From: Thomas Gleixner <tglx@linutronix.de> To: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Alexey Dobriyan <adobriyan@gmail.com>, "Anvin, H Peter" <h.peter.anvin@intel.com>, "Ye, Xiaolong" <xiaolong.ye@intel.com>, Ingo Molnar <mingo@kernel.org>, Andy Lutomirski <luto@kernel.org>, Borislav Petkov <bp@alien8.de>, Brian Gerst <brgerst@gmail.com>, Denys Vlasenko <dvlasenk@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" <tipbuild@zytor.com>, "lkp@01.org" <lkp@01.org> Subject: Re: [lkp-robot] [x86/asm] 51bad67ffb: int3:#[##] Date: Wed, 16 May 2018 00:26:45 +0200 (CEST) [thread overview] Message-ID: <alpine.DEB.2.21.1805160026060.1605@nanos.tec.linutronix.de> (raw) In-Reply-To: <20180515222211.ods5hzne46hozojq@treble> On Tue, 15 May 2018, Josh Poimboeuf wrote: > On Wed, May 16, 2018 at 12:43:37AM +0300, Alexey Dobriyan wrote: > > On Tue, May 15, 2018 at 09:25:53PM +0000, Anvin, H Peter wrote: > > > Why is that a problem? > > > Code: 00 00 00 eb e6 cc cc cc cc cc cc cc cc cc cc cc cc cc fa 8d b6 00 00 00 00 e8 5d e8 8f ff 8b 44 24 34 83 e0 03 83 f8 03 72 28 cc <cc> cc cc cc cc cc cc fa 8d b6 00 00 00 00 e8 3d e8 8f ff 89 e0 > > > > > > EIP: ret_from_intr+0xd/0x14 SS:ESP: 0068:8603bfb4 > > > > > > INT3 slipped through M586 => X86_ALIGNMENT_16 :-\ > > > > I could make the patch x86_64 only, but! > > > > It crashed into the middle of the padding. > > > > 796ef8fc <ret_from_intr>: > > 796ef8fc: 8b 44 24 34 mov eax,DWORD PTR [esp+0x34] > > 796ef900: 83 e0 03 and eax,0x3 > > 796ef903: 83 f8 03 cmp eax,0x3 > > 796ef906: 72 28 jb 796ef930 <resume_kernel> > > 796ef908: cc int3 > > 796ef909: cc <========> int3 > > 796ef90a: cc int3 > > 796ef90b: cc int3 > > 796ef90c: cc int3 > > 796ef90d: cc int3 > > 796ef90e: cc int3 > > 796ef90f: cc int3 > > The padding isn't needed there, and the resume_userspace symbol is never > used, so wouldn't this fix it? Gack. Right you are. I assumed that the ENTRY() is used without checking .... > > diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S > index bef8e2b202a8..9e56243c984c 100644 > --- a/arch/x86/entry/entry_32.S > +++ b/arch/x86/entry/entry_32.S > @@ -338,7 +338,6 @@ ret_from_intr: > cmpl $USER_RPL, %eax > jb resume_kernel # not returning to v8086 or userspace > > -ENTRY(resume_userspace) > DISABLE_INTERRUPTS(CLBR_ANY) > TRACE_IRQS_OFF > movl %esp, %eax >
WARNING: multiple messages have this Message-ID (diff)
From: Thomas Gleixner <tglx@linutronix.de> To: lkp@lists.01.org Subject: Re: [lkp-robot] [x86/asm] 51bad67ffb: int3:#[##] Date: Wed, 16 May 2018 00:26:45 +0200 [thread overview] Message-ID: <alpine.DEB.2.21.1805160026060.1605@nanos.tec.linutronix.de> (raw) In-Reply-To: <20180515222211.ods5hzne46hozojq@treble> [-- Attachment #1: Type: text/plain, Size: 1996 bytes --] On Tue, 15 May 2018, Josh Poimboeuf wrote: > On Wed, May 16, 2018 at 12:43:37AM +0300, Alexey Dobriyan wrote: > > On Tue, May 15, 2018 at 09:25:53PM +0000, Anvin, H Peter wrote: > > > Why is that a problem? > > > Code: 00 00 00 eb e6 cc cc cc cc cc cc cc cc cc cc cc cc cc fa 8d b6 00 00 00 00 e8 5d e8 8f ff 8b 44 24 34 83 e0 03 83 f8 03 72 28 cc <cc> cc cc cc cc cc cc fa 8d b6 00 00 00 00 e8 3d e8 8f ff 89 e0 > > > > > > EIP: ret_from_intr+0xd/0x14 SS:ESP: 0068:8603bfb4 > > > > > > INT3 slipped through M586 => X86_ALIGNMENT_16 :-\ > > > > I could make the patch x86_64 only, but! > > > > It crashed into the middle of the padding. > > > > 796ef8fc <ret_from_intr>: > > 796ef8fc: 8b 44 24 34 mov eax,DWORD PTR [esp+0x34] > > 796ef900: 83 e0 03 and eax,0x3 > > 796ef903: 83 f8 03 cmp eax,0x3 > > 796ef906: 72 28 jb 796ef930 <resume_kernel> > > 796ef908: cc int3 > > 796ef909: cc <========> int3 > > 796ef90a: cc int3 > > 796ef90b: cc int3 > > 796ef90c: cc int3 > > 796ef90d: cc int3 > > 796ef90e: cc int3 > > 796ef90f: cc int3 > > The padding isn't needed there, and the resume_userspace symbol is never > used, so wouldn't this fix it? Gack. Right you are. I assumed that the ENTRY() is used without checking .... > > diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S > index bef8e2b202a8..9e56243c984c 100644 > --- a/arch/x86/entry/entry_32.S > +++ b/arch/x86/entry/entry_32.S > @@ -338,7 +338,6 @@ ret_from_intr: > cmpl $USER_RPL, %eax > jb resume_kernel # not returning to v8086 or userspace > > -ENTRY(resume_userspace) > DISABLE_INTERRUPTS(CLBR_ANY) > TRACE_IRQS_OFF > movl %esp, %eax >
next prev parent reply other threads:[~2018-05-15 22:27 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 [this message] 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 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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