PMD update corruption (sync question)

[Jon Masters]

On 03/02/2015 05:50 AM, Catalin Marinas wrote:
> On Mon, Mar 02, 2015 at 12:58:36AM -0500, Jon Masters wrote:

>> Test kernels running with an explicit DSB in all PTE update cases now
>> running overnight. Just in case.

...and stay up after 19 hours. But that's just timing I'm sure.

> It could be hiding some other problems.

I checked my GDB macros and they were correct BUT my debugger went out
to lunch soon after that dump so I suspect it was just garbage :)

Instead, for my immediate issue, I have a much more likely suspect. For
anyone interested in the followup, you should know that hardware page
table walkers generally do respond well when you feed them Makefiles:

0x43e81c0000: 20230a23 656b614d 656c6966 726f6620  : #.# Makefile for
0x43e81c0010: 65687420 462d4920 6563726f 69726420  :  the I-Force dri
0x43e81c0020: 0a726576 20230a23 4a207942 6e61686f  : ver.#.# By Johan
0x43e81c0030: 6544206e 7875656e 6f6a3c20 6e6e6168  : n Deneux <johann
0x43e81c0040: 6e65642e 40787565 69616d67 6f632e6c  : .deneux at gmail.co
0x43e81c0050: 230a3e6d 626f0a0a 28242d6a 464e4f43  : m>.#..obj-$(CONF
0x43e81c0060: 4a5f4749 5453594f 5f4b4349 524f4649  : IG_JOYSTICK_IFOR
0x43e81c0070: 09294543 69203d2b 63726f66 0a6f2e65  : CE).+= iforce.o.
0x43e81c0080: 6f66690a 2d656372 3d3a2079 6f666920  : .iforce-y := ifo
0x43e81c0090: 2d656372 6f2e6666 6f666920 2d656372  : rce-ff.o iforce-
0x43e81c00a0: 6e69616d 69206f2e 63726f66 61702d65  : main.o iforce-pa
0x43e81c00b0: 74656b63 0a6f2e73 726f6669 242d6563  : ckets.o.iforce-$
0x43e81c00c0: 4e4f4328 5f474946 53594f4a 4b434954  : (CONFIG_JOYSTICK
0x43e81c00d0: 4f46495f 5f454352 29323332 203d2b09  : _IFORCE_232).+=
0x43e81c00e0: 726f6669 732d6563 6f697265 690a6f2e  : iforce-serio.o.i
0x43e81c00f0: 63726f66 28242d65 464e4f43 4a5f4749  : force-$(CONFIG_J
0x43e81c0100: 5453594f 5f4b4349 524f4649 555f4543  : OYSTICK_IFORCE_U
0x43e81c0110: 09294253 69203d2b 63726f66 73752d65  : SB).+= iforce-us
0x43e81c0120: 0a6f2e62 00000000 00000000 00000000  : b.o.............

So that explains why things were falling over. It is likely indeed the
bad DMA I have been craving all along. And this time it was so gracious
as to give me the answer in plain ASCII :) I suspect there will be a
patch for a certain AHCI driver in the not too distant future.

Jon.