Re: [PATCH] mm, kasan: don't poison boot memory

[George Kennedy <george.kennedy@oracle.com>]

On 2/23/2021 10:47 AM, Mike Rapoport wrote:
> Hi George,
>
> On Tue, Feb 23, 2021 at 09:35:32AM -0500, George Kennedy wrote:
>> On 2/23/2021 5:33 AM, Mike Rapoport wrote:
>>> (re-added CC)
>>>
>>> On Mon, Feb 22, 2021 at 08:24:59PM -0500, George Kennedy wrote:
>>>> On 2/22/2021 4:55 PM, Mike Rapoport wrote:
>>>>> On Mon, Feb 22, 2021 at 01:42:56PM -0500, George Kennedy wrote:
>>>>>> On 2/22/2021 11:13 AM, David Hildenbrand wrote:
>>>>>>> On 22.02.21 16:13, George Kennedy wrote:
>>>>>>>
>>>>>>> The PFN 0xbe453 looks a little strange, though. Do we expect ACPI tables
>>>>>>> close to 3 GiB ? No idea. Could it be that you are trying to map a wrong
>>>>>>> table? Just a guess.
>>>>>>>
>>>>>>>> What would be  the correct way to reserve the page so that the above
>>>>>>>> would not be hit?
>>>>>>> I would have assumed that if this is a binary blob, that someone (which
>>>>>>> I think would be acpi code) reserved via memblock_reserve() early during
>>>>>>> boot.
>>>>>>>
>>>>>>> E.g., see drivers/acpi/tables.c:acpi_table_upgrade()->memblock_reserve().
>>>>>> acpi_table_upgrade() gets called, but bails out before memblock_reserve() is
>>>>>> called. Thus, it appears no pages are getting reserved.
>>>>> acpi_table_upgrade() does not actually reserve memory but rather open
>>>>> codes memblock allocation with memblock_find_in_range() +
>>>>> memblock_reserve(), so it does not seem related anyway.
>>>>>
>>>>> Do you have by chance a full boot log handy?
>>>> Hello Mike,
>>>>
>>>> Are you after the console output? See attached.
>>>>
>>>> It includes my patch to set PG_Reserved along with the dump_page() debug
>>>> that David asked for - see: "page:"
>>> So, iBFT is indeed at pfn 0xbe453:
>>>
>>> [    0.077698] ACPI: iBFT 0x00000000BE453000 000800 (v01 BOCHS  BXPCFACP 00000000      00000000)
>>> and it's in E820_TYPE_RAM region rather than in ACPI data:
>>>
>>> [    0.000000] BIOS-e820: [mem 0x0000000000810000-0x00000000008fffff] ACPI NVS
>>> [    0.000000] BIOS-e820: [mem 0x0000000000900000-0x00000000be49afff] usable
>>> [    0.000000] BIOS-e820: [mem 0x00000000be49b000-0x00000000be49bfff] ACPI data
>>>
>>> I could not find anywhere in x86 setup or in ACPI tables parsing the code
>>> that reserves this memory or any other ACPI data for that matter. It could
>>> be that I've missed some copying of the data to statically allocated
>>> initial_tables, but AFAICS any ACPI data that was not marked as such in
>>> e820 tables by BIOS resides in memory that is considered as free.
>>>
>> Close...
>>
>> Applied the patch, see "[   30.136157] iBFT detected.", but now hit the
>> following (missing iounmap()? see full console output attached):
>>
>> diff --git a/drivers/firmware/iscsi_ibft_find.c
>> b/drivers/firmware/iscsi_ibft_find.c
>> index 64bb945..2e5e040 100644
>> --- a/drivers/firmware/iscsi_ibft_find.c
>> +++ b/drivers/firmware/iscsi_ibft_find.c
>> @@ -80,6 +80,21 @@ static int __init find_ibft_in_mem(void)
>>   done:
>>          return len;
>>   }
>> +
>> +static void __init acpi_find_ibft_region(void)
>> +{
>> +       int i;
>> +       struct acpi_table_header *table = NULL;
>> +
>> +       if (acpi_disabled)
>> +               return;
>> +
>> +       for (i = 0; i < ARRAY_SIZE(ibft_signs) && !ibft_addr; i++) {
>> +               acpi_get_table(ibft_signs[i].sign, 0, &table);
>> +               ibft_addr = (struct acpi_table_ibft *)table;
> Can you try adding
>
> 	acpi_put_table(table);
>
> here?
Mike,

It now crashes here:

[    0.051019] ACPI: Early table checksum verification disabled
[    0.056721] ACPI: RSDP 0x00000000BFBFA014 000024 (v02 BOCHS )
[    0.057874] ACPI: XSDT 0x00000000BFBF90E8 00004C (v01 BOCHS BXPCFACP 
00000001      01000013)
[    0.059590] ACPI: FACP 0x00000000BFBF5000 000074 (v01 BOCHS BXPCFACP 
00000001 BXPC 00000001)
[    0.061306] ACPI: DSDT 0x00000000BFBF6000 00238D (v01 BOCHS BXPCDSDT 
00000001 BXPC 00000001)
[    0.063006] ACPI: FACS 0x00000000BFBFD000 000040
[    0.063938] ACPI: APIC 0x00000000BFBF4000 000090 (v01 BOCHS BXPCAPIC 
00000001 BXPC 00000001)
[    0.065638] ACPI: HPET 0x00000000BFBF3000 000038 (v01 BOCHS BXPCHPET 
00000001 BXPC 00000001)
[    0.067335] ACPI: BGRT 0x00000000BE49B000 000038 (v01 INTEL EDK2     
00000002      01000013)
[    0.069030] ACPI: iBFT 0x00000000BE453000 000800 (v01 BOCHS BXPCFACP 
00000000      00000000)
[    0.070734] XXX acpi_find_ibft_region:
[    0.071468] XXX iBFT, status=0
[    0.072073] XXX about to call acpi_put_table()... 
ibft_addr=ffffffffff240000
[    0.073449] XXX acpi_find_ibft_region(EXIT):
PANIC: early exception 0x0e IP 10:ffffffff9259f439 error 0 cr2 
0xffffffffff240004
[    0.075711] CPU: 0 PID: 0 Comm: swapper Not tainted 5.11.0-34a2105 #8
[    0.076983] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), 
BIOS 0.0.0 02/06/2015
[    0.078579] RIP: 0010:find_ibft_region+0x470/0x577
[    0.079541] Code: f1 40 0f 9e c6 84 c9 0f 95 c1 40 84 ce 75 11 83 e0 
07 38 c2 0f 9e c1 84 d2 0f 95 c0 84 c1 74 0a be 04 00 00 00 e8 37 f8 5f 
ef <8b> 5b 04 4c 89 fa b8 ff ff 37 00 48 c1 ea 03 48 c1 e0 2a 81 c3 ff
[    0.083207] RSP: 0000:ffffffff8fe07ca8 EFLAGS: 00010046 ORIG_RAX: 
0000000000000000
[    0.084709] RAX: 0000000000000000 RBX: ffffffffff240000 RCX: 
ffffffff815fcf01
[    0.086109] RDX: dffffc0000000000 RSI: 0000000000000001 RDI: 
ffffffffff240004
[    0.087509] RBP: ffffffff8fe07d60 R08: fffffbfff1fc0f21 R09: 
fffffbfff1fc0f21
[    0.088911] R10: ffffffff8fe07907 R11: fffffbfff1fc0f20 R12: 
ffffffff8fe07d38
[    0.090310] R13: 0000000000000001 R14: 0000000000000001 R15: 
ffffffff8fe07e80
[    0.091716] FS:  0000000000000000(0000) GS:ffffffff92409000(0000) 
knlGS:0000000000000000
[    0.093304] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[    0.094435] CR2: ffffffffff240004 CR3: 0000000027630000 CR4: 
00000000000006a0
[    0.095843] Call Trace:
[    0.096345]  ? acpi_table_init+0x3eb/0x428
[    0.097164]  ? dmi_id_init+0x871/0x871
[    0.097912]  ? early_memunmap+0x22/0x27
[    0.098683]  ? smp_scan_config+0x20e/0x230
[    0.099500]  setup_arch+0xd3e/0x181d
[    0.100221]  ? reserve_standard_io_resources+0x3e/0x3e
[    0.101265]  ? __sanitizer_cov_trace_pc+0x21/0x50
[    0.102203]  ? vprintk_func+0xe9/0x200
[    0.102953]  ? printk+0xac/0xd4
[    0.103589]  ? record_print_text.cold.38+0x16/0x16
[    0.104540]  ? write_comp_data+0x2f/0x90
[    0.105325]  ? __sanitizer_cov_trace_pc+0x21/0x50
[    0.106262]  start_kernel+0x6c/0x474
[    0.106981]  x86_64_start_reservations+0x37/0x39
[    0.107902]  x86_64_start_kernel+0x7b/0x7e
[    0.108722]  secondary_startup_64_no_verify+0xb0/0xbb


Added debug to dump out the ibft_addr:

[root@gkennedy-20210107-1202 linux-upwork]# git diff
diff --git a/drivers/firmware/iscsi_ibft_find.c 
b/drivers/firmware/iscsi_ibft_find.c
index 2e5e040..a246373 100644
--- a/drivers/firmware/iscsi_ibft_find.c
+++ b/drivers/firmware/iscsi_ibft_find.c
@@ -83,16 +83,22 @@ static int __init find_ibft_in_mem(void)

  static void __init acpi_find_ibft_region(void)
  {
-       int i;
+       int i, status;
         struct acpi_table_header *table = NULL;
-
+printk(KERN_ERR "XXX acpi_find_ibft_region:\n");
         if (acpi_disabled)
                 return;

         for (i = 0; i < ARRAY_SIZE(ibft_signs) && !ibft_addr; i++) {
-               acpi_get_table(ibft_signs[i].sign, 0, &table);
-               ibft_addr = (struct acpi_table_ibft *)table;
+               status = acpi_get_table(ibft_signs[i].sign, 0, &table);
+               printk(KERN_ERR "XXX %s, status=%x\n", 
ibft_signs[i].sign, status);
+               if (ACPI_SUCCESS(status)) {
+                       ibft_addr = (struct acpi_table_ibft *)table;
+                       printk(KERN_ERR "XXX about to call 
acpi_put_table()... ibft_addr=%llx\n", (u64)ibft_addr);
+                       acpi_put_table(table);
+               }
         }
+printk(KERN_ERR "XXX acpi_find_ibft_region(EXIT):\n");
  }

  /*
(END)

George
>
>> +       }
>> +}
>> +