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From: Dave Hansen <dave.hansen@intel.com>
To: Oleg Nesterov <oleg@redhat.com>, Borislav Petkov <bp@suse.de>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>,
	Andy Lutomirski <luto@amacapital.net>,
	Ingo Molnar <mingo@kernel.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Pekka Riikonen <priikone@iki.fi>, Rik van Riel <riel@redhat.com>,
	Suresh Siddha <sbsiddha@gmail.com>,
	LKML <linux-kernel@vger.kernel.org>,
	"Yu, Fenghua" <fenghua.yu@intel.com>
Subject: Re: Oops with tip/x86/fpu
Date: Thu, 05 Mar 2015 10:41:08 -0800	[thread overview]
Message-ID: <54F8A344.7070308@intel.com> (raw)
In-Reply-To: <20150305182203.GA4203@redhat.com>

On 03/05/2015 10:22 AM, Oleg Nesterov wrote:
> On 03/05, Oleg Nesterov wrote:
>>
>> I _think_ that the difference is that eager_fpu_init()->xrstor_state()
>> was called before apply_alternatives(), so it used XRSTOR.
>>
>> Note also that (before this commit) restore_fpu_checking() was almost
>> never called right after init_fpu(). If use_eager_fpu() == T.
>>
>> After this commit the first xrstor_state() uses XRSTORS. And that is
>> how (I think) 'noxsaves' makes the difference.
>>
>>
>> So. I can be easily wrong, but so far I _think_ that this commit disclosed
>> another problem. And even if I am wrong and this commit is buggy, we need
>> to understand why ;)
>>
>> I'll try to think about debugging patch, I can't reproduce this problem
>> on my machine...
> 
> Dave. could please run the test-case below?
> 
> Without 'noxsaves', and without my commit.
> 
> Please compile it "cc --static -m32 -Wall T.c". In case you do not have
> the 32-bit libs, I also attached the static binary.
> 
> It should trigger another known problem which I was going to fix later,
> math_state_restore() wrongly does cli/sti. Please ignore the "sleeping
> function called from invalid context" warning in dmesg.
> 
> Does it trigger something else on your machine?

Triggers this:

> [  125.384358] general protection fault: 0000 [#1] SMP 
> [  125.390033] Modules linked in:
> [  125.393521] CPU: 0 PID: 1417 Comm: oleg-test Not tainted 3.19.0-00428-g4b2e762 #774
> [  125.402222] Hardware name: Intel Corporation Skylake Client platform/Skylake Y LPDDR3 RVP3, BIOS SKLSE2P1.86C.X062.R00.1411270820 11/27/2014
> [  125.416537] task: ffff88009af0e100 ti: ffff88009bf24000 task.ti: ffff88009bf24000
> [  125.425034] RIP: 0010:[<ffffffff810556cb>]  [<ffffffff810556cb>] math_state_restore+0x8b/0x1c0
> [  125.434839] RSP: 0000:ffff88009bf27e08  EFLAGS: 00010046
> [  125.440873] RAX: 00000000ffffffff RBX: ffff88009af0e100 RCX: 0000000000000000
> [  125.448972] RDX: 00000000ffffffff RSI: 0000000000000000 RDI: ffff880148020780
> [  125.457073] RBP: ffff88009bf27e18 R08: 0000000000000000 R09: ffff880148020780
> [  125.465175] R10: 0000000000000001 R11: ffffffff817a0829 R12: ffff88009af0e100
> [  125.473274] R13: 0000000000000071 R14: 0000000000000200 R15: 0000000000000000
> [  125.481367] FS:  0000000000000000(0003) GS:ffff88014e400000(0063) knlGS:00000000089ea840
> [  125.490551] CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
> [  125.497075] CR2: 0000000000000071 CR3: 000000007f8ce000 CR4: 00000000003407f0
> [  125.505177] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> [  125.513283] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> [  125.521381] Stack:
> [  125.523664]  0000000000000000 00000000ffffffff ffff88009bf27ed8 ffffffff81061106
> [  125.532114]  ffff880148020780 000000019be24928 0000000000000000 0000000000000000
> [  125.540571]  0000000000000000 0000000000000000 0000000000000000 0000000000000000
> [  125.549032] Call Trace:
> [  125.551814]  [<ffffffff81061106>] __restore_xstate_sig+0x246/0x6c0
> [  125.558841]  [<ffffffff810ace1f>] ? recalc_sigpending+0x1f/0x60
> [  125.565555]  [<ffffffff8109d054>] ia32_restore_sigcontext+0x194/0x1b0
> [  125.572874]  [<ffffffff8109d4bd>] sys32_rt_sigreturn+0xad/0xd0
> [  125.579505]  [<ffffffff817a0985>] ia32_ptregs_common+0x25/0x4b
> [  125.586129] Code: fb 7e e9 11 00 00 00 db e2 0f 77 db 83 44 06 00 00 0f 1f 80 00 00 00 00 0f 1f 44 00 00 b8 ff ff ff ff 48 8b bb 48 06 00 00 89 c2 <48> 0f c7 1f 31 c0 eb 20 0f 1f 44 00 00 bf 9a 00 00 00 e8 ce 11 
> [  125.608467] RIP  [<ffffffff810556cb>] math_state_restore+0x8b/0x1c0
> [  125.615599]  RSP <ffff88009bf27e08>
> [  125.619563] ---[ end trace 71f0a6784c4b2590 ]---


  parent reply	other threads:[~2015-03-05 18:41 UTC|newest]

Thread overview: 126+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-03-04 18:30 Dave Hansen
2015-03-04 19:06 ` Oleg Nesterov
2015-03-04 19:12   ` Dave Hansen
2015-03-04 20:06   ` Borislav Petkov
2015-03-05 15:14     ` Oleg Nesterov
     [not found]       ` <20150305182203.GA4203@redhat.com>
2015-03-05 18:34         ` Dave Hansen
2015-03-05 18:46           ` Oleg Nesterov
2015-03-05 18:41         ` Dave Hansen [this message]
2015-03-26 22:37         ` Yu, Fenghua
2015-03-26 22:43           ` Dave Hansen
2015-03-26 22:48             ` Yu, Fenghua
2015-03-27  7:30               ` Quentin Casasnovas
2015-03-27 19:06           ` Oleg Nesterov
2015-03-05  8:38   ` Quentin Casasnovas
2015-03-05 15:13     ` Oleg Nesterov
2015-03-05 18:42       ` Borislav Petkov
2015-03-05 22:16         ` Dave Hansen
2015-03-05 19:51 ` [PATCH 0/1] x86/fpu: math_state_restore() should not blindly disable irqs Oleg Nesterov
2015-03-05 19:51   ` [PATCH 1/1] " Oleg Nesterov
2015-03-05 20:11     ` Ingo Molnar
2015-03-05 21:25       ` Oleg Nesterov
2015-03-06  7:58         ` Ingo Molnar
2015-03-06 13:26           ` Oleg Nesterov
2015-03-06 13:39             ` Oleg Nesterov
2015-03-06 13:46             ` Ingo Molnar
2015-03-06 14:01               ` Oleg Nesterov
2015-03-06 14:17                 ` Oleg Nesterov
2015-03-06 15:00                 ` David Vrabel
2015-03-06 15:36                   ` Oleg Nesterov
2015-03-06 16:15                     ` David Vrabel
2015-03-06 16:31                       ` Oleg Nesterov
2015-03-06 17:33           ` Linus Torvalds
2015-03-06 18:15             ` Oleg Nesterov
2015-03-06 19:23             ` Andy Lutomirski
2015-03-06 22:00               ` Linus Torvalds
2015-03-06 22:28                 ` Andy Lutomirski
2015-03-07 10:36                   ` Ingo Molnar
2015-03-07 20:11                     ` Linus Torvalds
2015-03-08  8:55                       ` Ingo Molnar
2015-03-08 11:38                         ` Ingo Molnar
2015-03-08 13:59                         ` Andy Lutomirski
2015-03-08 14:38                           ` Andy Lutomirski
2015-03-07 10:32             ` Ingo Molnar
2015-03-07 15:38   ` [PATCH 0/1] x86/fpu: x86/fpu: avoid math_state_restore() without used_math() in __restore_xstate_sig() Oleg Nesterov
2015-03-07 15:38     ` [PATCH 1/1] " Oleg Nesterov
2015-03-09 14:07       ` Borislav Petkov
2015-03-09 14:34         ` Oleg Nesterov
2015-03-09 15:18           ` Borislav Petkov
2015-03-09 16:24             ` Oleg Nesterov
2015-03-09 16:53               ` Borislav Petkov
2015-03-09 17:05                 ` Oleg Nesterov
2015-03-09 17:23                   ` Borislav Petkov
2015-03-16 12:07       ` [tip:x86/urgent] x86/fpu: Avoid " tip-bot for Oleg Nesterov
2015-03-05 20:35 ` [PATCH 0/1] x86/fpu: math_state_restore() should not blindly disable irqs Oleg Nesterov
2015-03-09 17:10 ` [PATCH] x86/fpu: drop_fpu() should not assume that tsk == current Oleg Nesterov
2015-03-09 17:36   ` Rik van Riel
2015-03-09 17:48   ` Borislav Petkov
2015-03-09 18:06     ` Oleg Nesterov
2015-03-09 18:10       ` Borislav Petkov
2015-03-16 12:07   ` [tip:x86/urgent] x86/fpu: Drop_fpu() should not assume that tsk equals current tip-bot for Oleg Nesterov
2015-03-11 17:33 ` [PATCH 0/4] x86/fpu: avoid math_state_restore() on kthread exec Oleg Nesterov
2015-03-11 17:34   ` [PATCH 1/4] x86/fpu: document user_fpu_begin() Oleg Nesterov
2015-03-13  9:47     ` Borislav Petkov
2015-03-13 14:34       ` Oleg Nesterov
2015-03-23 12:20     ` [tip:x86/fpu] x86/fpu: Document user_fpu_begin() tip-bot for Oleg Nesterov
2015-03-11 17:34   ` [PATCH 2/4] x86/fpu: introduce restore_init_xstate() Oleg Nesterov
2015-03-13 10:34     ` Borislav Petkov
2015-03-13 14:39       ` Oleg Nesterov
2015-03-13 15:20         ` Borislav Petkov
2015-03-16 19:05           ` Rik van Riel
2015-03-23 12:20     ` [tip:x86/fpu] x86/fpu: Introduce restore_init_xstate() tip-bot for Oleg Nesterov
2015-03-11 17:34   ` [PATCH 3/4] x86/fpu: use restore_init_xstate() instead of math_state_restore() on kthread exec Oleg Nesterov
2015-03-13 10:48     ` Borislav Petkov
2015-03-13 14:45       ` Oleg Nesterov
2015-03-13 15:51         ` Borislav Petkov
2015-03-23 12:21     ` [tip:x86/fpu] x86/fpu: Use " tip-bot for Oleg Nesterov
2015-03-11 17:35   ` [PATCH 4/4] x86/fpu: don't abuse drop_init_fpu() in flush_thread() Oleg Nesterov
2015-03-13 10:52     ` Borislav Petkov
2015-03-13 14:55       ` Oleg Nesterov
2015-03-13 16:19         ` Borislav Petkov
2015-03-13 16:26           ` Oleg Nesterov
2015-03-13 19:27             ` Borislav Petkov
2015-03-14 14:48               ` Oleg Nesterov
2015-03-15 17:36                 ` Borislav Petkov
2015-03-15 18:16                   ` Oleg Nesterov
2015-03-15 18:50                     ` Borislav Petkov
2015-03-15 20:04                       ` Oleg Nesterov
2015-03-15 20:38                         ` Borislav Petkov
2015-03-16  9:35                           ` Borislav Petkov
2015-03-16 10:28                             ` Ingo Molnar
2015-03-16 14:39                             ` Oleg Nesterov
2015-03-16 15:26                               ` Borislav Petkov
2015-03-16 15:34                             ` Andy Lutomirski
2015-03-16 15:35                               ` Borislav Petkov
2015-03-13 17:30     ` [PATCH v2 " Oleg Nesterov
2015-03-14 10:55       ` Borislav Petkov
2015-03-14 10:57         ` [PATCH] x86/fpu: Fold __drop_fpu() into its sole user Borislav Petkov
2015-03-14 15:15           ` Oleg Nesterov
2015-03-16 10:27           ` Ingo Molnar
2015-03-23 12:21       ` [tip:x86/fpu] x86/fpu: Don't abuse drop_init_fpu() in flush_thread() tip-bot for Oleg Nesterov
2015-03-13 18:26 ` [PATCH 0/1] x86/cpu: don't allocate fpu->state for swapper/0 Oleg Nesterov
2015-03-13 18:27   ` [PATCH 1/1] " Oleg Nesterov
2015-03-16 10:18     ` Borislav Petkov
2015-03-23 12:22     ` [tip:x86/fpu] x86/fpu: Don't " tip-bot for Oleg Nesterov
2015-03-14 11:16   ` [PATCH 0/1] x86/cpu: don't " Borislav Petkov
2015-03-14 15:13     ` [PATCH 0/1] x86/cpu: kill eager_fpu_init_bp() Oleg Nesterov
2015-03-14 15:13       ` [PATCH 1/1] " Oleg Nesterov
2015-03-16 12:44         ` Borislav Petkov
2015-03-23 12:22         ` [tip:x86/fpu] x86/fpu: Kill eager_fpu_init_bp() tip-bot for Oleg Nesterov
2015-03-15 16:49 ` [PATCH RFC 0/2] x86/fpu: avoid "xstate_fault" in xsave_user/xrestore_user Oleg Nesterov
2015-03-15 16:50   ` [PATCH RFC 1/2] x86: introduce __user_insn() and __check_insn() Oleg Nesterov
2015-03-15 16:50   ` [PATCH RFC 2/2] x86/fpu: change xsave_user() and xrestore_user() to use __user_insn() Oleg Nesterov
2015-03-16 22:43     ` Quentin Casasnovas
2015-03-17  9:35       ` Borislav Petkov
2015-03-16 14:36   ` [PATCH RFC 0/2] x86/fpu: avoid "xstate_fault" in xsave_user/xrestore_user Borislav Petkov
2015-03-16 14:57     ` Oleg Nesterov
2015-03-16 17:58       ` Borislav Petkov
2015-03-16 22:37   ` Quentin Casasnovas
2015-03-17  9:47     ` Borislav Petkov
2015-03-17 10:00       ` Quentin Casasnovas
2015-03-17 11:20         ` Borislav Petkov
2015-03-17 11:36           ` Quentin Casasnovas
2015-03-17 12:07             ` Borislav Petkov
2015-03-18  9:06               ` Quentin Casasnovas
2015-03-18  9:53                 ` Borislav Petkov
2015-03-17 10:07       ` Quentin Casasnovas

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