From: Peter Zijlstra <peterz@infradead.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
"H. Peter Anvin" <hpa@zytor.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@kernel.org>, Borislav Petkov <bp@alien8.de>,
Andy Lutomirski <luto@amacapital.net>,
Joel Fernandes <joel@joelfernandes.org>,
He Zhe <zhe.he@windriver.com>,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [RFC][PATCH] tracing/x86: Save CR2 before tracing irqsoff on error_entry
Date: Thu, 21 Mar 2019 10:02:41 +0100 [thread overview]
Message-ID: <20190321090241.GL6521@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20190321083317.GL6058@hirez.programming.kicks-ass.net>
On Thu, Mar 21, 2019 at 09:33:17AM +0100, Peter Zijlstra wrote:
I'm thinking this problem wasn't new.
> idtentry page_fault do_page_fault has_error_code=1
> call error_entry
> TRACE_IRQS_OFF
> call trace_hardirqs_off*
> <tracer stuff>
> <fault> # modifies CR2
CALL_enter_from_user_mode
__context_tracking_exit()
trace_user_exit(0)
#PF
> call do_page_fault
> address = read_cr2(); /* whoopsie */
And that also isn't fixed by your patch.
I'm trying to make idtentry put cr2 in rdx, such that do_page_fault()
takes address as a 3rd argument, but I'm still fighting that context
tracking nonsense.
next prev parent reply other threads:[~2019-03-21 9:02 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-21 2:15 Steven Rostedt
2019-03-21 8:33 ` Peter Zijlstra
2019-03-21 9:02 ` Peter Zijlstra [this message]
2019-03-21 10:45 ` Peter Zijlstra
2019-03-21 13:32 ` Steven Rostedt
2019-03-21 13:55 ` Steven Rostedt
2019-03-21 17:23 ` Linus Torvalds
2019-03-21 17:22 ` Peter Zijlstra
2019-03-21 18:05 ` Andy Lutomirski
2019-03-21 18:10 ` Steven Rostedt
2019-03-21 18:27 ` Andy Lutomirski
2019-03-21 20:50 ` Peter Zijlstra
2019-03-22 2:52 ` Andy Lutomirski
2019-03-21 18:28 ` Peter Zijlstra
2019-03-21 18:55 ` Steven Rostedt
2019-03-21 19:31 ` Peter Zijlstra
2019-03-21 19:50 ` Steven Rostedt
2019-03-21 20:03 ` Peter Zijlstra
2019-03-21 20:11 ` Steven Rostedt
2019-03-21 18:18 ` Linus Torvalds
2019-03-21 18:20 ` Andy Lutomirski
2019-03-21 18:25 ` Linus Torvalds
2019-03-21 18:37 ` Peter Zijlstra
2019-03-21 18:39 ` Andy Lutomirski
2019-03-21 20:00 ` Andrew Cooper
2019-03-21 20:35 ` Steven Rostedt
2019-03-21 18:38 ` Andy Lutomirski
2019-03-21 18:42 ` Peter Zijlstra
2019-03-21 18:22 ` hpa
2019-03-22 5:54 ` Juergen Gross
2019-03-21 18:27 ` Peter Zijlstra
2019-03-21 18:28 ` Andy Lutomirski
2019-03-21 18:33 ` Peter Zijlstra
2019-03-21 13:04 ` Steven Rostedt
2019-04-17 1:52 ` He Zhe
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