Re: [LKP] [x86/mm/ASLR] f47233c2d34: WARNING: CPU: 0 PID: 1 at arch/x86/mm/ioremap.c:63 __ioremap_check_ram+0x445/0x4a0()
From: Borislav Petkov
Date: Thu Feb 26 2015 - 05:31:50 EST
Hi,
On Thu, Feb 26, 2015 at 01:37:01PM +0800, Huang Ying wrote:
> FYI, we noticed the below changes on
>
> git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> commit f47233c2d34f243ecdaac179c3408a39ff9216a7 ("x86/mm/ASLR: Propagate base load address calculation")
>
>
> +---------------------------------------------------------+-------+------------+
> | | v3.19 | f47233c2d3 |
> +---------------------------------------------------------+-------+------------+
> | boot_successes | 54 | 0 |
> | boot_failures | 10 | 10 |
> | BUG:kernel_test_hang | 10 | |
> | WARNING:at_arch/x86/mm/ioremap.c:#__ioremap_check_ram() | 0 | 10 |
> | backtrace:create_setup_data_nodes | 0 | 10 |
> | backtrace:boot_params_ksysfs_init | 0 | 10 |
> | backtrace:kernel_init_freeable | 0 | 10 |
> +---------------------------------------------------------+-------+------------+
>
>
> [ 0.490087] NET: Registered protocol family 16
> [ 0.498533] cpuidle: using governor menu
> [ 0.499891] ------------[ cut here ]------------
> [ 0.500021] WARNING: CPU: 0 PID: 1 at arch/x86/mm/ioremap.c:63 __ioremap_check_ram+0x445/0x4a0()
> [ 0.501015] ioremap on RAM pfn 0x3416
> [ 0.502013] Modules linked in:
> [ 0.503017] CPU: 0 PID: 1 Comm: swapper Not tainted 3.19.0-04793-g2c303f7 #3
> [ 0.504013] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
> [ 0.505014] 0000000000000009 ffff880012d8bb88 ffffffff81cedc16 ffff880012d8bbc8
> [ 0.507424] ffffffff810dd1a0 0000000000000000 0000000000000001 0000000000000001
> [ 0.509420] 0000000000003416 0000000000000001 0000000000000001 ffff880012d8bc28
> [ 0.511415] Call Trace:
> [ 0.512028] [<ffffffff81cedc16>] dump_stack+0x2e/0x3e
> [ 0.513023] [<ffffffff810dd1a0>] warn_slowpath_common+0xe0/0x160
> [ 0.514021] [<ffffffff810dd316>] warn_slowpath_fmt+0x56/0x60
> [ 0.515022] [<ffffffff8107f4a5>] __ioremap_check_ram+0x445/0x4a0
> [ 0.516022] [<ffffffff8107f060>] ? trace_do_page_fault+0x9b0/0x9b0
> [ 0.517020] [<ffffffff810ec948>] walk_system_ram_range+0x128/0x140
> [ 0.518022] [<ffffffff82d9081f>] ? create_setup_data_nodes+0xd1/0x488
> [ 0.519019] [<ffffffff82d9081f>] ? create_setup_data_nodes+0xd1/0x488
> [ 0.520021] [<ffffffff8107f882>] __ioremap_caller+0x172/0x850
> [ 0.521021] [<ffffffff81080064>] ioremap_cache+0x24/0x30
> [ 0.522019] [<ffffffff82d9081f>] create_setup_data_nodes+0xd1/0x488
> [ 0.523023] [<ffffffff81493c9c>] ? internal_create_group+0x4ac/0x830
> [ 0.524020] [<ffffffff82d90c76>] boot_params_ksysfs_init+0xa0/0xf9
> [ 0.525020] [<ffffffff810005f1>] do_one_initcall+0x371/0x4c0
> [ 0.526019] [<ffffffff82d90bd6>] ? create_setup_data_nodes+0x488/0x488
> [ 0.527024] [<ffffffff82d8afd5>] kernel_init_freeable+0x368/0x4ba
> [ 0.528022] [<ffffffff81ce15d0>] ? rest_init+0x260/0x260
> [ 0.529020] [<ffffffff81ce15e6>] kernel_init+0x16/0x240
> [ 0.530023] [<ffffffff81d0253a>] ret_from_fork+0x7a/0xb0
> [ 0.531021] [<ffffffff81ce15d0>] ? rest_init+0x260/0x260
> [ 0.532033] ---[ end trace b6a2b7ddc92922e5 ]---
> [ 0.534367] ACPI: bus type PCI registered
thanks for the report.
So, AFAICT, this is caused by ksysfs ioremapping struct setup_data
for a short time so that it can count it and show it in
/sys/kernel/boot_params/setup_data/*
And, of course, the setup_data thing which we're using for kaslr param
passing is RAM and ioremap complains.
And currently I don't have a good idea how to fix it. Perhaps introduce
an ioremap_* something which suppresses the warning as we're going to
iounmap() right afterwards but that's ugly.
Hmmmm.
--
Regards/Gruss,
Boris.
ECO tip #101: Trim your mails when you reply.
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