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Subject: Re: [PATCH] mm, kasan: don't poison boot memory
To:     Mike Rapoport <rppt@linux.ibm.com>
Cc:     David Hildenbrand <david@redhat.com>,
        Andrey Konovalov <andreyknvl@google.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Vincenzo Frascino <vincenzo.frascino@arm.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Konrad Rzeszutek Wilk <konrad@darnok.org>,
        Will Deacon <will.deacon@arm.com>,
        Andrey Ryabinin <aryabinin@virtuozzo.com>,
        Alexander Potapenko <glider@google.com>,
        Marco Elver <elver@google.com>,
        Peter Collingbourne <pcc@google.com>,
        Evgenii Stepanov <eugenis@google.com>,
        Branislav Rankov <Branislav.Rankov@arm.com>,
        Kevin Brodsky <kevin.brodsky@arm.com>,
        Christoph Hellwig <hch@infradead.org>,
        kasan-dev <kasan-dev@googlegroups.com>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        Linux Memory Management List <linux-mm@kvack.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Dhaval Giani <dhaval.giani@oracle.com>
References: <20210223154758.GF1741768@linux.ibm.com>
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From:   George Kennedy <george.kennedy@oracle.com>
Organization: Oracle Corporation
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Date:   Thu, 25 Feb 2021 10:22:44 -0500
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On 2/25/2021 9:57 AM, Mike Rapoport wrote:
> 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;
>>>
>>>
Applied just your latest patch, but same failure.

I thought there was an earlier comment (which I can't find now) that 
stated that memblock_reserve() wouldn't reserve the page, which is 
what's needed here.

[   30.308229] iBFT detected..
[   30.308796] 
==================================================================
[   30.308890] BUG: KASAN: use-after-free in ibft_init+0x134/0xc33
[   30.308890] Read of size 4 at addr ffff8880be453004 by task swapper/0/1
[   30.308890]
[   30.308890] CPU: 1 PID: 1 Comm: swapper/0 Not tainted 5.11.0-f9593a0 #12
[   30.308890] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), 
BIOS 0.0.0 02/06/2015
[   30.308890] Call Trace:
[   30.308890]  dump_stack+0xdb/0x120
[   30.308890]  ? ibft_init+0x134/0xc33
[   30.308890]  print_address_description.constprop.7+0x41/0x60
[   30.308890]  ? ibft_init+0x134/0xc33
[   30.308890]  ? ibft_init+0x134/0xc33
[   30.308890]  kasan_report.cold.10+0x78/0xd1
[   30.308890]  ? ibft_init+0x134/0xc33
[   30.308890]  __asan_report_load_n_noabort+0xf/0x20
[   30.308890]  ibft_init+0x134/0xc33
[   30.308890]  ? write_comp_data+0x2f/0x90
[   30.308890]  ? ibft_check_initiator_for+0x159/0x159
[   30.308890]  ? write_comp_data+0x2f/0x90
[   30.308890]  ? ibft_check_initiator_for+0x159/0x159
[   30.308890]  do_one_initcall+0xc4/0x3e0
[   30.308890]  ? perf_trace_initcall_level+0x3e0/0x3e0
[   30.308890]  ? unpoison_range+0x14/0x40
[   30.308890]  ? ____kasan_kmalloc.constprop.5+0x8f/0xc0
[   30.308890]  ? kernel_init_freeable+0x420/0x652
[   30.308890]  ? __kasan_kmalloc+0x9/0x10
[   30.308890]  ? __sanitizer_cov_trace_pc+0x21/0x50
[   30.308890]  kernel_init_freeable+0x596/0x652
[   30.308890]  ? console_on_rootfs+0x7d/0x7d
[   30.308890]  ? __sanitizer_cov_trace_pc+0x21/0x50
[   30.308890]  ? rest_init+0xf0/0xf0
[   30.308890]  kernel_init+0x16/0x1d0
[   30.308890]  ? rest_init+0xf0/0xf0
[   30.308890]  ret_from_fork+0x22/0x30
[   30.308890]
[   30.308890] The buggy address belongs to the page:
[   30.308890] page:0000000001b7b17c refcount:0 mapcount:0 
mapping:0000000000000000 index:0x1 pfn:0xbe453
[   30.308890] flags: 0xfffffc0000000()
[   30.308890] raw: 000fffffc0000000 ffffea0002ef9788 ffffea0002f91488 
0000000000000000
[   30.308890] raw: 0000000000000001 0000000000000000 00000000ffffffff 
0000000000000000
[   30.308890] page dumped because: kasan: bad access detected
[   30.308890] page_owner tracks the page as freed
[   30.308890] page last allocated via order 0, migratetype Movable, 
gfp_mask 0x100dca(GFP_HIGHUSER_MOVABLE|__GFP_ZERO), pid 204, ts 28121288605
[   30.308890]  prep_new_page+0xfb/0x140
[   30.308890]  get_page_from_freelist+0x3503/0x5730
[   30.308890]  __alloc_pages_nodemask+0x2d8/0x650
[   30.308890]  alloc_pages_vma+0xe2/0x560
[   30.308890]  __handle_mm_fault+0x930/0x26c0
[   30.308890]  handle_mm_fault+0x1f9/0x810
[   30.308890]  do_user_addr_fault+0x6f7/0xca0
[   30.308890]  exc_page_fault+0xaf/0x1a0
[   30.308890]  asm_exc_page_fault+0x1e/0x30
[   30.308890] page last free stack trace:
[   30.308890]  free_pcp_prepare+0x122/0x290
[   30.308890]  free_unref_page_list+0xe6/0x490
[   30.308890]  release_pages+0x2ed/0x1270
[   30.308890]  free_pages_and_swap_cache+0x245/0x2e0
[   30.308890]  tlb_flush_mmu+0x11e/0x680
[   30.308890]  tlb_finish_mmu+0xa6/0x3e0
[   30.308890]  exit_mmap+0x2b3/0x540
[   30.308890]  mmput+0x11d/0x450
[   30.308890]  do_exit+0xaa6/0x2d40
[   30.308890]  do_group_exit+0x128/0x340
[   30.308890]  __x64_sys_exit_group+0x43/0x50
[   30.308890]  do_syscall_64+0x37/0x50
[   30.308890]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[   30.308890]
[   30.308890] Memory state around the buggy address:
[   30.308890]  ffff8880be452f00: ff ff ff ff ff ff ff ff ff ff ff ff ff 
ff ff ff
[   30.308890]  ffff8880be452f80: ff ff ff ff ff ff ff ff ff ff ff ff ff 
ff ff ff
[   30.308890] >ffff8880be453000: ff ff ff ff ff ff ff ff ff ff ff ff ff 
ff ff ff
[   30.308890]                    ^
[   30.308890]  ffff8880be453080: ff ff ff ff ff ff ff ff ff ff ff ff ff 
ff ff ff
[   30.308890]  ffff8880be453100: ff ff ff ff ff ff ff ff ff ff ff ff ff 
ff ff ff
[   30.308890] 
==================================================================

George