Re: [linux-next] CRASH on boot up (mm: don't offset memmap for flatmem)

From: Laura Abbott
Date: Fri Mar 20 2015 - 16:19:16 EST


On 3/20/2015 12:51 PM, Steven Rostedt wrote:
I downloaded the latest linux-next (next-20150320) and started to run
it against my ftrace tests, and it crashed immediately on boot up in my
i386 boot with the following:

Initmem setup node 0 [mem 0x0000000000001000-0x000000021edfffff]
On node 0 totalpages: 2061826
BUG: Int 6: CR2 (null)
EDI (null) ESI (null) EBP c1157e54 EBX 00000020
ESP c1157e50 ES 0000007b DS 0000007b
EDX 00000020 ECX c1157ff8 EAX f381e000
vec 00000006 err (null) EIP c0ca02f3 CS 00000060 flg 00210086
Stack: 001f7602 c1157ea8 c125d8d6 c101c0f1 (null) 001f7602 (null) 1edfffff
00000002 00000001 (null) c1157e98 c1157ea8 c125d2db 00000001 00000004
(null) 00000001 0021ee00 c1157ecc c1157ed4 c1157ee8 c1157efc c125df75
CPU: 0 PID: 0 Comm: swapper Not tainted 4.0.0-rc4-test-next-20150320+ #82
Hardware name: MSI MS-7823/CSM-H87M-G43 (MS-7823), BIOS V1.6 02/22/2014
00000000 00000000 c1157e00 c0ca62e3 00000020 c1157e54 c123d1d7 c12f19d5
00000006 00000000 00000000 00000000 c1157e54 00000020 c1157e50 0000007b
0000007b 00000020 c1157ff8 f381e000 00000006 00000000 c0ca02f3 00000060
Call Trace:
[<c0ca62e3>] dump_stack+0x41/0x52
[<c123d1d7>] early_idt_handler+0x6b/0x6b
[<c0ca02f3>] ? alloc_node_mem_map.constprop.91+0x76/0x7b
[<c125d8d6>] free_area_init_node+0x120/0x3bc
[<c125d2db>] ? find_min_pfn_for_node+0x5e/0x85
[<c125df75>] free_area_init_nodes+0x3d9/0x3ee
[<c124fb1b>] zone_sizes_init+0x3b/0x41
[<c125046c>] paging_init+0x97/0x9a
[<c1250545>] native_pagetable_init+0xd6/0xde
[<c0cb02fc>] ? _raw_write_unlock+0x22/0x25
[<c0441b37>] ? insert_resource_conflict+0x2f/0x35
[<c12418d5>] setup_arch+0xd04/0xe14
[<c123d7e6>] start_kernel+0x8a/0x3e6
[<c123d30f>] ? reserve_ebda_region+0x57/0x59
[<c123d2b4>] i386_start_kernel+0x82/0x86

I bisected it down to this commit:

commit e928abcb309c3423e27680c845b1c7c374a2bb50
Author: Laura Abbott <lauraa@xxxxxxxxxxxxxx>
Date: Fri Mar 20 11:13:27 2015 +1100
Subject: mm: don't offset memmap for flatmem


Reverting this commit allows my box to boot once again.

Let me know if you need my config or any other info.

-- Steve


Thanks for the report. 0/2 on this particular bug.
Andrew has dropped this for now.
Can you share your .config ? I have a couple of theories
but I may not get a chance to experiment with anything.
I'm suspecting either the assert is wrong or the math
is still incorrect.

Thanks,
Laura

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