From: Ingo Molnar <mingo@kernel.org>
To: linux-kernel@vger.kernel.org
Cc: Dave Hansen <dave.hansen@linux.intel.com>,
Andy Lutomirski <luto@amacapital.net>,
Thomas Gleixner <tglx@linutronix.de>,
"H . Peter Anvin" <hpa@zytor.com>,
Peter Zijlstra <peterz@infradead.org>,
Borislav Petkov <bp@alien8.de>,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: [PATCH 11/21] x86/dumpstack: Handle stack overflow on all stacks
Date: Mon, 27 Nov 2017 11:45:19 +0100 [thread overview]
Message-ID: <20171127104529.12435-12-mingo@kernel.org> (raw)
In-Reply-To: <20171127104529.12435-1-mingo@kernel.org>
From: Andy Lutomirski <luto@kernel.org>
We currently special-case stack overflow on the task stack. We're
going to start putting special stacks in the fixmap with a custom
layout, so they'll have guard pages, too. Teach the unwinder to be
able to unwind an overflow of any of the stacks.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Link: https://lkml.kernel.org/r/5454bb325cb30a70457a47b50f22317be65eba7d.1511497875.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/kernel/dumpstack.c | 24 ++++++++++++++----------
1 file changed, 14 insertions(+), 10 deletions(-)
diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c
index a49d3c86d324..de3083a1f820 100644
--- a/arch/x86/kernel/dumpstack.c
+++ b/arch/x86/kernel/dumpstack.c
@@ -112,24 +112,28 @@ void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
* - task stack
* - interrupt stack
* - HW exception stacks (double fault, nmi, debug, mce)
+ * - SYSENTER stack
*
- * x86-32 can have up to three stacks:
+ * x86-32 can have up to four stacks:
* - task stack
* - softirq stack
* - hardirq stack
+ * - SYSENTER stack
*/
for (regs = NULL; stack; stack = PTR_ALIGN(stack_info.next_sp, sizeof(long))) {
const char *stack_name;
- /*
- * If we overflowed the task stack into a guard page, jump back
- * to the bottom of the usable stack.
- */
- if (task_stack_page(task) - (void *)stack < PAGE_SIZE)
- stack = task_stack_page(task);
-
- if (get_stack_info(stack, task, &stack_info, &visit_mask))
- break;
+ if (get_stack_info(stack, task, &stack_info, &visit_mask)) {
+ /*
+ * We weren't on a valid stack. It's possible that
+ * we overflowed a valid stack into a guard page.
+ * See if the next page up is valid so that we can
+ * generate some kind of backtrace if this happens.
+ */
+ stack = (unsigned long *)PAGE_ALIGN((unsigned long)stack);
+ if (get_stack_info(stack, task, &stack_info, &visit_mask))
+ break;
+ }
stack_name = stack_type_name(stack_info.type);
if (stack_name)
--
2.14.1
next prev parent reply other threads:[~2017-11-27 10:49 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-27 10:45 [PATCH 00/21] Preparatory patches for x86 KAISER support Ingo Molnar
2017-11-27 10:45 ` [PATCH 01/21] x86/unwinder/orc: Don't bail on stack overflow Ingo Molnar
2017-11-27 14:47 ` Borislav Petkov
2017-11-27 10:45 ` [PATCH 02/21] x86/unwinder: Handle stack overflows more gracefully Ingo Molnar
2017-11-27 17:36 ` Borislav Petkov
2017-11-28 4:55 ` Josh Poimboeuf
2017-11-27 10:45 ` [PATCH 03/21] x86/irq: Remove an old outdated comment about context tracking races Ingo Molnar
2017-11-27 10:45 ` [PATCH 04/21] x86/irq/64: Print the offending IP in the stack overflow warning Ingo Molnar
2017-11-27 10:45 ` [PATCH 05/21] x86/entry/64: Allocate and enable the SYSENTER stack Ingo Molnar
2017-11-27 10:45 ` [PATCH 06/21] x86/dumpstack: Add get_stack_info() support for " Ingo Molnar
2017-11-27 10:45 ` [PATCH 07/21] x86/entry/gdt: Put per-CPU GDT remaps in ascending order Ingo Molnar
2017-11-27 10:45 ` [PATCH 08/21] x86/mm/fixmap: Generalize the GDT fixmap mechanism, introduce 'struct cpu_entry_area' Ingo Molnar
2017-11-27 10:45 ` [PATCH 09/21] x86/kasan/64: Teach KASAN about the cpu_entry_area Ingo Molnar
2017-11-27 10:45 ` [PATCH 10/21] x86/entry: Fix assumptions that the HW TSS is at the beginning of cpu_tss Ingo Molnar
2017-11-27 10:45 ` Ingo Molnar [this message]
2017-11-27 19:26 ` [PATCH 11/21] x86/dumpstack: Handle stack overflow on all stacks Linus Torvalds
2017-11-28 4:29 ` Josh Poimboeuf
2017-11-28 5:29 ` Andy Lutomirski
2017-11-28 18:15 ` Josh Poimboeuf
2017-11-27 10:45 ` [PATCH 12/21] x86/entry: Move SYSENTER_stack to the beginning of struct tss_struct Ingo Molnar
2017-11-27 10:45 ` [PATCH 13/21] x86/entry: Remap the TSS into the CPU entry area Ingo Molnar
2017-11-27 10:45 ` [PATCH 14/21] x86/entry/64: Separate cpu_current_top_of_stack from TSS.sp0 Ingo Molnar
2017-11-27 10:45 ` [PATCH 15/21] x86/espfix/64: Stop assuming that pt_regs is on the entry stack Ingo Molnar
2017-11-27 10:45 ` [PATCH 16/21] x86/entry/64: Use a per-CPU trampoline stack for IDT entries Ingo Molnar
2017-12-01 17:06 ` Dave Hansen
2017-12-01 17:44 ` Andy Lutomirski
2017-12-01 21:21 ` Dave Hansen
2017-12-01 21:59 ` Andy Lutomirski
2017-12-02 6:41 ` Kevin Easton
2017-11-27 10:45 ` [PATCH 17/21] x86/entry/64: Return to userspace from the trampoline stack Ingo Molnar
2017-11-27 10:45 ` [PATCH 18/21] x86/entry/64: Create a per-CPU SYSCALL entry trampoline Ingo Molnar
2017-11-27 10:45 ` [PATCH 19/21] x86/entry/64: Move the IST stacks into 'struct cpu_entry_area' Ingo Molnar
2017-11-27 10:45 ` [PATCH 20/21] x86/entry/64: Remove the SYSENTER stack canary Ingo Molnar
2017-11-27 10:45 ` [PATCH 21/21] x86/entry: Clean up the SYSENTER_stack code Ingo Molnar
2017-12-01 17:59 ` Borislav Petkov
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