Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758243AbdLVJk6 (ORCPT ); Fri, 22 Dec 2017 04:40:58 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:38722 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933764AbdLVJCA (ORCPT ); Fri, 22 Dec 2017 04:02:00 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Andy Lutomirski , Thomas Gleixner , Borislav Petkov , Boris Ostrovsky , Borislav Petkov , Borislav Petkov , Brian Gerst , Dave Hansen , Dave Hansen , David Laight , Denys Vlasenko , Eduardo Valentin , "H. Peter Anvin" , Josh Poimboeuf , Juergen Gross , Linus Torvalds , Peter Zijlstra , Rik van Riel , Will Deacon , aliguori@amazon.com, daniel.gruss@iaik.tugraz.at, hughd@google.com, keescook@google.com, Ingo Molnar Subject: [PATCH 4.14 080/159] x86/dumpstack: Add get_stack_info() support for the SYSENTER stack Date: Fri, 22 Dec 2017 09:46:05 +0100 Message-Id: <20171222084628.079948716@linuxfoundation.org> X-Mailer: git-send-email 2.15.1 In-Reply-To: <20171222084623.668990192@linuxfoundation.org> References: <20171222084623.668990192@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5201 Lines: 169 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Andy Lutomirski commit 33a2f1a6c4d7c0a02d1c006fb0379cc5ca3b96bb upstream. get_stack_info() doesn't currently know about the SYSENTER stack, so unwinding will fail if we entered the kernel on the SYSENTER stack and haven't fully switched off. Teach get_stack_info() about the SYSENTER stack. With future patches applied that run part of the entry code on the SYSENTER stack and introduce an intentional BUG(), I would get: PANIC: double fault, error_code: 0x0 ... RIP: 0010:do_error_trap+0x33/0x1c0 ... Call Trace: Code: ... With this patch, I get: PANIC: double fault, error_code: 0x0 ... Call Trace: ? async_page_fault+0x36/0x60 ? invalid_op+0x22/0x40 ? async_page_fault+0x36/0x60 ? sync_regs+0x3c/0x40 ? sync_regs+0x2e/0x40 ? error_entry+0x6c/0xd0 ? async_page_fault+0x36/0x60 Code: ... which is a lot more informative. Signed-off-by: Andy Lutomirski Signed-off-by: Thomas Gleixner Reviewed-by: Borislav Petkov Cc: Boris Ostrovsky Cc: Borislav Petkov Cc: Borislav Petkov Cc: Brian Gerst Cc: Dave Hansen Cc: Dave Hansen Cc: David Laight Cc: Denys Vlasenko Cc: Eduardo Valentin Cc: Greg KH Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Juergen Gross Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Rik van Riel Cc: Will Deacon Cc: aliguori@amazon.com Cc: daniel.gruss@iaik.tugraz.at Cc: hughd@google.com Cc: keescook@google.com Link: https://lkml.kernel.org/r/20171204150605.392711508@linutronix.de Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman diff --git a/arch/x86/include/asm/stacktrace.h b/arch/x86/include/asm/stacktrace.h index 8da111b3c342..f8062bfd43a0 100644 --- a/arch/x86/include/asm/stacktrace.h +++ b/arch/x86/include/asm/stacktrace.h @@ -16,6 +16,7 @@ enum stack_type { STACK_TYPE_TASK, STACK_TYPE_IRQ, STACK_TYPE_SOFTIRQ, + STACK_TYPE_SYSENTER, STACK_TYPE_EXCEPTION, STACK_TYPE_EXCEPTION_LAST = STACK_TYPE_EXCEPTION + N_EXCEPTION_STACKS-1, }; @@ -28,6 +29,8 @@ struct stack_info { bool in_task_stack(unsigned long *stack, struct task_struct *task, struct stack_info *info); +bool in_sysenter_stack(unsigned long *stack, struct stack_info *info); + int get_stack_info(unsigned long *stack, struct task_struct *task, struct stack_info *info, unsigned long *visit_mask); diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c index 0bc95be5c638..a33a1373a252 100644 --- a/arch/x86/kernel/dumpstack.c +++ b/arch/x86/kernel/dumpstack.c @@ -43,6 +43,25 @@ bool in_task_stack(unsigned long *stack, struct task_struct *task, return true; } +bool in_sysenter_stack(unsigned long *stack, struct stack_info *info) +{ + struct tss_struct *tss = this_cpu_ptr(&cpu_tss); + + /* Treat the canary as part of the stack for unwinding purposes. */ + void *begin = &tss->SYSENTER_stack_canary; + void *end = (void *)&tss->SYSENTER_stack + sizeof(tss->SYSENTER_stack); + + if ((void *)stack < begin || (void *)stack >= end) + return false; + + info->type = STACK_TYPE_SYSENTER; + info->begin = begin; + info->end = end; + info->next_sp = NULL; + + return true; +} + static void printk_stack_address(unsigned long address, int reliable, char *log_lvl) { diff --git a/arch/x86/kernel/dumpstack_32.c b/arch/x86/kernel/dumpstack_32.c index daefae83a3aa..5ff13a6b3680 100644 --- a/arch/x86/kernel/dumpstack_32.c +++ b/arch/x86/kernel/dumpstack_32.c @@ -26,6 +26,9 @@ const char *stack_type_name(enum stack_type type) if (type == STACK_TYPE_SOFTIRQ) return "SOFTIRQ"; + if (type == STACK_TYPE_SYSENTER) + return "SYSENTER"; + return NULL; } @@ -93,6 +96,9 @@ int get_stack_info(unsigned long *stack, struct task_struct *task, if (task != current) goto unknown; + if (in_sysenter_stack(stack, info)) + goto recursion_check; + if (in_hardirq_stack(stack, info)) goto recursion_check; diff --git a/arch/x86/kernel/dumpstack_64.c b/arch/x86/kernel/dumpstack_64.c index 88ce2ffdb110..abc828f8c297 100644 --- a/arch/x86/kernel/dumpstack_64.c +++ b/arch/x86/kernel/dumpstack_64.c @@ -37,6 +37,9 @@ const char *stack_type_name(enum stack_type type) if (type == STACK_TYPE_IRQ) return "IRQ"; + if (type == STACK_TYPE_SYSENTER) + return "SYSENTER"; + if (type >= STACK_TYPE_EXCEPTION && type <= STACK_TYPE_EXCEPTION_LAST) return exception_stack_names[type - STACK_TYPE_EXCEPTION]; @@ -115,6 +118,9 @@ int get_stack_info(unsigned long *stack, struct task_struct *task, if (in_irq_stack(stack, info)) goto recursion_check; + if (in_sysenter_stack(stack, info)) + goto recursion_check; + goto unknown; recursion_check: