Re: [PATCH v3] crash utility: fix max_mapnr issue on system has over 44-bit addressing

[Jingbai Ma <jingbai.ma@hp.com>]

On 10/16/2013 03:22 AM, Dave Anderson wrote:
>
> Hello Jingbai,
>
> I have a few additional comments below:
>
> ----- Original Message -----
>> The patch will add support for new compressed dumpfile header_version 6.
>>
>> This bug was posted here:
>> http://lists.infradead.org/pipermail/kexec/2013-September/009587.html
>>
>> This patch will add 3 new fields in struct kdump_sub_header.
>> unsigned long long start_pfn_64;  /* header_version 6 and later */
>> unsigned long long end_pfn_64;    /* header_version 6 and later */
>> unsigned long long max_mapnr_64;  /* header_version 6 and later */
>>
>> And the old "unsigned int max_mapnr" in struct disk_dump_header will
>> not be used anymore. But still be there for compatibility purpose.
>>
>> The corresponding patch for makedumpfile can be found here:
>> http://lists.infradead.org/pipermail/kexec/2013-October/009727.html
>>
>> Changelog:
>> v3:
>> - Fix a bug that failed to work with old split format kdumps.
>>
>> v2:
>> - Rename max_mapnr in struct kdump_sub_header to max_mapnr_64.
>> - Change type of max_mapnr_64 from unsigned long to unsigned long long.
>>    In x86 PAE mode on x86_32 kernel, the address may exceeds 44bit limit.
>> - Add start_pfn_64, end_pfn_64 for struct kdump_sub_header.
>> - Add a 64bit max_mapnr in struct diskdump_data. The max_mapnr_64 in
>>    the sub-header only exists in compressed kdump file format, so can't
>>    be used in diskdump file format.
>> - Merge a patch from Dave Anderson that fixed bitmap_len issue.
>>
>> v1:
>> - http://lists.infradead.org/pipermail/kexec/2013-September/009663.html
>>
>> Signed-off-by: Jingbai Ma<jingbai.ma@hp.com>
>> Tested-by: Lisa Mitchell<lisa.mitchell@hp.com>
>> ---
>>   diskdump.c |  122
>>   ++++++++++++++++++++++++++++++++++++++++++++++++------------
>>   diskdump.h |   17 +++++++-
>>   2 files changed, 112 insertions(+), 27 deletions(-)
>>
>> diff --git a/diskdump.c b/diskdump.c
>> index 0819a3f..bb7a33e 100644
>> --- a/diskdump.c
>> +++ b/diskdump.c
>> @@ -40,11 +40,13 @@ struct diskdump_data {
>>   	struct disk_dump_sub_header	*sub_header;
>>   	struct kdump_sub_header		*sub_header_kdump;
>>
>> +	unsigned long long	max_mapnr;	/* 64bit max_mapnr */
>> +
>>   	size_t	data_offset;
>>   	int	block_size;
>>   	int	block_shift;
>>   	char	*bitmap;
>> -	int	bitmap_len;
>> +	off_t	bitmap_len;
>>   	char	*dumpable_bitmap;
>>   	int	byte, bit;
>>   	char	*compressed_page;	/* copy of compressed page data */
>> @@ -170,9 +172,9 @@ add_diskdump_data(char* name)
>>   	dd->filename = name;
>>
>>   	if (CRASHDEBUG(1))
>> -		fprintf(fp, "%s: start_pfn=%lu, end_pfn=%lu\n", name,
>> -			dd->sub_header_kdump->start_pfn,
>> -			dd->sub_header_kdump->end_pfn);
>> +		fprintf(fp, "%s: start_pfn=%llu, end_pfn=%llu\n", name,
>> +			dd->sub_header_kdump->start_pfn_64,
>> +			dd->sub_header_kdump->end_pfn_64);
>>   }
>>
>>   static void
>> @@ -199,13 +201,13 @@ get_bit(char *map, int byte, int bit)
>>   }
>>
>>   static inline int
>> -page_is_ram(unsigned int nr)
>> +page_is_ram(unsigned long nr)
>>   {
>>   	return get_bit(dd->bitmap, nr>>  3, nr&  7);
>>   }
>>
>>   static inline int
>> -page_is_dumpable(unsigned int nr)
>> +page_is_dumpable(unsigned long nr)
>>   {
>>   	return dd->dumpable_bitmap[nr>>3]&  (1<<  (nr&  7));
>>   }
>> @@ -214,7 +216,7 @@ static inline int
>>   dump_is_partial(const struct disk_dump_header *header)
>>   {
>>   	return header->bitmap_blocks>=
>> -	    divideup(divideup(header->max_mapnr, 8), dd->block_size) * 2;
>> +	    divideup(divideup(dd->max_mapnr, 8), dd->block_size) * 2;
>>   }
>>
>>   static int
>> @@ -321,6 +323,9 @@ x86_process_elf_notes(void *note_ptr, unsigned long
>> size_note)
>>    * [40]    unsigned long   size_note;          /  header_version 4 and later
>>    /
>>    * [44]    off_t           offset_eraseinfo;   /  header_version 5 and later
>>    /
>>    * [52]    unsigned long   size_eraseinfo;     /  header_version 5 and later
>>    /
>> + * [56]    unsigned long long   start_pfn_64;  /  header_version 6 and later
>> /
>> + * [64]    unsigned long long   end_pfn_64;    /  header_version 6 and later
>> /
>> + * [72]    unsigned long long   max_mapnr_64;  /  header_version 6 and later
>> /
>>    * };
>>    *
>>    * But when compiled on an ARM processor, each 64-bit "off_t" would be
>>    pushed
>> @@ -337,7 +342,10 @@ x86_process_elf_notes(void *note_ptr, unsigned long
>> size_note)
>>    * [40]    off_t           offset_note;        /  header_version 4 and later
>>    /
>>    * [48]    unsigned long   size_note;          /  header_version 4 and later
>>    /
>>    * [56]    off_t           offset_eraseinfo;   /  header_version 5 and later
>>    /
>> - * [62]    unsigned long   size_eraseinfo;     /  header_version 5 and later
>> /
>> + * [64]    unsigned long   size_eraseinfo;     /  header_version 5 and later
>> /
>> + * [72]    unsigned long long   start_pfn_64;  /  header_version 6 and later
>> /
>> + * [80]    unsigned long long   end_pfn_64;    /  header_version 6 and later
>> /
>> + * [88]    unsigned long long   max_mapnr_64;  /  header_version 6 and later
>> /
>>    * };
>>    *
>>    */
>> @@ -357,6 +365,10 @@ struct kdump_sub_header_ARM_target {
>>   	int 		pad3;
>>           off_t           offset_eraseinfo;   /* header_version 5 and later */
>>           unsigned long   size_eraseinfo;     /* header_version 5 and later */
>> +	int		pad4;
>> +	unsigned long long start_pfn_64;    /* header_version 6 and later */
>> +	unsigned long long end_pfn_64;      /* header_version 6 and later */
>> +	unsigned long long max_mapnr_64;    /* header_version 6 and later */
>>   };
>>
>>   static void
>> @@ -380,6 +392,15 @@ arm_kdump_header_adjust(int header_version)
>>   		kdsh->offset_eraseinfo = kdsh_ARM_target->offset_eraseinfo;
>>   		kdsh->size_eraseinfo = kdsh_ARM_target->size_eraseinfo;
>>   	}
>> +	if (header_version>= 6) {
>> +		kdsh->start_pfn_64 = kdsh_ARM_target->start_pfn_64;
>> +		kdsh->end_pfn_64 = kdsh_ARM_target->end_pfn_64;
>> +		kdsh->max_mapnr_64 = kdsh_ARM_target->map_mapnr_64;
>> +	} else {
>> +		kdsh->start_pfn_64 = kdsh_ARM_target->start_pfn;
>> +		kdsh->end_pfn_64 = kdsh_ARM_target->end_pfn;
>> +		kdsh->max_mapnr_64 = dd->map_mapnr;
>> +	}
>>   }
>>   #endif  /* __i386__&&  ARM */
>>
>> @@ -390,7 +411,10 @@ read_dump_header(char *file)
>>   	struct disk_dump_sub_header *sub_header = NULL;
>>   	struct kdump_sub_header *sub_header_kdump = NULL;
>>   	size_t size;
>> -	int bitmap_len;
>> +	off_t bitmap_len;
>> +	char *bufptr;
>> +	size_t len;
>> +	size_t bytes_read;
>>   	int block_size = (int)sysconf(_SC_PAGESIZE);
>>   	off_t offset;
>>   	const off_t failed = (off_t)-1;
>> @@ -540,8 +564,27 @@ restart:
>>   #if defined(__i386__)&&  defined(ARM)
>>   		arm_kdump_header_adjust(header->header_version);
>>   #endif
>> +		/* use 64bit max_mapnr in compressed kdump file sub-header */
>> +		if (header->header_version>= 6)
>> +			dd->max_mapnr = dd->sub_header_kdump->max_mapnr_64;
>> +		else {
>> +			dd->sub_header_kdump->start_pfn_64
>> +				= dd->sub_header_kdump->start_pfn;
>> +			dd->sub_header_kdump->end_pfn_64
>> +				= dd->sub_header_kdump->end_pfn;
>> +		}
>> +	} else {
>> +		/* the 64bit max_mapnr only exists in sub-header of compressed
>> +		 * kdump file, if it's not a compressed kdump file, we have to
>> +		 * use the old 32bit max_mapnr in dumpfile header.
>> +		 * max_mapnr may be truncated here.
>> +		 */
>> +		 dd->max_mapnr = header->max_mapnr;
>>   	}
>
> The additional "} else {" segment above doesn't make sense because either
> DISKDUMP_VALID() or KDUMP_CMPRS_VALID() are true, so the "else" part will
> never be executed.
>
> The patch works because you follow the above section with this piece:
>
>> +	if (header->header_version<  6)
>> +		dd->max_mapnr = header->max_mapnr;
>> +
>>   	/* read memory bitmap */
>>   	bitmap_len = block_size * header->bitmap_blocks;
>>   	dd->bitmap_len = bitmap_len;
>> @@ -571,11 +614,27 @@ restart:
>>   				DISKDUMP_VALID() ? "diskdump" : "compressed kdump");
>>   			goto err;
>>   		}
>> +#ifdef OLDWAY
>>   		if (read(dd->dfd, dd->bitmap, bitmap_len)<  bitmap_len) {
>>   			error(INFO, "%s: cannot read memory bitmap\n",
>>   				DISKDUMP_VALID() ? "diskdump" : "compressed kdump");
>>   			goto err;
>>   		}
>> +#else
>> +		bufptr = dd->bitmap;
>> +		len = bitmap_len;
>> +		while (len) {
>> +			bytes_read = read(dd->dfd, bufptr, len);
>> +			if (bytes_read<  0) {
>> +				error(INFO, "%s: cannot read memory bitmap\n",
>> +					DISKDUMP_VALID() ? "diskdump"
>> +					: "compressed kdump");
>> +				goto err;
>> +			}
>> +			len -= bytes_read;
>> +			bufptr += bytes_read;
>> +		}
>> +#endif
>
> You can get rid of the "#ifdef OLDWAY" section -- I left that there when
> I gave Lisa my debug version of the function so that the difference would
> be obvious.
>
>>   	}
>>
>>   	if (dump_is_partial(header))
>> @@ -679,13 +738,13 @@ restart:
>>   	}
>>
>>   	if (!is_split) {
>> -		max_sect_len = divideup(header->max_mapnr, BITMAP_SECT_LEN);
>> +		max_sect_len = divideup(dd->max_mapnr, BITMAP_SECT_LEN);
>>   		pfn = 0;
>>   		dd->filename = file;
>>   	}
>>   	else {
>> -		ulong start = sub_header_kdump->start_pfn;
>> -		ulong end = sub_header_kdump->end_pfn;
>> +		unsigned long long start = sub_header_kdump->start_pfn_64;
>> +		unsigned long long end = sub_header_kdump->end_pfn_64;
>>   		max_sect_len = divideup(end - start + 1, BITMAP_SECT_LEN);
>>   		pfn = start;
>>   	}
>> @@ -727,8 +786,9 @@ pfn_to_pos(ulong pfn)
>>   	ulong p1, p2;
>>
>>   	if (KDUMP_SPLIT()) {
>> -		p1 = pfn - dd->sub_header_kdump->start_pfn;
>> -		p2 = round(p1, BITMAP_SECT_LEN) + dd->sub_header_kdump->start_pfn;
>> +		p1 = pfn - dd->sub_header_kdump->start_pfn_64;
>> +		p2 = round(p1, BITMAP_SECT_LEN)
>> +			+ dd->sub_header_kdump->start_pfn_64;
>>   	}
>>   	else {
>>   		p1 = pfn;
>> @@ -1034,12 +1094,12 @@ read_diskdump(int fd, void *bufptr, int cnt, ulong
>> addr, physaddr_t paddr)
>>   	if (KDUMP_SPLIT()) {
>>   		/* Find proper dd */
>>   		int i;
>> -		unsigned long start_pfn;
>> -		unsigned long end_pfn;
>> +		unsigned long long start_pfn;
>> +		unsigned long long end_pfn;
>>
>>   		for (i=0; i<num_dumpfiles; i++) {
>> -			start_pfn = dd_list[i]->sub_header_kdump->start_pfn;
>> -			end_pfn = dd_list[i]->sub_header_kdump->end_pfn;
>> +			start_pfn = dd_list[i]->sub_header_kdump->start_pfn_64;
>> +			end_pfn = dd_list[i]->sub_header_kdump->end_pfn_64;
>>   			if ((pfn>= start_pfn)&&  (pfn<= end_pfn))	{
>>   				dd = dd_list[i];
>>   				break;
>> @@ -1058,14 +1118,14 @@ read_diskdump(int fd, void *bufptr, int cnt, ulong
>> addr, physaddr_t paddr)
>>   	curpaddr = paddr&  ~((physaddr_t)(dd->block_size-1));
>>   	page_offset = paddr&  ((physaddr_t)(dd->block_size-1));
>>
>> -	if ((pfn>= dd->header->max_mapnr) || !page_is_ram(pfn)) {
>> +	if ((pfn>= dd->max_mapnr) || !page_is_ram(pfn)) {
>>   		if (CRASHDEBUG(8)) {
>>   			fprintf(fp, "read_diskdump: SEEK_ERROR: "
>>   			    "paddr/pfn: %llx/%lx ",
>>   				(ulonglong)paddr, pfn);
>> -			if (pfn>= dd->header->max_mapnr)
>> -				fprintf(fp, "max_mapnr: %x\n",
>> -					dd->header->max_mapnr);
>> +			if (pfn>= dd->max_mapnr)
>> +				fprintf(fp, "max_mapnr: %llx\n",
>> +					dd->max_mapnr);
>>   			else
>>   				fprintf(fp, "!page_is_ram\n");
>>   		}
>> @@ -1517,7 +1577,7 @@ __diskdump_memory_dump(FILE *fp)
>>   	fprintf(fp, "          block_size: %d\n", dh->block_size);
>>   	fprintf(fp, "        sub_hdr_size: %d\n", dh->sub_hdr_size);
>>   	fprintf(fp, "       bitmap_blocks: %u\n", dh->bitmap_blocks);
>> -	fprintf(fp, "           max_mapnr: %u\n", dh->max_mapnr);
>> +	fprintf(fp, "           max_mapnr: %llu\n", dd->max_mapnr);
>
> Please display the original dh->max_mapnr as it exists in the dumpfile
> header, regardless whether it is the obsolete version or not.
>
> Your new "dd->max_mapnr" should be displayed further down in the function
> where the other diskdump_data fields are shown.
>
>>   	fprintf(fp, "    total_ram_blocks: %u\n", dh->total_ram_blocks);
>>   	fprintf(fp, "       device_blocks: %u\n", dh->device_blocks);
>>   	fprintf(fp, "      written_blocks: %u\n", dh->written_blocks);
>> @@ -1662,6 +1722,20 @@ __diskdump_memory_dump(FILE *fp)
>>   				dump_eraseinfo(fp);
>>   			}
>>   		}
>> +		if (dh->header_version>= 6) {
>> +			fprintf(fp, "           start_pfn_64: ");
>> +			if (KDUMP_SPLIT())
>> +				fprintf(fp, "%lld (0x%llx)\n",
>> +					kdsh->start_pfn_64, kdsh->start_pfn_64);
>> +			else
>> +				fprintf(fp, "(unused)\n");
>> +			fprintf(fp, "             end_pfn_64: ");
>> +			if (KDUMP_SPLIT())
>> +				fprintf(fp, "%lld (0x%llx)\n",
>> +					kdsh->end_pfn_64, kdsh->end_pfn_64);
>> +			else
>> +				fprintf(fp, "(unused)\n");
>> +		}
>>   		fprintf(fp, "\n");
>>   	} else
>>           	fprintf(fp, "(n/a)\n\n");
>> @@ -1670,7 +1744,7 @@ __diskdump_memory_dump(FILE *fp)
>>   	fprintf(fp, "        block_size: %d\n", dd->block_size);
>>   	fprintf(fp, "       block_shift: %d\n", dd->block_shift);
>>   	fprintf(fp, "            bitmap: %lx\n", (ulong)dd->bitmap);
>> -	fprintf(fp, "        bitmap_len: %d\n", dd->bitmap_len);
>> +	fprintf(fp, "        bitmap_len: %ld\n", dd->bitmap_len);
>>   	fprintf(fp, "   dumpable_bitmap: %lx\n", (ulong)dd->dumpable_bitmap);
>>   	fprintf(fp, "              byte: %d\n", dd->byte);
>>   	fprintf(fp, "               bit: %d\n", dd->bit);
>> diff --git a/diskdump.h b/diskdump.h
>> index 9ab10b6..0492351 100644
>> --- a/diskdump.h
>> +++ b/diskdump.h
>> @@ -42,7 +42,9 @@ struct disk_dump_header {
>>   						   header in blocks */
>>   	unsigned int		bitmap_blocks;	/* Size of Memory bitmap in
>>   						   block */
>> -	unsigned int		max_mapnr;	/* = max_mapnr */
>> +	unsigned int		max_mapnr;	/* = max_mapnr, 32bit only,
>> +						   full 64bit in sub header.
>> +						   Do NOT use this anymore! */
>
> You can change this comment to read "obsolete" so that it is similar to Daisuke's
> suggestion for makedumpfile.
>
>>   	unsigned int		total_ram_blocks;/* Number of blocks should be
>>   						   written */
>>   	unsigned int		device_blocks;	/* Number of total blocks in
>> @@ -61,14 +63,23 @@ struct kdump_sub_header {
>>   	unsigned long	phys_base;
>>   	int		dump_level;         /* header_version 1 and later */
>>   	int		split;              /* header_version 2 and later */
>> -	unsigned long	start_pfn;          /* header_version 2 and later */
>> -	unsigned long	end_pfn;            /* header_version 2 and later */
>> +	unsigned long	start_pfn;          /* header_version 2 and later,
>> +					       32bit only, full 64bit in
>> +					       start_pfn_64.
>> +					       Do not use this anymore! */
>> +	unsigned long	end_pfn;            /* header_version 2 and later,
>> +					       32bit only, full 64bit in
>> +					       end_pfn_64.
>
> Same here...
>
>> +					       Do not use this anymore! */
>>   	off_t		offset_vmcoreinfo;  /* header_version 3 and later */
>>   	unsigned long	size_vmcoreinfo;    /* header_version 3 and later */
>>   	off_t		offset_note;        /* header_version 4 and later */
>>   	unsigned long	size_note;          /* header_version 4 and later */
>>   	off_t		offset_eraseinfo;   /* header_version 5 and later */
>>   	unsigned long	size_eraseinfo;     /* header_version 5 and later */
>> +	unsigned long long start_pfn_64;    /* header_version 6 and later */
>> +	unsigned long long end_pfn_64;      /* header_version 6 and later */
>> +	unsigned long long max_mapnr_64;    /* header_version 6 and later */
>>   };
>>
>>   /* page flags */
>
> Thanks,
>    Dave
>
>

I will fix all these issues and send out a new patch.
Thanks!


-- 
Thanks,
Jingbai Ma

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