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From: Thomas Gleixner <tglx@linutronix.de>
To: Ingo Molnar <mingo@kernel.org>
Cc: Andrei Vagin <avagin@virtuozzo.com>,
	tip-bot for Jacob Shin <tipbot@zytor.com>,
	Cyrill Gorcunov <gorcunov@openvz.org>,
	linux-tip-commits@vger.kernel.org, luto@kernel.org,
	peterz@infradead.org, rostedt@goodmis.org,
	linux-kernel@vger.kernel.org, hpa@zytor.com, brgerst@gmail.com,
	jpoimboe@redhat.com, bp@alien8.de, torvalds@linux-foundation.org,
	dvlasenk@redhat.com
Subject: Re: [PATCH] x86/idt: Fix the X86_TRAP_BP gate
Date: Fri, 1 Sep 2017 10:59:39 +0200 (CEST)	[thread overview]
Message-ID: <alpine.DEB.2.20.1709011057180.1857@nanos> (raw)
In-Reply-To: <20170901082630.xvyi5bwk6etmppqc@gmail.com>

On Fri, 1 Sep 2017, Ingo Molnar wrote:
> Subject: x86/idt: Fix the X86_TRAP_BP gate
> From: Ingo Molnar <mingo@kernel.org>
> 
> Andrei Vagin reported a CRIU regression and bisected it back to:
> 
>   90f6225fba0c ("x86/idt: Move IST stack based traps to table init")
> 
> This table init conversion loses the system-gate property of X86_TRAP_BP
> and erroneously moves it from DPL3 to DPL0.

Duh, yes. Thanks for spotting it.

> Fix it.
> 
> Reported-by: Andrei Vagin <avagin@virtuozzo.com>
> Cc: Linus Torvalds <torvalds@linux-foundation.org>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Signed-off-by: Ingo Molnar <mingo@kernel.org>
> ---
> arch/x86/kernel/idt.c | 6 +++++-
>  arch/x86/kernel/idt.c |    6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> Index: tip/arch/x86/kernel/idt.c
> ===================================================================
> --- tip.orig/arch/x86/kernel/idt.c
> +++ tip/arch/x86/kernel/idt.c
> @@ -44,6 +44,10 @@ struct idt_data {
>  #define ISTG(_vector, _addr, _ist)			\
>  	G(_vector, _addr, _ist, GATE_INTERRUPT, DPL0, __KERNEL_CS)
>  
> +/* System interrupt gate with interrupt stack */
> +#define SISTG(_vector, _addr, _ist)			\
> +	G(_vector, _addr, _ist, GATE_INTERRUPT, DPL3, __KERNEL_CS)
> +
>  /* Task gate */
>  #define TSKG(_vector, _gdt)				\
>  	G(_vector, NULL, DEFAULT_STACK, GATE_TASK, DPL0, _gdt << 3)
> @@ -181,7 +185,7 @@ gate_desc debug_idt_table[IDT_ENTRIES] _
>  static const __initdata struct idt_data ist_idts[] = {
>  	ISTG(X86_TRAP_DB,	debug,		DEBUG_STACK),
>  	ISTG(X86_TRAP_NMI,	nmi,		NMI_STACK),
> -	ISTG(X86_TRAP_BP,	int3,		DEBUG_STACK),
> +	SISTG(X86_TRAP_BP,	int3,		DEBUG_STACK),
>  	ISTG(X86_TRAP_DF,	double_fault,	DOUBLEFAULT_STACK),
>  #ifdef CONFIG_X86_MCE
>  	ISTG(X86_TRAP_MC,	&machine_check,	MCE_STACK),
> 

  reply	other threads:[~2017-09-01  9:00 UTC|newest]

Thread overview: 95+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-08-28  6:47 [patch V3 00/44] x86: Cleanup IDT code Thomas Gleixner
2017-08-28  6:47 ` [patch V3 01/44] x86/irq: Remove vector_used_by_percpu_irq() Thomas Gleixner
2017-08-29 11:04   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 02/44] x86/irq: Unexport used_vectors Thomas Gleixner
2017-08-29 11:04   ` [tip:x86/apic] x86/irq: Unexport used_vectors[] tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 03/44] x86/irq: Get rid of the first_system_vector bogisity Thomas Gleixner
2017-08-29 11:04   ` [tip:x86/apic] x86/irq: Get rid of the 'first_system_vector' indirection bogosity tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 04/44] x86/irq: Remove duplicated used_vectors definition Thomas Gleixner
2017-08-29 11:05   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 05/44] x86/boot: Move EISA setup to a proper place Thomas Gleixner
2017-08-29 11:05   ` [tip:x86/apic] x86/boot: Move EISA setup to a separate file tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 06/44] x86/tracing: Introduce a static key for exception tracing Thomas Gleixner
2017-08-29 11:06   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 07/44] x86/traps: Simplify pagefault tracing logic Thomas Gleixner
2017-08-29 11:06   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 08/44] x86/apic: Remove the duplicated tracing version of local_timer_interrupt Thomas Gleixner
2017-08-29 11:07   ` [tip:x86/apic] x86/apic: Remove the duplicated tracing version of local_timer_interrupt() tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 09/44] x86/apic: Use this_cpu_ptr in local_timer_interrupt Thomas Gleixner
2017-08-29 11:07   ` [tip:x86/apic] x86/apic: Use this_cpu_ptr() in local_timer_interrupt() tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 10/44] x86/irq: Get rid of duplicated trace_x86_platform_ipi() code Thomas Gleixner
2017-08-29 11:07   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 11/44] x86/apic: Remove the duplicated tracing versions of interrupts Thomas Gleixner
2017-08-29 11:08   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 12/44] x86/irqwork: Get rid of duplicated tracing interrupt code Thomas Gleixner
2017-08-29 11:08   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 13/44] x86/mce: Remove " Thomas Gleixner
2017-08-29 11:08   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 14/44] x86/smp: Remove pointless duplicated " Thomas Gleixner
2017-08-29 11:09   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 15/44] x86/smp: Use static key for reschedule interrupt tracing Thomas Gleixner
2017-08-29 11:09   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 16/44] x86/idt: Remove tracing idt completely Thomas Gleixner
2017-08-29 11:10   ` [tip:x86/apic] x86/idt: Remove the tracing IDT completely tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 17/44] x86/idt: Cleanup the i386 low level entry macros Thomas Gleixner
2017-08-29 11:10   ` [tip:x86/apic] x86/idt: Clean up " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 18/44] x86/tracing: Disentangle pagefault and resched IPI tracing key Thomas Gleixner
2017-08-29 11:10   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 19/44] x86/ipi: Make platform IPI depend on APIC Thomas Gleixner
2017-08-29 11:11   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 20/44] x86/irq_work: Make it " Thomas Gleixner
2017-08-29 11:11   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 21/44] x86/tracing: Build tracepoints only when they are used Thomas Gleixner
2017-08-29 11:12   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 22/44] x86/idt: Unify gate_struct handling for 32/64bit Thomas Gleixner
2017-08-29 11:12   ` [tip:x86/apic] x86/idt: Unify gate_struct handling for 32/64-bit kernels tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 23/44] x86/percpu: Use static initializer for GDT entry Thomas Gleixner
2017-08-29 11:13   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 24/44] x86/fpu: Use bitfield accessors for desc_struct Thomas Gleixner
2017-08-29 11:13   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 25/44] x86: Replace access to desc_struct:a/b fields Thomas Gleixner
2017-08-29 11:13   ` [tip:x86/apic] x86/asm: " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 26/44] x86/gdt: Use bitfields for initialization Thomas Gleixner
2017-08-29 11:14   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 27/44] x86/ldttss: Cleanup 32bit descriptors Thomas Gleixner
2017-08-29 11:14   ` [tip:x86/apic] x86/ldttss: Clean up 32-bit descriptors tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 28/44] x86/idt: Create file for IDT related code Thomas Gleixner
2017-08-29 11:15   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 29/44] x86/idt: Move 32bit idt_descr to C code Thomas Gleixner
2017-08-29 11:15   ` [tip:x86/apic] x86/idt: Move 32-bit " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 30/44] x86/idt: Remove unused set_trap_gate() Thomas Gleixner
2017-08-29 11:16   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 31/44] x86/idt: Consolidate IDT invalidation Thomas Gleixner
2017-08-29 11:16   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 32/44] x86/idt: Move early IDT handler setup to IDT code Thomas Gleixner
2017-08-29 11:16   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 33/44] x86/idt: Move early IDT setup out of 32bit asm Thomas Gleixner
2017-08-29 11:17   ` [tip:x86/apic] x86/idt: Move early IDT setup out of 32-bit asm tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 34/44] x86/idt: Prepare for table based init Thomas Gleixner
2017-08-29 11:17   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 35/44] x86/idt: Switch early trap init to IDT tables Thomas Gleixner
2017-08-29 11:18   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 36/44] x86/idt: Move debug stack init to table based Thomas Gleixner
2017-08-29 11:18   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 37/44] x86/idt: Move ist stack based traps to table init Thomas Gleixner
2017-08-29 11:18   ` [tip:x86/apic] x86/idt: Move IST " tip-bot for Thomas Gleixner
2017-09-01  6:28     ` Andrei Vagin
2017-09-01  8:26       ` [PATCH] x86/idt: Fix the X86_TRAP_BP gate Ingo Molnar
2017-09-01  8:59         ` Thomas Gleixner [this message]
2017-09-01  9:09         ` [tip:x86/apic] " tip-bot for Ingo Molnar
2017-09-01 14:39         ` [PATCH] " Andrei Vagin
2017-08-28  6:47 ` [patch V3 38/44] x86/idt: Move regular trap init to tables Thomas Gleixner
2017-08-29 11:19   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 39/44] x86/idt: Move APIC gate initialization " Thomas Gleixner
2017-08-29 11:19   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 40/44] x86/idt: Move interrupt gate initialization to IDT code Thomas Gleixner
2017-08-29 11:20   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 41/44] x86/idt: Remove unused functions/inlines Thomas Gleixner
2017-08-29 11:20   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 42/44] x86/idt: Deinline setup functions Thomas Gleixner
2017-08-29 11:20   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 43/44] x86/idt: Simplify alloc_intr_gate Thomas Gleixner
2017-08-28 14:35   ` KY Srinivasan
2017-08-29 11:21   ` [tip:x86/apic] x86/idt: Simplify alloc_intr_gate() tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 44/44] x86/idt: Hide set_intr_gate() Thomas Gleixner
2017-08-29 11:21   ` [tip:x86/apic] " tip-bot for Thomas Gleixner

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