lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:	Thu, 20 Dec 2012 08:56:11 -0800
From:	Yinghai Lu <>
To:	"H. Peter Anvin" <>
Cc:	Jason Wessel <>,
	Jan Kiszka <>,
	Thomas Gleixner <>,
	Ingo Molnar <>,
	"Eric W. Biederman" <>,
	Andrew Morton <>,
Subject: Re: [PATCH v7 06/27] x86, 64bit: early #PF handler set page table

On Tue, Dec 18, 2012 at 1:07 PM, H. Peter Anvin <> wrote:
> On 12/18/2012 12:55 PM, Yinghai Lu wrote:
>> On Tue, Dec 18, 2012 at 12:49 PM, H. Peter Anvin <> wrote:
>>> On 12/18/2012 12:43 PM, Yinghai Lu wrote:
>>> That is putting the cart before the horse.  What is the specific requirement
>>> with kgdb here (I didn't see any email on that, please don't have private
>>> back conversations)?  Either way, however, kgdb is a tool to debug the
>>> kernel... having it a barrier for proper functionality of the kernel is not
>>> acceptable.
>> did not hear back from Jason or Jan.
>> Looks like last mail in LKML from Jason is about Oct 20
>> looks like kgdb is want DB, BP, and PF are set at first.
>> and just after that early_param for kgdbwait will get into to hold the kernel.
>> then command from kgdb could dump ram etc.
> So in that case, kgdb is broken and will need to be fixed up.  That
> happens all the time with debugging tools.

If there is a way that we can make all parties happy, we really should
not break KGDB.

Please reconsider to stop #PF handler in x86_64_start_kernel. in that case
1. microcode update still can use #PF handler to find microcode in
ramdisk and use it.
2. kernel that is loaded above 4G, could set mapping in C instead of
set that in head_64.S
   and use ioremap to access zero_page
3. KGDB still can call early_trap_init early before init_mem_mapping.

I put the change in for-x86-boot-v8 branch.
core patch is:;a=commitdiff;h=6fa4f1e68f0b67d0dc13d30c5ce6c3932697d08f


To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

Powered by blists - more mailing lists