[PATCH v4] crash utility: fix max_mapnr issue on system has over 44-bit addressing

Jingbai Ma jingbai.ma at hp.com
Wed Oct 16 06:16:10 EDT 2013


The patch will add support for new compressed dumpfile header_version 6.

This bug is 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 */

The old max_mapnr, start_pfn and end_pfn are obsolete, but still be there
for compatibility purpose.

The corresponding patch for makedumpfile can be found here:
http://lists.infradead.org/pipermail/kexec/2013-October/009779.html

Changelog:
v4:
- Fix an invalid condition branch.
- Remove a piece of obsolete code.
- Display the original dh->max_mapnr as it exists in the dumpfile
  header, regardless whether it is the obsolete version or not.
- Change notes for max_mapnr, start_pfn and end_pfn as obsolete.

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 at hp.com>
Tested-by: Lisa Mitchell <lisa.mitchell at hp.com>
---
 diskdump.c |  123 +++++++++++++++++++++++++++++++++++++++++++++++-------------
 diskdump.h |   15 ++++++-
 2 files changed, 108 insertions(+), 30 deletions(-)

diff --git a/diskdump.c b/diskdump.c
index 0819a3f..65e0210 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;
@@ -516,6 +540,13 @@ restart:
 			}
 		}
 		dd->sub_header = sub_header;
+
+		/* 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;
 	} else if (KDUMP_CMPRS_VALID()) {
 		if ((sub_header_kdump = malloc(block_size)) == NULL)
 			error(FATAL, "compressed kdump: cannot malloc sub_header_kdump buffer\n");
@@ -540,8 +571,20 @@ 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;
+		}
 	}
 
+	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;
@@ -571,10 +614,18 @@ restart:
 				DISKDUMP_VALID() ? "diskdump" : "compressed kdump");
 			goto err;
 		}
-		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;
+		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;
 		}
 	}
 
@@ -679,13 +730,13 @@ 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 +778,9 @@ 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 +1086,12 @@ 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 +1110,14 @@ 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");
 		}
@@ -1662,6 +1714,23 @@ __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, "        max_mapnr_64: %llu (0x%llx)\n",
+				kdsh->max_mapnr_64, kdsh->max_mapnr_64);
+		}
 		fprintf(fp, "\n");
 	} else
         	fprintf(fp, "(n/a)\n\n");
@@ -1670,7 +1739,7 @@ __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..88c5be9 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, OBSOLETE!
+						   32bit only, full 64bit
+						   in sub header. */
 	unsigned int		total_ram_blocks;/* Number of blocks should be
 						   written */
 	unsigned int		device_blocks;	/* Number of total blocks in
@@ -61,14 +63,21 @@ 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,
+					       OBSOLETE! 32bit only, full 64bit
+					       in start_pfn_64. */
+	unsigned long	end_pfn;            /* header_version 2 and later,
+					       OBSOLETE! 32bit only, full 64bit
+					       in end_pfn_64. */
 	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 */




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