Haitao Huang Cc: Dave Hansen Cc: Reinette Chatre v5: - Add the klog dump and sysctl option to the commit message. v4: - Explain expectations for dirty_page_list in the function header, instead of an inline comment. - Improve commit message to explain the conditions better. - Return the number of pages left dirty to ksgxd() and print warning after the 2nd call, if there are any. v3: - Remove WARN_ON(). - Tuned comments and the commit message a bit. v2: - Replaced WARN_ON() with optional pr_info() inside __sgx_sanitize_pages(). - Rewrote the commit message. - Added the fixes tag. --- arch/x86/kernel/cpu/sgx/main.c | 19 +++++++++++++------ 1 file changed, 13 insertions(+), 6 deletions(-) diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c index 515e2a5f25bb..903100fcfce3 100644 --- a/arch/x86/kernel/cpu/sgx/main.c +++ b/arch/x86/kernel/cpu/sgx/main.c @@ -49,17 +49,20 @@ static LIST_HEAD(sgx_dirty_page_list); * Reset post-kexec EPC pages to the uninitialized state. The pages are removed * from the input list, and made available for the page allocator. SECS pages * prepending their children in the input list are left intact. + * + * Contents of the @dirty_page_list must be thread-local, i.e. + * not shared by multiple threads. */ -static void __sgx_sanitize_pages(struct list_head *dirty_page_list) +static int __sgx_sanitize_pages(struct list_head *dirty_page_list) { struct sgx_epc_page *page; + int left_dirty = 0; LIST_HEAD(dirty); int ret; - /* dirty_page_list is thread-local, no need for a lock: */ while (!list_empty(dirty_page_list)) { if (kthread_should_stop()) - return; + break; page = list_first_entry(dirty_page_list, struct sgx_epc_page, list); @@ -92,12 +95,14 @@ static void __sgx_sanitize_pages(struct list_head *dirty_page_list) } else { /* The page is not yet clean - move to the dirty list. */ list_move_tail(&page->list, &dirty); + left_dirty++; } cond_resched(); } list_splice(&dirty, dirty_page_list); + return left_dirty; } static bool sgx_reclaimer_age(struct sgx_epc_page *epc_page) @@ -388,6 +393,8 @@ void sgx_reclaim_direct(void) static int ksgxd(void *p) { + int left_dirty; + set_freezable(); /* @@ -395,10 +402,10 @@ static int ksgxd(void *p) * required for SECS pages, whose child pages blocked EREMOVE. */ __sgx_sanitize_pages(&sgx_dirty_page_list); - __sgx_sanitize_pages(&sgx_dirty_page_list); - /* sanity check: */ - WARN_ON(!list_empty(&sgx_dirty_page_list)); + left_dirty = __sgx_sanitize_pages(&sgx_dirty_page_list); + if (left_dirty) + pr_warn("%d unsanitized pages\n", left_dirty); while (!kthread_should_stop()) { if (try_to_freeze())