From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-14.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A8E57C433E1 for ; Thu, 27 Aug 2020 14:51:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7389E2054F for ; Thu, 27 Aug 2020 14:51:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598539867; bh=fa2DrFabyT+DIgMoyFlHqZqjS5ow1whM7k7eYT1K05s=; h=From:To:Cc:Subject:Date:List-ID:From; b=XEpe7MBu5GP3Fdhv2y2KYrMPYSMDnMSwCeMubmSvjjqv2vnWThRrCpt/sJ9jYStV9 z53HBiiEemA503G8+EbrJuzffQ7kM+XauWTAVWkFxCVIsrL9oopKqFZ7svD1gAVPCq Hz0DquoUMgYunrJBBlqQo43BdUm7XqVvUOh6+uUI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728268AbgH0OvG (ORCPT ); Thu, 27 Aug 2020 10:51:06 -0400 Received: from mail.kernel.org ([198.145.29.99]:34300 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727888AbgH0Njk (ORCPT ); Thu, 27 Aug 2020 09:39:40 -0400 Received: from localhost (unknown [213.57.247.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 6DF87207CD; Thu, 27 Aug 2020 13:39:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598535579; bh=fa2DrFabyT+DIgMoyFlHqZqjS5ow1whM7k7eYT1K05s=; h=From:To:Cc:Subject:Date:From; b=VcaXRBZrFysXMNq+OW5DxhzIcbVXgzkyKUjruY7k0/vx4kmNTgH4WL+CyoE9tKMj2 dth5Ok8lYG3OSDqO24LMuammHM+h6KXD7Wpe9aH0uKbYdU88rSMhffXkpomz5MTu7b GOejBpNGPLqso9z7aMdYlJ00BZevjwswmtFxwnXk= From: Leon Romanovsky To: Peter Oberparleiter , Andrew Morton Cc: Leon Romanovsky , Colin Ian King , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [RFC PATCH -rc] gcov: Protect from uninitialized number of functions provided by GCC Date: Thu, 27 Aug 2020 16:39:32 +0300 Message-Id: <20200827133932.3338519-1-leon@kernel.org> X-Mailer: git-send-email 2.26.2 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Leon Romanovsky The kernel compiled with GCC 10.2.1 and KASAN together with GCOV enabled produces the following splats while reloading modules. First splat [1] is generated due to the situation that gcov_info can be both user and kernel pointer, the memcpy() during kmemdup() causes to this. As a possible solution copy fields manually. Second splat [2] is seen because n_function provided by GCC through __gcov_init() is ridiculously high, in my case it was 2698213824. IMHO it means that this field is not initialized, but I'm not sure. [1] ================================================================== BUG: KASAN: global-out-of-bounds in kmemdup+0x43/0x70 Read of size 120 at addr ffffffffa0d2c780 by task modprobe/296 CPU: 0 PID: 296 Comm: modprobe Not tainted 5.9.0-rc1+ #1860 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04 /01/2014 Call Trace: ? dump_stack+0x128/0x1af ? print_address_description.constprop.0+0x2c/0x3f0 ? _raw_spin_lock_irqsave+0x34/0xa0 ? __kasan_check_read+0x1d/0x30 ? kmemdup+0x43/0x70 ? kmemdup+0x43/0x70 ? gcov_info_dup+0x2d/0x730 ? __kasan_check_write+0x20/0x30 ? __mutex_unlock_slowpath+0x10d/0x740 ? gcov_event+0x88d/0xd30 ? gcov_module_notifier+0xe9/0x100 ? notifier_call_chain+0xeb/0x170 ? blocking_notifier_call_chain+0x75/0xc0 ? __x64_sys_delete_module+0x326/0x5a0 ? do_init_module+0x810/0x810 ? syscall_enter_from_user_mode+0x40/0x420 ? trace_hardirqs_on+0x45/0xb0 ? syscall_enter_from_user_mode+0x40/0x420 ? do_syscall_64+0x45/0x70 ? entry_SYSCALL_64_after_hwframe+0x44/0xa9 The buggy address belongs to the variable: __gcov_.uverbs_attr_get_obj+0x60/0xfffffffffff778e0 [mlx5_ib] Memory state around the buggy address: ffffffffa0d2c680: 00 f9 f9 f9 f9 f9 f9 f9 00 00 00 00 00 f9 f9 f9 ffffffffa0d2c700: f9 f9 f9 f9 00 00 00 00 00 f9 f9 f9 f9 f9 f9 f9 >ffffffffa0d2c780: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 f9 f9 ^ ffffffffa0d2c800: f9 f9 f9 f9 00 00 00 00 00 f9 f9 f9 f9 f9 f9 f9 ffffffffa0d2c880: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ================================================================== Disabling lock debugging due to kernel taint gcov: could not save data for '/home/leonro/src/kernel/drivers/infiniband/hw/mlx5/std_types.gcda' (out o f memory) [2] Colin has similar error [3]. ------------[ cut here ]------------ WARNING: CPU: 0 PID: 296 at mm/page_alloc.c:4859 __alloc_pages_nodemask+0x670/0x3190 Modules linked in: mlx5_ib(-) mlx5_core mlxfw ptp ib_ipoib pps_core rdma_ucm rdma_cm iw_cm ib_cm ib_umad ib_uverbs ib_core CPU: 0 PID: 296 Comm: modprobe Tainted: G B 5.9.0-rc1+ #1860 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04 /01/2014 RIP: 0010:__alloc_pages_nodemask+0x670/0x3190 Code: e9 af fc ff ff 48 83 05 fd 28 90 05 01 81 e7 00 20 00 00 48 c7 44 24 28 00 00 00 00 0f 85 fb fd ff ff 48 83 05 f0 28 90 05 01 <0f> 0b 48 83 05 ee 28 90 05 01 48 83 05 ee 28 90 05 01 e9 dc fd ff RSP: 0018:ffff88805f7ffa28 EFLAGS: 00010202 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 1ffff1100befff5e RDX: 0000000000000000 RSI: 0000000000000017 RDI: 0000000000000000 RBP: 000000050695a900 R08: ffff888060fc7900 R09: ffff888060fc793b R10: ffffed100c1f8f27 R11: ffffed100c1f8f28 R12: 0000000000040dc0 R13: 000000050695a900 R14: 0000000000000017 R15: 0000000000000001 FS: 00007f521f695740(0000) GS:ffff88806ce00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f31b013f000 CR3: 000000006637e001 CR4: 0000000000370eb0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: ? __kmalloc_track_caller+0x17a/0x570 ? gcov_info_dup+0xfe/0x730 ? gcov_event+0x88d/0xd30 ? gcov_module_notifier+0xe9/0x100 ? blocking_notifier_call_chain+0x75/0xc0 ? __x64_sys_delete_module+0x326/0x5a0 ? entry_SYSCALL_64_after_hwframe+0x44/0xa9 ? mark_lock+0xba0/0xba0 ? mark_lock+0xba0/0xba0 ? notifier_call_chain+0xeb/0x170 ? blocking_notifier_call_chain+0x75/0xc0 ? __x64_sys_delete_module+0x326/0x5a0 ? do_syscall_64+0x45/0x70 ? entry_SYSCALL_64_after_hwframe+0x44/0xa9 ? warn_alloc+0x130/0x130 ? lock_acquire+0x1f2/0xa30 ? fs_reclaim_acquire+0x1f/0x70 ? fs_reclaim_release+0x1f/0x50 ? __kasan_check_read+0x1d/0x30 ? reacquire_held_locks+0x420/0x420 ? reacquire_held_locks+0x420/0x420 kmalloc_order+0x3f/0xc0 kmalloc_order_trace+0x24/0x220 __kmalloc+0x41b/0x5a0 ? gcov_info_dup+0xfe/0x730 ? memcpy+0x73/0xa0 gcov_info_dup+0x176/0x730 gcov_event+0x88d/0xd30 gcov_module_notifier+0xe9/0x100 notifier_call_chain+0xeb/0x170 blocking_notifier_call_chain+0x75/0xc0 __x64_sys_delete_module+0x326/0x5a0 ? do_init_module+0x810/0x810 ? syscall_enter_from_user_mode+0x40/0x420 ? trace_hardirqs_on+0x45/0xb0 ? syscall_enter_from_user_mode+0x40/0x420 do_syscall_64+0x45/0x70 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f521f7c531b Code: 73 01 c3 48 8b 0d 7d 0b 0c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa b8 b0 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 4d 0b 0c 00 f7 d8 64 89 01 48 RSP: 002b:00007ffe1bd4af48 EFLAGS: 00000206 ORIG_RAX: 00000000000000b0 RAX: ffffffffffffffda RBX: 0000561a3eae0910 RCX: 00007f521f7c531b RDX: 0000000000000000 RSI: 0000000000000800 RDI: 0000561a3eae0978 RBP: 0000561a3eae0910 R08: 1999999999999999 R09: 0000000000000000 R10: 00007f521f839ac0 R11: 0000000000000206 R12: 0000000000000000 R13: 0000561a3eae0978 R14: 0000000000000000 R15: 0000561a3eae84d0 irq event stamp: 326464 hardirqs last enabled at (326463): [] _raw_spin_unlock_irqrestore+0x8e/0xb0 hardirqs last disabled at (326464): [] _raw_spin_lock_irqsave+0x34/0xa0 hardirqs last disabled at (326464): [] _raw_spin_lock_irqsave+0x34/0xa0 softirqs last enabled at (320794): [] __do_softirq+0x931/0xbc4 softirqs last disabled at (320789): [] asm_call_on_stack+0xf/0x20 ---[ end trace 065ea9cc2ba144a6 ]--- [3] https://bugzilla.kernel.org/show_bug.cgi?id=208885#c1 Cc: Colin Ian King Signed-off-by: Leon Romanovsky --- I have a strong feeling that this solution is not correct, but don't know how to do it right. The problem exists and reproducable in seconds. --- kernel/gcov/gcc_4_7.c | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-) diff --git a/kernel/gcov/gcc_4_7.c b/kernel/gcov/gcc_4_7.c index 908fdf5098c3..357ef839cdd3 100644 --- a/kernel/gcov/gcc_4_7.c +++ b/kernel/gcov/gcc_4_7.c @@ -275,20 +275,23 @@ struct gcov_info *gcov_info_dup(struct gcov_info *info) size_t fi_size; /* function info size */ size_t cv_size; /* counter values size */ - dup = kmemdup(info, sizeof(*dup), GFP_KERNEL); + dup = kzalloc(sizeof(*dup), GFP_KERNEL); if (!dup) return NULL; - dup->next = NULL; - dup->filename = NULL; - dup->functions = NULL; + dup->version = info->version; + dup->stamp = info->stamp; + for (fi_idx = 0; i < GCOV_COUNTERS; i++) + dup->merge[i] = info->merge[i]; + dup->n_functions = info->n_functions; - dup->filename = kstrdup(info->filename, GFP_KERNEL); + dup->filename = kstrdup_const(info->filename, GFP_KERNEL); if (!dup->filename) goto err_free; - dup->functions = kcalloc(info->n_functions, - sizeof(struct gcov_fn_info *), GFP_KERNEL); + dup->functions = + kcalloc(info->n_functions, sizeof(struct gcov_fn_info *), + GFP_KERNEL | __GFP_NOWARN); if (!dup->functions) goto err_free; @@ -359,7 +362,7 @@ void gcov_info_free(struct gcov_info *info) free_info: kfree(info->functions); - kfree(info->filename); + kfree_const(info->filename); kfree(info); } -- 2.26.2