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From: Peter Zijlstra <peterz@infradead.org>
To: tglx@linutronix.de, luto@amacapital.net, peterz@infradead.org
Cc: linux-kernel@vger.kernel.org, x86@kernel.org,
	Lai Jiangshan <laijs@linux.alibaba.com>,
	sean.j.christopherson@intel.com, andrew.cooper3@citrix.com,
	daniel.thompson@linaro.org, a.darwish@linutronix.de,
	rostedt@goodmis.org, bigeasy@linutronix.de
Subject: [PATCH 03/14] x86/hw_breakpoint: Prevent data breakpoints on per_cpu cpu_tss_rw
Date: Fri, 29 May 2020 23:27:31 +0200	[thread overview]
Message-ID: <20200529213320.897976479@infradead.org> (raw)
In-Reply-To: 20200529212728.795169701@infradead.org

From: Lai Jiangshan <laijs@linux.alibaba.com>

cpu_tss_rw is not directly referenced by hardware, but
cpu_tss_rw is also used in CPU entry code, especially
when #DB shifts its stacks. If a data breakpoint is on
the cpu_tss_rw.x86_tss.ist[IST_INDEX_DB], it will cause
recursive #DB (and then #DF soon for #DB is generated
after the access, IST-shifting, is done).

Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200526014221.2119-4-laijs@linux.alibaba.com
---
 arch/x86/kernel/hw_breakpoint.c |    9 +++++++++
 1 file changed, 9 insertions(+)

--- a/arch/x86/kernel/hw_breakpoint.c
+++ b/arch/x86/kernel/hw_breakpoint.c
@@ -255,6 +255,15 @@ static inline bool within_cpu_entry(unsi
 		if (within_area(addr, end, (unsigned long)get_cpu_gdt_rw(cpu),
 				GDT_SIZE))
 			return true;
+
+		/*
+		 * cpu_tss_rw is not directly referenced by hardware, but
+		 * cpu_tss_rw is also used in CPU entry code,
+		 */
+		if (within_area(addr, end,
+				(unsigned long)&per_cpu(cpu_tss_rw, cpu),
+				sizeof(struct tss_struct)))
+			return true;
 	}
 
 	return false;



  parent reply	other threads:[~2020-05-29 21:37 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-29 21:27 [PATCH 00/14] x86/entry: disallow #DB more and x86/entry lockdep/nmi Peter Zijlstra
2020-05-29 21:27 ` [PATCH 01/14] x86/hw_breakpoint: Add within_area() to check data breakpoints Peter Zijlstra
2020-05-29 21:27 ` [PATCH 02/14] x86/hw_breakpoint: Prevent data breakpoints on direct GDT Peter Zijlstra
2020-05-30 12:45   ` Andrew Cooper
2020-05-30 15:15     ` Lai Jiangshan
2020-05-29 21:27 ` Peter Zijlstra [this message]
2020-05-29 21:27 ` [PATCH 04/14] x86/hw_breakpoint: Prevent data breakpoints on user_pcid_flush_mask Peter Zijlstra
2020-05-29 21:27 ` [PATCH 05/14] x86/entry: Introduce local_db_{save,restore}() Peter Zijlstra
2020-05-30  9:57   ` [tip: x86/entry] " tip-bot2 for Peter Zijlstra
2020-05-29 21:27 ` [PATCH 06/14] x86/entry, nmi: Disable #DB Peter Zijlstra
2020-05-30  9:57   ` [tip: x86/entry] " tip-bot2 for Peter Zijlstra
2020-05-29 21:27 ` [PATCH 07/14] x86/entry, mce: Disallow #DB during #MC Peter Zijlstra
2020-05-30  9:57   ` [tip: x86/entry] " tip-bot2 for Peter Zijlstra
2020-05-29 21:27 ` [PATCH 08/14] x86/entry: Optimize local_db_save() for virt Peter Zijlstra
2020-05-30  9:57   ` [tip: x86/entry] " tip-bot2 for Peter Zijlstra
2020-06-03  1:17   ` [PATCH 08/14] " Sean Christopherson
2020-05-29 21:27 ` [PATCH 09/14] x86/entry: Remove debug IDT frobbing Peter Zijlstra
2020-05-30  9:57   ` [tip: x86/entry] " tip-bot2 for Peter Zijlstra
2020-05-29 21:27 ` [PATCH 10/14] x86/entry: Remove DBn stacks Peter Zijlstra
2020-05-30  9:57   ` [tip: x86/entry] " tip-bot2 for Peter Zijlstra
2020-05-29 21:27 ` [PATCH 11/14] x86/entry: Clarify irq_{enter,exit}_rcu() Peter Zijlstra
2020-05-30  9:57   ` [tip: x86/entry] " tip-bot2 for Peter Zijlstra
2020-06-02 14:42   ` [PATCH 11/14] " Qian Cai
2020-06-02 14:42     ` Qian Cai
2020-06-02 15:05     ` Peter Zijlstra
2020-06-02 15:05       ` Peter Zijlstra
2020-06-02 18:47       ` Qian Cai
2020-06-02 18:47         ` Qian Cai
2020-06-03 17:50       ` [tip: x86/entry] x86/entry: Use __irq_exit_rcu() in irq_exit() tip-bot2 for Peter Zijlstra
2020-05-29 21:27 ` [PATCH 12/14] x86/entry: Rename trace_hardirqs_off_prepare() Peter Zijlstra
2020-05-30  9:57   ` [tip: x86/entry] " tip-bot2 for Peter Zijlstra
2020-05-29 21:27 ` [PATCH 13/14] lockdep: Prepare for NMI IRQ state tracking Peter Zijlstra
2020-05-29 22:14   ` Steven Rostedt
2020-05-29 22:25     ` Peter Zijlstra
2020-05-29 22:28       ` Steven Rostedt
2020-05-29 22:33       ` Peter Zijlstra
2020-06-02 20:00       ` Peter Zijlstra
2020-05-29 21:27 ` [PATCH 14/14] x86/entry: Fix NMI vs " Peter Zijlstra

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