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From: Dave Hansen <dave.hansen@linux.intel.com>
To: Andy Lutomirski <luto@amacapital.net>
Cc: linux-kernel@vger.kernel.org, sean.j.christopherson@intel.com,
	peterz@infradead.org, tglx@linutronix.de, x86@kernel.org,
	luto@kernel.org
Subject: Re: [RFC][PATCH 2/8] x86/mm: break out kernel address space handling
Date: Fri, 7 Sep 2018 15:37:46 -0700	[thread overview]
Message-ID: <90a3e9c8-61df-f1dc-0d5c-b71342835f59@linux.intel.com> (raw)
In-Reply-To: <CD6177E3-BDE5-443F-9A28-351EAE0BE5BA@amacapital.net>

On 09/07/2018 03:21 PM, Andy Lutomirski wrote:
>> +static void
>> +do_kern_addr_space_fault(struct pt_regs *regs, unsigned long hw_error_code,
>> +             unsigned long address)
>> +{
>
> Can you add a comment above this documenting *when* it’s called? Is
> it all faults, !user_mode faults, or !PF_USER?

Yep, can do.

>> +    /*
>> +     * This is a "bad" fault in the kernel address space.  There
>> +     * is no reasonable explanation for it.  We will either kill
>> +     * the process for making a bad access, or oops the kernel.
>> +     */
> 
> Or call an extable handler?
> 
> Maybe the wording should be less scary, e.g. “this fault is a genuine
> error. Send a signal, call an exception handler, or oops, as
> appropriate.”

Yeah, the real behavior is quite a bit more subtle than I'm letting on.
I'll tone it down.

  reply	other threads:[~2018-09-07 22:38 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-09-07 19:48 [RFC][PATCH 0/8] x86/mm: page fault handling cleanups Dave Hansen
2018-09-07 19:48 ` [RFC][PATCH 1/8] x86/mm: clarify hardware vs. software "error_code" Dave Hansen
2018-09-07 22:48   ` Andy Lutomirski
2018-09-10 20:07     ` Dave Hansen
2018-09-10 21:17       ` Andy Lutomirski
2018-09-07 19:48 ` [RFC][PATCH 2/8] x86/mm: break out kernel address space handling Dave Hansen
2018-09-07 21:06   ` Sean Christopherson
2018-09-07 21:51     ` Dave Hansen
2018-09-07 22:21   ` Andy Lutomirski
2018-09-07 22:37     ` Dave Hansen [this message]
2018-09-07 19:48 ` [RFC][PATCH 3/8] x86/mm: break out user " Dave Hansen
2018-09-08  9:38   ` Peter Zijlstra
2018-09-10 20:20     ` Dave Hansen
2018-09-07 19:48 ` [RFC][PATCH 4/8] x86/mm: add clarifying comments for user addr space Dave Hansen
2018-09-07 19:49 ` [RFC][PATCH 5/8] x86/mm: fix exception table comments Dave Hansen
2018-09-07 21:04   ` Sean Christopherson
2018-09-07 21:51     ` Dave Hansen
2018-09-10 20:43       ` Sean Christopherson
2018-09-08  0:37   ` Jann Horn
2018-09-07 19:49 ` [RFC][PATCH 6/8] x86/mm: add vsyscall address helper Dave Hansen
2018-09-08  0:46   ` Jann Horn
2018-09-07 19:49 ` [RFC][PATCH 7/8] x86/mm/vsyscall: consider vsyscall page part of user address space Dave Hansen
2018-09-07 22:58   ` Andy Lutomirski
2018-09-08  1:16   ` Jann Horn
2018-09-07 19:49 ` [RFC][PATCH 8/8] x86/mm: remove spurious fault pkey check Dave Hansen

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