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From: Eiichi Tsukata <devel@etsukata.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Borislav Petkov <bp@alien8.de>, Ingo Molnar <mingo@kernel.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Andrew Lutomirski <luto@kernel.org>, Peter Anvin <hpa@zytor.com>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Juergen Gross <jgross@suse.com>,
	Linux List Kernel Mailing <linux-kernel@vger.kernel.org>,
	He Zhe <zhe.he@windriver.com>,
	Joel Fernandes <joel@joelfernandes.org>
Subject: Re: [PATCH v2 5/7] x86/mm, tracing: Fix CR2 corruption
Date: Mon, 8 Jul 2019 17:58:49 +0900	[thread overview]
Message-ID: <48e29640-fedc-3e72-535c-27ef07b73938@etsukata.com> (raw)
In-Reply-To: <20190708074823.GV3402@hirez.programming.kicks-ass.net>



On 2019/07/08 16:48, Peter Zijlstra wrote:
...

> 
> Or are we going to put the CR2 save/restore on every single tracepoint?
> But then we also need it on the mcount/fentry stubs and we again have
> multiple places.
> 
> Whereas if we stick it in the entry path, like I proposed, we fix it in
> one location and we're done.
> 

Thanks to your detailed comments and the discussion, I've come to realize
that your solution "save CR2 early in the entry" is the simplest and reasonable.

By the way, is there possibility that the WARNING(#GP in execve(2)) which Steven
previously hit? : https://lore.kernel.org/lkml/20190321095502.47b51356@gandalf.local.home/

Even if there were, it will *Not* be the bug introduced by this patch series,
but the bug revealed by this series.

Thanks,

Eiichi

  reply	other threads:[~2019-07-08  8:58 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-04 19:55 [PATCH v2 0/7] Tracing vs CR2 (and cleanups) Peter Zijlstra
2019-07-04 19:55 ` [PATCH v2 1/7] x86/paravirt: Make read_cr2() CALLEE_SAVE Peter Zijlstra
2019-07-04 21:49   ` Andy Lutomirski
2019-07-10 19:53   ` Steven Rostedt
2019-07-04 19:55 ` [PATCH v2 2/7] x86/entry/32: Simplify common_exception Peter Zijlstra
2019-07-04 21:51   ` Andy Lutomirski
2019-07-10 20:11   ` Steven Rostedt
2019-07-10 20:14     ` Peter Zijlstra
2019-07-04 19:55 ` [PATCH v2 3/7] x86/entry/64: Simplify idtentry a little Peter Zijlstra
2019-07-04 21:54   ` Andy Lutomirski
2019-07-10 20:23   ` Steven Rostedt
2019-07-04 19:55 ` [PATCH v2 4/7] x86/entry/64: Update comments and sanity tests for create_gap Peter Zijlstra
2019-07-04 21:55   ` Andy Lutomirski
2019-07-10 20:24   ` Steven Rostedt
2019-07-04 19:56 ` [PATCH v2 5/7] x86/mm, tracing: Fix CR2 corruption Peter Zijlstra
2019-07-05  2:18   ` Linus Torvalds
2019-07-05  3:16     ` Andy Lutomirski
2019-07-05  3:27       ` Linus Torvalds
2019-07-05 13:49     ` Peter Zijlstra
2019-07-06 21:41       ` Linus Torvalds
2019-07-06 22:27         ` Steven Rostedt
2019-07-06 22:41           ` Linus Torvalds
2019-07-07  0:08             ` Linus Torvalds
2019-07-07  0:36               ` Andy Lutomirski
2019-07-06 23:50           ` Andy Lutomirski
2019-07-07  3:44           ` Eiichi Tsukata
2019-07-06 11:07     ` Eiichi Tsukata
2019-07-08  7:48       ` Peter Zijlstra
2019-07-08  8:58         ` Eiichi Tsukata [this message]
2019-07-08  9:42           ` Eiichi Tsukata
2019-07-09  5:17             ` Eiichi Tsukata
2019-07-07 15:10   ` Andy Lutomirski
2019-07-07 15:11     ` Andy Lutomirski
2019-07-07 18:17       ` Linus Torvalds
2019-07-10 20:27         ` Steven Rostedt
2019-07-11  6:45           ` Greg Kroah-Hartman
2019-07-11 12:12           ` Sasha Levin
2019-07-11 12:21           ` Peter Zijlstra
2019-07-04 19:56 ` [PATCH v2 6/7] x86/entry/64: Remove TRACE_IRQS_*_DEBUG Peter Zijlstra
2019-07-11  3:24   ` Steven Rostedt
2019-07-11  8:05     ` Peter Zijlstra
2019-07-04 19:56 ` [RFC][PATCH v2 7/7] x86/entry/64: Pull bits into C Peter Zijlstra

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