linux-kernel - Re: [PATCH] x86/microcode: Adjust ramdisk address when accessing by virtual address

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Date:   Mon, 19 Dec 2016 11:10:29 -0500
From:   Boris Ostrovsky <boris.ostrovsky@...cle.com>
To:     Borislav Petkov <bp@...en8.de>
Cc:     x86@...nel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] x86/microcode: Adjust ramdisk address when accessing by
 virtual address

On 12/19/2016 10:37 AM, Borislav Petkov wrote:
> On Mon, Dec 19, 2016 at 10:32:13AM -0500, Boris Ostrovsky wrote:
>> When searching for microcode in the ramdisk image we need to adjust the
>> start address after paging has been turned on (in 32-bit mode).
> I need more info:
>
> * Is this fixing a real issue?
>
> * how do you reproduce this?
>
> * kernel version
>
> * .config
>
> * initrd you're using
>
> Thanks.

Before you ask --- this is baremetal, from this morning's mainline. Your
series from yesterday is not applied but I don't think it had a fix for
this problem.

config attached. I'll see how I can get you the initrd.

Here is the splat.

[    1.865226] BUG: unable to handle kernel paging request at 1aae3000
[    1.871484] IP: find_cpio_data+0x69/0x220
[    1.875482] *pdpt = 0000000000000000 *pde = 0000000000000000
[    1.875483]
[    1.882701] Oops: 0000 [#1] SMP
[    1.885834] Modules linked in:
[    1.888883] CPU: 0 PID: 1 Comm: swapper/0 Not tainted
4.9.0upstream-11751-ge313a9b-dirty #3
[    1.897215] Hardware name: MSI MS-7680/H61M-P23 (MS-7680), BIOS V17.0
03/14/2011
[    1.904595] task: f2faf4c0 task.stack: f2fb0000
[    1.909115] EIP: find_cpio_data+0x69/0x220
[    1.913201] EFLAGS: 00210212 CPU: 0
[    1.916682] EAX: 00000025 EBX: 1aae3000 ECX: 00000026 EDX: f2fb1e64
[    1.922935] ESI: 054fbe4d EDI: 00000000 EBP: f2fb1e90 ESP: f2fb1e00
[    1.929188]  DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068
[    1.934574] CR0: 80050033 CR2: 1aae3000 CR3: 01b06000 CR4: 000406f0
[    1.940827] Call Trace:
[    1.943268]  ? kmemleak_alloc+0x3a/0x50
[    1.947096]  ? __d_instantiate+0x30/0xe0
[    1.951011]  find_microcode_in_initrd+0x5e/0x70
[    1.955529]  save_microcode_in_initrd_intel+0x28/0x5c
[    1.960569]  ? debugfs_create_mode_unsafe+0x2e/0x80
[    1.965435]  ? debugfs_create_u64+0x2d/0x40
[    1.969607]  save_microcode_in_initrd+0x20/0x3c
[    1.974127]  do_one_initcall+0x3c/0x160
[    1.977955]  ? centaur_init_mtrr+0x11/0x11
[    1.982041]  ? kernel_init_freeable+0x132/0x1ff
[    1.986562]  ? parse_args+0x245/0x3a0
[    1.990215]  kernel_init_freeable+0x150/0x1ff
[    1.994562]  ? kernel_init_freeable+0x1ff/0x1ff
[    1.999080]  ? rest_init+0x70/0x70
[    2.002474]  kernel_init+0xb/0x100
[    2.005867]  ? schedule_tail_wrapper+0x9/0xc
[    2.010126]  ret_from_fork+0x19/0x24
[    2.013693] Code: c7 45 e8 00 00 00 00 c7 45 ec 00 00 00 00 66 c7 45
f0 00 00 e8 f9 e5 00 00 83 7d 08 6e 89 45 8c 76 28 8b 5d 94 8d 55 d4 89
55 84 <80> 3b 00 b8 06 00 00 00 8d 7d a0 75 62 83 6d 08 04 83 c3 04 83
[    2.032443] EIP: find_cpio_data+0x69/0x220 SS:ESP: 0068:f2fb1e00
[    2.038432] CR2: 000000001aae3000
[    2.041738] ---[ end trace 36446d1f414ac27d ]---
[    2.046343] Kernel panic - not syncing: Fatal exception
[    2.051559] ---[ end Kernel panic - not syncing: Fatal exception


View attachment "config.i386" of type "text/plain" (105036 bytes)