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

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

On 2/25/2021 3:53 AM, Mike Rapoport wrote:
> Hi George,
>
>> On 2/24/2021 5:37 AM, Mike Rapoport wrote:
>>> On Tue, Feb 23, 2021 at 04:46:28PM -0500, George Kennedy wrote:
>>>> Mike,
>>>>
>>>> Still no luck.
>>>>
>>>> [   30.193723] iscsi: registered transport (iser)
>>>> [   30.195970] iBFT detected.
>>>> [   30.196571] BUG: unable to handle page fault for address: ffffffffff240004
>>> Hmm, we cannot set ibft_addr to early pointer to the ACPI table.
>>> Let's try something more disruptive and move the reservation back to
>>> iscsi_ibft_find.c.
>>>
>>> diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
>>> index 7bdc0239a943..c118dd54a747 100644
>>> --- a/arch/x86/kernel/acpi/boot.c
>>> +++ b/arch/x86/kernel/acpi/boot.c
>>> @@ -1551,6 +1551,7 @@ void __init acpi_boot_table_init(void)
>>>    	if (acpi_disabled)
>>>    		return;
>>> +#if 0
>>>    	/*
>>>    	 * Initialize the ACPI boot-time table parser.
>>>    	 */
>>> @@ -1558,6 +1559,7 @@ void __init acpi_boot_table_init(void)
>>>    		disable_acpi();
>>>    		return;
>>>    	}
>>> +#endif
>>>    	acpi_table_parse(ACPI_SIG_BOOT, acpi_parse_sbf);
>>> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
>>> index d883176ef2ce..c615ce96c9a2 100644
>>> --- a/arch/x86/kernel/setup.c
>>> +++ b/arch/x86/kernel/setup.c
>>> @@ -570,16 +570,6 @@ void __init reserve_standard_io_resources(void)
>>>    }
>>> -static __init void reserve_ibft_region(void)
>>> -{
>>> -	unsigned long addr, size = 0;
>>> -
>>> -	addr = find_ibft_region(&size);
>>> -
>>> -	if (size)
>>> -		memblock_reserve(addr, size);
>>> -}
>>> -
>>>    static bool __init snb_gfx_workaround_needed(void)
>>>    {
>>>    #ifdef CONFIG_PCI
>>> @@ -1032,6 +1022,12 @@ void __init setup_arch(char **cmdline_p)
>>>    	 */
>>>    	find_smp_config();
>>> +	/*
>>> +	 * Initialize the ACPI boot-time table parser.
>>> +	 */
>>> +	if (acpi_table_init())
>>> +		disable_acpi();
>>> +
>>>    	reserve_ibft_region();
>>>    	early_alloc_pgt_buf();
>>> diff --git a/drivers/firmware/iscsi_ibft_find.c b/drivers/firmware/iscsi_ibft_find.c
>>> index 64bb94523281..01be513843d6 100644
>>> --- a/drivers/firmware/iscsi_ibft_find.c
>>> +++ b/drivers/firmware/iscsi_ibft_find.c
>>> @@ -47,7 +47,25 @@ static const struct {
>>>    #define VGA_MEM 0xA0000 /* VGA buffer */
>>>    #define VGA_SIZE 0x20000 /* 128kB */
>>> -static int __init find_ibft_in_mem(void)
>>> +static void __init *acpi_find_ibft_region(void)
>>> +{
>>> +	int i;
>>> +	struct acpi_table_header *table = NULL;
>>> +	acpi_status status;
>>> +
>>> +	if (acpi_disabled)
>>> +		return NULL;
>>> +
>>> +	for (i = 0; i < ARRAY_SIZE(ibft_signs) && !ibft_addr; i++) {
>>> +		status = acpi_get_table(ibft_signs[i].sign, 0, &table);
>>> +		if (ACPI_SUCCESS(status))
>>> +			return table;
>>> +	}
>>> +
>>> +	return NULL;
>>> +}
>>> +
>>> +static void __init *find_ibft_in_mem(void)
>>>    {
>>>    	unsigned long pos;
>>>    	unsigned int len = 0;
>>> @@ -70,35 +88,44 @@ static int __init find_ibft_in_mem(void)
>>>    				/* if the length of the table extends past 1M,
>>>    				 * the table cannot be valid. */
>>>    				if (pos + len <= (IBFT_END-1)) {
>>> -					ibft_addr = (struct acpi_table_ibft *)virt;
>>>    					pr_info("iBFT found at 0x%lx.\n", pos);
>>> -					goto done;
>>> +					return virt;
>>>    				}
>>>    			}
>>>    		}
>>>    	}
>>> -done:
>>> -	return len;
>>> +
>>> +	return NULL;
>>>    }
>>> +
>>> +static void __init *find_ibft(void)
>>> +{
>>> +	/* iBFT 1.03 section 1.4.3.1 mandates that UEFI machines will
>>> +	 * only use ACPI for this */
>>> +	if (!efi_enabled(EFI_BOOT))
>>> +		return find_ibft_in_mem();
>>> +	else
>>> +		return acpi_find_ibft_region();
>>> +}
>>> +
>>>    /*
>>>     * Routine used to find the iSCSI Boot Format Table. The logical
>>>     * kernel address is set in the ibft_addr global variable.
>>>     */
>>> -unsigned long __init find_ibft_region(unsigned long *sizep)
>>> +void __init reserve_ibft_region(void)
>>>    {
>>> -	ibft_addr = NULL;
>>> +	struct acpi_table_ibft *table;
>>> +	unsigned long size;
>>> -	/* iBFT 1.03 section 1.4.3.1 mandates that UEFI machines will
>>> -	 * only use ACPI for this */
>>> +	table = find_ibft();
>>> +	if (!table)
>>> +		return;
>>> -	if (!efi_enabled(EFI_BOOT))
>>> -		find_ibft_in_mem();
>>> -
>>> -	if (ibft_addr) {
>>> -		*sizep = PAGE_ALIGN(ibft_addr->header.length);
>>> -		return (u64)virt_to_phys(ibft_addr);
>>> -	}
>>> +	size = PAGE_ALIGN(table->header.length);
>>> +	memblock_reserve(virt_to_phys(table), size);
>>> -	*sizep = 0;
>>> -	return 0;
>>> +	if (efi_enabled(EFI_BOOT))
>>> +		acpi_put_table(&table->header);
>>> +	else
>>> +		ibft_addr = table;
>>>    }
>>> diff --git a/include/linux/iscsi_ibft.h b/include/linux/iscsi_ibft.h
>>> index b7b45ca82bea..da813c891990 100644
>>> --- a/include/linux/iscsi_ibft.h
>>> +++ b/include/linux/iscsi_ibft.h
>>> @@ -26,13 +26,9 @@ extern struct acpi_table_ibft *ibft_addr;
>>>     * mapped address is set in the ibft_addr variable.
>>>     */
>>>    #ifdef CONFIG_ISCSI_IBFT_FIND
>>> -unsigned long find_ibft_region(unsigned long *sizep);
>>> +void reserve_ibft_region(void);
>>>    #else
>>> -static inline unsigned long find_ibft_region(unsigned long *sizep)
>>> -{
>>> -	*sizep = 0;
>>> -	return 0;
>>> -}
>>> +static inline void reserve_ibft_region(void) {}
>>>    #endif
>>>    #endif /* ISCSI_IBFT_H */
>> Still no luck Mike,
>>
>> We're back to the original problem where the only thing that worked was to
>> run "SetPageReserved(page)" before calling "kmap(page)". The page is being
>> "freed" before ibft_init() is called as a result of the recent buddy page
>> freeing changes.
> I keep missing some little details each time :(
No worries. Thanks for all your help. Does this patch go on top of your 
previous patch or is it standalone?

George
> Ok, let's try from the different angle.
>
> diff --git a/drivers/acpi/acpica/tbutils.c b/drivers/acpi/acpica/tbutils.c
> index 4b9b329a5a92..ec43e1447336 100644
> --- a/drivers/acpi/acpica/tbutils.c
> +++ b/drivers/acpi/acpica/tbutils.c
> @@ -7,6 +7,8 @@
>    *
>    *****************************************************************************/
>   
> +#include <linux/memblock.h>
> +
>   #include <acpi/acpi.h>
>   #include "accommon.h"
>   #include "actables.h"
> @@ -339,6 +341,21 @@ acpi_tb_parse_root_table(acpi_physical_address rsdp_address)
>   			acpi_tb_parse_fadt();
>   		}
>   
> +		if (ACPI_SUCCESS(status) &&
> +		    ACPI_COMPARE_NAMESEG(&acpi_gbl_root_table_list.
> +					 tables[table_index].signature,
> +					 ACPI_SIG_IBFT)) {
> +			struct acpi_table_header *ibft;
> +			struct acpi_table_desc *desc;
> +
> +			desc = &acpi_gbl_root_table_list.tables[table_index];
> +			status = acpi_tb_get_table(desc, &ibft);
> +			if (ACPI_SUCCESS(status)) {
> +				memblock_reserve(address, ibft->length);
> +				acpi_tb_put_table(desc);
> +			}
> +		}
> +
>   next_table:
>   
>   		table_entry += table_entry_size;
>   
>
>