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

[Mike Rapoport]

On Thu, Feb 25, 2021 at 07:38:19AM -0500, George Kennedy wrote:
> 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?

This is 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;
> > 
> > 
> 

-- 
Sincerely yours,
Mike.