Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756010AbcK3XKR (ORCPT ); Wed, 30 Nov 2016 18:10:17 -0500 Received: from mx1.redhat.com ([209.132.183.28]:41712 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752346AbcK3XKO (ORCPT ); Wed, 30 Nov 2016 18:10:14 -0500 Date: Wed, 30 Nov 2016 17:10:11 -0600 From: Josh Poimboeuf To: "Rafael J. Wysocki" , Len Brown , Pavel Machek , linux-pm@vger.kernel.org Cc: linux-kernel@vger.kernel.org, peterz@infradead.org, mingo@kernel.org, luto@amacapital.net, Scott Bauer , x86@kernel.org, Andrey Ryabinin , Alexander Potapenko , Dmitry Vyukov , kasan-dev@googlegroups.com Subject: [PATCH] x86/suspend: fix false positive KASAN warning on suspend/resume Message-ID: <20161130231011.ofmbmevn3hqasetz@treble> References: <20161129181300.GA29095@sbauer-Z170X-UD5> <20161130183507.syv3cdpp3hzxi77k@treble> <20161130190217.GA2756@sbauer-Z170X-UD5> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20161130190217.GA2756@sbauer-Z170X-UD5> User-Agent: Mutt/1.6.0.1 (2016-04-01) X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.38]); Wed, 30 Nov 2016 23:10:14 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5446 Lines: 140 Resuming from a suspend operation is showing a KASAN false positive warning: BUG: KASAN: stack-out-of-bounds in unwind_get_return_address+0x11d/0x130 at addr ffff8803867d7878 Read of size 8 by task pm-suspend/7774 page:ffffea000e19f5c0 count:0 mapcount:0 mapping: (null) index:0x0 flags: 0x2ffff0000000000() page dumped because: kasan: bad access detected CPU: 0 PID: 7774 Comm: pm-suspend Tainted: G B 4.9.0-rc7+ #8 Hardware name: Gigabyte Technology Co., Ltd. Z170X-UD5/Z170X-UD5-CF, BIOS F5 03/07/2016 ffff8803867d7468 ffffffffb4c0d051 ffff8803867d7500 ffff8803867d7878 ffff8803867d74f0 ffffffffb45cbe34 ffffffffb4e64136 ffffffffb4510d42 ffff8803828c3f4c 0000000000000097 0000000041b58ab3 ffffffffb6192731 Call Trace: dump_stack+0x63/0x82 kasan_report_error+0x4b4/0x4e0 ? acpi_hw_read_port+0xd0/0x1ea ? kfree_const+0x22/0x30 ? acpi_hw_validate_io_request+0x1a6/0x1a6 __asan_report_load8_noabort+0x61/0x70 ? unwind_get_return_address+0x11d/0x130 unwind_get_return_address+0x11d/0x130 ? unwind_next_frame+0x97/0xf0 __save_stack_trace+0x92/0x100 save_stack_trace+0x1b/0x20 save_stack+0x46/0xd0 ? save_stack_trace+0x1b/0x20 ? save_stack+0x46/0xd0 ? kasan_kmalloc+0xad/0xe0 ? kasan_slab_alloc+0x12/0x20 ? acpi_hw_read+0x2b6/0x3aa ? acpi_hw_validate_register+0x20b/0x20b ? acpi_hw_write_port+0x72/0xc7 ? acpi_hw_write+0x11f/0x15f ? acpi_hw_read_multiple+0x19f/0x19f ? memcpy+0x45/0x50 ? acpi_hw_write_port+0x72/0xc7 ? acpi_hw_write+0x11f/0x15f ? acpi_hw_read_multiple+0x19f/0x19f ? kasan_unpoison_shadow+0x36/0x50 kasan_kmalloc+0xad/0xe0 kasan_slab_alloc+0x12/0x20 kmem_cache_alloc_trace+0xbc/0x1e0 ? acpi_get_sleep_type_data+0x9a/0x578 acpi_get_sleep_type_data+0x9a/0x578 acpi_hw_legacy_wake_prep+0x88/0x22c ? acpi_hw_legacy_sleep+0x3c7/0x3c7 ? acpi_write_bit_register+0x28d/0x2d3 ? acpi_read_bit_register+0x19b/0x19b acpi_hw_sleep_dispatch+0xb5/0xba acpi_leave_sleep_state_prep+0x17/0x19 acpi_suspend_enter+0x154/0x1e0 ? trace_suspend_resume+0xe8/0xe8 suspend_devices_and_enter+0xb09/0xdb0 ? printk+0xa8/0xd8 ? arch_suspend_enable_irqs+0x20/0x20 ? try_to_freeze_tasks+0x295/0x600 pm_suspend+0x6c9/0x780 ? finish_wait+0x1f0/0x1f0 ? suspend_devices_and_enter+0xdb0/0xdb0 state_store+0xa2/0x120 ? kobj_attr_show+0x60/0x60 kobj_attr_store+0x36/0x70 sysfs_kf_write+0x131/0x200 kernfs_fop_write+0x295/0x3f0 __vfs_write+0xef/0x760 ? handle_mm_fault+0x1346/0x35e0 ? do_iter_readv_writev+0x660/0x660 ? __pmd_alloc+0x310/0x310 ? do_lock_file_wait+0x1e0/0x1e0 ? apparmor_file_permission+0x18/0x20 ? security_file_permission+0x73/0x1c0 ? rw_verify_area+0xbd/0x2b0 vfs_write+0x149/0x4a0 SyS_write+0xd9/0x1c0 ? SyS_read+0x1c0/0x1c0 entry_SYSCALL_64_fastpath+0x1e/0xad Memory state around the buggy address: ffff8803867d7700: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff8803867d7780: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff8803867d7800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 f4 ^ ffff8803867d7880: f3 f3 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00 ffff8803867d7900: 00 00 00 f1 f1 f1 f1 04 f4 f4 f4 f3 f3 f3 f3 00 KASAN instrumentation poisons the stack when entering a function and unpoisons it when exiting the function. However, in the suspend path, some functions never return, so their stack never gets unpoisoned, resulting in stale KASAN shadow data which can cause false positive warnings like the one above. Reported-by: Scott Bauer Tested-by: Scott Bauer Signed-off-by: Josh Poimboeuf --- arch/x86/kernel/acpi/sleep.c | 3 +++ include/linux/kasan.h | 7 +++++++ 2 files changed, 10 insertions(+) diff --git a/arch/x86/kernel/acpi/sleep.c b/arch/x86/kernel/acpi/sleep.c index 4858733..62bd046 100644 --- a/arch/x86/kernel/acpi/sleep.c +++ b/arch/x86/kernel/acpi/sleep.c @@ -115,6 +115,9 @@ int x86_acpi_suspend_lowlevel(void) pause_graph_tracing(); do_suspend_lowlevel(); unpause_graph_tracing(); + + kasan_unpoison_stack_below_sp(); + return 0; } diff --git a/include/linux/kasan.h b/include/linux/kasan.h index 820c0ad..e0945d5 100644 --- a/include/linux/kasan.h +++ b/include/linux/kasan.h @@ -45,6 +45,12 @@ void kasan_unpoison_shadow(const void *address, size_t size); void kasan_unpoison_task_stack(struct task_struct *task); void kasan_unpoison_stack_above_sp_to(const void *watermark); +asmlinkage void kasan_unpoison_task_stack_below(const void *watermark); + +static inline void kasan_unpoison_stack_below_sp(void) +{ + kasan_unpoison_task_stack_below(__builtin_frame_address(0)); +} void kasan_alloc_pages(struct page *page, unsigned int order); void kasan_free_pages(struct page *page, unsigned int order); @@ -87,6 +93,7 @@ static inline void kasan_unpoison_shadow(const void *address, size_t size) {} static inline void kasan_unpoison_task_stack(struct task_struct *task) {} static inline void kasan_unpoison_stack_above_sp_to(const void *watermark) {} +static inline void kasan_unpoison_stack_below_sp(void) {} static inline void kasan_enable_current(void) {} static inline void kasan_disable_current(void) {} -- 2.7.4