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From: Andy Lutomirski <luto@kernel.org>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Alexey Dobriyan <adobriyan@gmail.com>,
	"H. Peter Anvin" <h.peter.anvin@intel.com>,
	kernel test robot <xiaolong.ye@intel.com>,
	Ingo Molnar <mingo@kernel.org>,
	Andrew Lutomirski <luto@kernel.org>,
	Borislav Petkov <bp@alien8.de>, Brian Gerst <brgerst@gmail.com>,
	Denys Vlasenko <dvlasenk@redhat.com>,
	Josh Poimboeuf <jpoimboe@redhat.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Peter Zijlstra <peterz@infradead.org>,
	LKML <linux-kernel@vger.kernel.org>,
	"H. Peter Anvin" <hpa@zytor.com>,
	tipbuild@zytor.com, LKP <lkp@01.org>
Subject: Re: [lkp-robot] [x86/asm] 51bad67ffb: int3:#[##]
Date: Tue, 15 May 2018 15:29:12 -0700	[thread overview]
Message-ID: <CALCETrWjMdTn8OyKgaydjK12sP8XKHtuXonEVnVHFPQ=jUtQLA@mail.gmail.com> (raw)
In-Reply-To: <alpine.DEB.2.21.1805160009230.1605@nanos.tec.linutronix.de>

On Tue, May 15, 2018 at 3:25 PM Thomas Gleixner <tglx@linutronix.de> wrote:

> On Wed, 16 May 2018, Alexey Dobriyan wrote:

> --- a/arch/x86/entry/entry_32.S
> +++ b/arch/x86/entry/entry_32.S
> @@ -338,6 +338,11 @@ END(ret_from_fork)
>          cmpl    $USER_RPL, %eax
>          jb      resume_kernel                   # not returning to v8086
or userspace

> +       /*
> +        * Jump over the alignment padding which is filled with int3
instructions
> +        */
> +       jmp     resume_userspace
> +
>   ENTRY(resume_userspace)

The problem is already solved, but NAK to this concept.  If we're going to
make ENTRY supply int3 alignment, then we need to avoid using ENTRY if we
fall through.  Jumping over the alignment is just silly.  The macro we
should use is GLOBAL.

WARNING: multiple messages have this Message-ID (diff)
From: Andy Lutomirski <luto@kernel.org>
To: lkp@lists.01.org
Subject: Re: [lkp-robot] [x86/asm] 51bad67ffb: int3:#[##]
Date: Tue, 15 May 2018 15:29:12 -0700	[thread overview]
Message-ID: <CALCETrWjMdTn8OyKgaydjK12sP8XKHtuXonEVnVHFPQ=jUtQLA@mail.gmail.com> (raw)
In-Reply-To: <alpine.DEB.2.21.1805160009230.1605@nanos.tec.linutronix.de>

[-- Attachment #1: Type: text/plain, Size: 803 bytes --]

On Tue, May 15, 2018 at 3:25 PM Thomas Gleixner <tglx@linutronix.de> wrote:

> On Wed, 16 May 2018, Alexey Dobriyan wrote:

> --- a/arch/x86/entry/entry_32.S
> +++ b/arch/x86/entry/entry_32.S
> @@ -338,6 +338,11 @@ END(ret_from_fork)
>          cmpl    $USER_RPL, %eax
>          jb      resume_kernel                   # not returning to v8086
or userspace

> +       /*
> +        * Jump over the alignment padding which is filled with int3
instructions
> +        */
> +       jmp     resume_userspace
> +
>   ENTRY(resume_userspace)

The problem is already solved, but NAK to this concept.  If we're going to
make ENTRY supply int3 alignment, then we need to avoid using ENTRY if we
fall through.  Jumping over the alignment is just silly.  The macro we
should use is GLOBAL.

  reply	other threads:[~2018-05-15 22:29 UTC|newest]

Thread overview: 61+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-15  8:00 [lkp-robot] [x86/asm] 51bad67ffb: int3:#[##] kernel test robot
2018-05-15  8:00 ` kernel test robot
2018-05-15 21:07 ` Alexey Dobriyan
2018-05-15 21:07   ` Alexey Dobriyan
2018-05-15 21:25   ` Anvin, H Peter
2018-05-15 21:43     ` Alexey Dobriyan
2018-05-15 21:43       ` Alexey Dobriyan
2018-05-15 22:22       ` Josh Poimboeuf
2018-05-15 22:22         ` Josh Poimboeuf
2018-05-15 22:26         ` Thomas Gleixner
2018-05-15 22:26           ` Thomas Gleixner
2018-05-15 22:28         ` Linus Torvalds
2018-05-15 22:28           ` Linus Torvalds
2018-05-15 22:43           ` Josh Poimboeuf
2018-05-15 22:43             ` Josh Poimboeuf
2018-05-15 22:52             ` Linus Torvalds
2018-05-15 22:52               ` Linus Torvalds
2018-05-15 23:05               ` Linus Torvalds
2018-05-15 23:05                 ` Linus Torvalds
2018-05-16  3:30                 ` Josh Poimboeuf
2018-05-16  3:30                   ` Josh Poimboeuf
2018-05-17 13:49                   ` [PATCH] objtool: Detect assembly code falling through to INT3 padding Josh Poimboeuf
2018-05-17 13:49                     ` Josh Poimboeuf
2018-05-17 14:01                     ` Peter Zijlstra
2018-05-17 14:01                       ` Peter Zijlstra
2018-05-18  7:24                       ` Ingo Molnar
2018-05-18  7:24                         ` Ingo Molnar
2018-05-18  7:18                     ` Ingo Molnar
2018-05-18  7:18                       ` Ingo Molnar
2018-05-18  7:27                       ` H. Peter Anvin
2018-05-18 16:06                         ` Borislav Petkov
2018-05-18 16:06                           ` Borislav Petkov
2018-05-18  7:27                       ` Ingo Molnar
2018-05-18  7:27                         ` Ingo Molnar
2018-05-18 17:51                       ` Alexey Dobriyan
2018-05-18 17:51                         ` Alexey Dobriyan
2018-05-19  8:18                         ` hpa
2018-05-19  7:00                 ` "interesting" entry in hibernation code was Re: [lkp-robot] [x86/asm] 51bad67ffb: int3:#[##] Pavel Machek
2018-05-19  7:00                   ` Pavel Machek
2018-05-19  8:35                   ` Rafael J. Wysocki
2018-05-19  8:35                     ` Rafael J. Wysocki
2018-05-18  7:15               ` Ingo Molnar
2018-05-18  7:15                 ` Ingo Molnar
2018-05-15 22:25       ` Thomas Gleixner
2018-05-15 22:25         ` Thomas Gleixner
2018-05-15 22:29         ` Andy Lutomirski [this message]
2018-05-15 22:29           ` Andy Lutomirski
2018-05-15 22:27       ` Linus Torvalds
2018-05-15 22:27         ` Linus Torvalds
2018-05-15 22:50         ` Alexey Dobriyan
2018-05-15 22:50           ` Alexey Dobriyan
2018-05-15 22:58           ` [PATCH v2] x86/asm: Pad assembly functions with INT3 instructions Alexey Dobriyan
2018-05-15 22:58             ` Alexey Dobriyan
2018-05-15 23:28             ` Linus Torvalds
2018-05-15 23:28               ` Linus Torvalds
2018-05-18  7:36             ` Ingo Molnar
2018-05-18  7:36               ` Ingo Molnar
2018-05-18 13:02               ` Josh Poimboeuf
2018-05-18 13:02                 ` Josh Poimboeuf
2018-05-18 17:34                 ` Alexey Dobriyan
2018-05-18 17:34                   ` Alexey Dobriyan

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