From c617ec63339222f3a44d73e36677a9acc8954ccd Mon Sep 17 00:00:00 2001

From: John Ogness <john.ogness@linutronix.de>

Date: Thu, 19 Nov 2020 02:41:21 +0000

Subject: [PATCH 1/2] [PATCH 1/2] printk: add support for lockless ringbuffer

* Required for kernel 5.10

Linux 5.10 introduces a new lockless ringbuffer. The new ringbuffer

is structured completely different to the previous iterations.

Add support for retrieving the ringbuffer from debug information

and/or using vmcoreinfo. The new ringbuffer is detected based on

the availability of the "prb" symbol.

Signed-off-by: John Ogness <john.ogness@linutronix.de>

Signed-off-by: Kazuhito Hagio <k-hagio-ab@nec.com>

---

 Makefile       |   2 +-

 dwarf_info.c   |  36 ++++++++-

 makedumpfile.c | 103 +++++++++++++++++++++++-

 makedumpfile.h |  58 ++++++++++++++

 printk.c       | 207 +++++++++++++++++++++++++++++++++++++++++++++++++

 5 files changed, 399 insertions(+), 7 deletions(-)

 create mode 100644 printk.c

diff --git a/makedumpfile-1.6.8/Makefile b/makedumpfile-1.6.8/Makefile

index e5ac71a..cb6bd42 100644

--- a/makedumpfile-1.6.8/Makefile

+++ b/makedumpfile-1.6.8/Makefile

@@ -45,7 +45,7 @@ CFLAGS_ARCH += -m32

 endif

 SRC_BASE = makedumpfile.c makedumpfile.h diskdump_mod.h sadump_mod.h sadump_info.h

-SRC_PART = print_info.c dwarf_info.c elf_info.c erase_info.c sadump_info.c cache.c tools.c

+SRC_PART = print_info.c dwarf_info.c elf_info.c erase_info.c sadump_info.c cache.c tools.c printk.c

 OBJ_PART=$(patsubst %.c,%.o,$(SRC_PART))

 SRC_ARCH = arch/arm.c arch/arm64.c arch/x86.c arch/x86_64.c arch/ia64.c arch/ppc64.c arch/s390x.c arch/ppc.c arch/sparc64.c

 OBJ_ARCH=$(patsubst %.c,%.o,$(SRC_ARCH))

diff --git a/makedumpfile-1.6.8/dwarf_info.c b/makedumpfile-1.6.8/dwarf_info.c

index e42a9f5..543588b 100644

--- a/makedumpfile-1.6.8/dwarf_info.c

+++ b/makedumpfile-1.6.8/dwarf_info.c

@@ -614,6 +614,7 @@ search_structure(Dwarf_Die *die, int *found)

 {

 	int tag;

 	const char *name;

+	Dwarf_Die die_type;

 	/*

 	 * If we get to here then we don't have any more

@@ -622,9 +623,31 @@ search_structure(Dwarf_Die *die, int *found)

 	do {

 		tag  = dwarf_tag(die);

 		name = dwarf_diename(die);

-		if ((tag != DW_TAG_structure_type) || (!name)

-		    || strcmp(name, dwarf_info.struct_name))

+		if ((!name) || strcmp(name, dwarf_info.struct_name))

+			continue;

+

+		if (tag == DW_TAG_typedef) {

+			if (!get_die_type(die, &die_type)) {

+				ERRMSG("Can't get CU die of DW_AT_type.\n");

+				break;

+			}

+

+			/* Resolve typedefs of typedefs. */

+			while ((tag = dwarf_tag(&die_type)) == DW_TAG_typedef) {

+				if (!get_die_type(&die_type, &die_type)) {

+					ERRMSG("Can't get CU die of DW_AT_type.\n");

+					return;

+				}

+			}

+

+			if (tag != DW_TAG_structure_type)

+				continue;

+			die = &die_type;

+

+		} else if (tag != DW_TAG_structure_type) {

 			continue;

+		}

+

 		/*

 		 * Skip if DW_AT_byte_size is not included.

 		 */

@@ -740,6 +763,15 @@ search_typedef(Dwarf_Die *die, int *found)

 				ERRMSG("Can't get CU die of DW_AT_type.\n");

 				break;

 			}

+

+			/* Resolve typedefs of typedefs. */

+			while ((tag = dwarf_tag(&die_type)) == DW_TAG_typedef) {

+				if (!get_die_type(&die_type, &die_type)) {

+					ERRMSG("Can't get CU die of DW_AT_type.\n");

+					return;

+				}

+			}

+

 			dwarf_info.struct_size = dwarf_bytesize(&die_type);

 			if (dwarf_info.struct_size <= 0)

 				continue;

diff --git a/makedumpfile-1.6.8/makedumpfile.c b/makedumpfile-1.6.8/makedumpfile.c

index cdde040..061741f 100644

--- a/makedumpfile-1.6.8/makedumpfile.c

+++ b/makedumpfile-1.6.8/makedumpfile.c

@@ -1555,6 +1555,7 @@ get_symbol_info(void)

 	SYMBOL_INIT(node_data, "node_data");

 	SYMBOL_INIT(pgdat_list, "pgdat_list");

 	SYMBOL_INIT(contig_page_data, "contig_page_data");

+	SYMBOL_INIT(prb, "prb");

 	SYMBOL_INIT(log_buf, "log_buf");

 	SYMBOL_INIT(log_buf_len, "log_buf_len");

 	SYMBOL_INIT(log_end, "log_end");

@@ -1971,16 +1972,47 @@ get_structure_info(void)

 	OFFSET_INIT(elf64_phdr.p_memsz, "elf64_phdr", "p_memsz");

 	SIZE_INIT(printk_log, "printk_log");

-	if (SIZE(printk_log) != NOT_FOUND_STRUCTURE) {

+	SIZE_INIT(printk_ringbuffer, "printk_ringbuffer");

+	if ((SIZE(printk_ringbuffer) != NOT_FOUND_STRUCTURE)) {

+		info->flag_use_printk_ringbuffer = TRUE;

+		info->flag_use_printk_log = FALSE;

+

+		OFFSET_INIT(printk_ringbuffer.desc_ring, "printk_ringbuffer", "desc_ring");

+		OFFSET_INIT(printk_ringbuffer.text_data_ring, "printk_ringbuffer", "text_data_ring");

+

+		OFFSET_INIT(prb_desc_ring.count_bits, "prb_desc_ring", "count_bits");

+		OFFSET_INIT(prb_desc_ring.descs, "prb_desc_ring", "descs");

+		OFFSET_INIT(prb_desc_ring.infos, "prb_desc_ring", "infos");

+		OFFSET_INIT(prb_desc_ring.head_id, "prb_desc_ring", "head_id");

+		OFFSET_INIT(prb_desc_ring.tail_id, "prb_desc_ring", "tail_id");

+

+		SIZE_INIT(prb_desc, "prb_desc");

+		OFFSET_INIT(prb_desc.state_var, "prb_desc", "state_var");

+		OFFSET_INIT(prb_desc.text_blk_lpos, "prb_desc", "text_blk_lpos");

+

+		OFFSET_INIT(prb_data_blk_lpos.begin, "prb_data_blk_lpos", "begin");

+		OFFSET_INIT(prb_data_blk_lpos.next, "prb_data_blk_lpos", "next");

+

+		OFFSET_INIT(prb_data_ring.size_bits, "prb_data_ring", "size_bits");

+		OFFSET_INIT(prb_data_ring.data, "prb_data_ring", "data");

+

+		SIZE_INIT(printk_info, "printk_info");

+		OFFSET_INIT(printk_info.ts_nsec, "printk_info", "ts_nsec");

+		OFFSET_INIT(printk_info.text_len, "printk_info", "text_len");

+

+		OFFSET_INIT(atomic_long_t.counter, "atomic_long_t", "counter");

+	} else if (SIZE(printk_log) != NOT_FOUND_STRUCTURE) {

 		/*

 		 * In kernel 3.11-rc4 the log structure name was renamed

 		 * to "printk_log".

 		 */

+		info->flag_use_printk_ringbuffer = FALSE;

 		info->flag_use_printk_log = TRUE;

 		OFFSET_INIT(printk_log.ts_nsec, "printk_log", "ts_nsec");

 		OFFSET_INIT(printk_log.len, "printk_log", "len");

 		OFFSET_INIT(printk_log.text_len, "printk_log", "text_len");

 	} else {

+		info->flag_use_printk_ringbuffer = FALSE;

 		info->flag_use_printk_log = FALSE;

 		SIZE_INIT(printk_log, "log");

 		OFFSET_INIT(printk_log.ts_nsec, "log", "ts_nsec");

@@ -2191,6 +2223,7 @@ write_vmcoreinfo_data(void)

 	WRITE_SYMBOL("node_data", node_data);

 	WRITE_SYMBOL("pgdat_list", pgdat_list);

 	WRITE_SYMBOL("contig_page_data", contig_page_data);

+	WRITE_SYMBOL("prb", prb);

 	WRITE_SYMBOL("log_buf", log_buf);

 	WRITE_SYMBOL("log_buf_len", log_buf_len);

 	WRITE_SYMBOL("log_end", log_end);

@@ -2222,7 +2255,11 @@ write_vmcoreinfo_data(void)

 	WRITE_STRUCTURE_SIZE("node_memblk_s", node_memblk_s);

 	WRITE_STRUCTURE_SIZE("nodemask_t", nodemask_t);

 	WRITE_STRUCTURE_SIZE("pageflags", pageflags);

-	if (info->flag_use_printk_log)

+	if (info->flag_use_printk_ringbuffer) {

+		WRITE_STRUCTURE_SIZE("printk_ringbuffer", printk_ringbuffer);

+		WRITE_STRUCTURE_SIZE("prb_desc", prb_desc);

+		WRITE_STRUCTURE_SIZE("printk_info", printk_info);

+	} else if (info->flag_use_printk_log)

 		WRITE_STRUCTURE_SIZE("printk_log", printk_log);

 	else

 		WRITE_STRUCTURE_SIZE("log", printk_log);

@@ -2268,7 +2305,30 @@ write_vmcoreinfo_data(void)

 	WRITE_MEMBER_OFFSET("vm_struct.addr", vm_struct.addr);

 	WRITE_MEMBER_OFFSET("vmap_area.va_start", vmap_area.va_start);

 	WRITE_MEMBER_OFFSET("vmap_area.list", vmap_area.list);

-	if (info->flag_use_printk_log) {

+	if (info->flag_use_printk_ringbuffer) {

+		WRITE_MEMBER_OFFSET("printk_ringbuffer.desc_ring", printk_ringbuffer.desc_ring);

+		WRITE_MEMBER_OFFSET("printk_ringbuffer.text_data_ring", printk_ringbuffer.text_data_ring);

+

+		WRITE_MEMBER_OFFSET("prb_desc_ring.count_bits", prb_desc_ring.count_bits);

+		WRITE_MEMBER_OFFSET("prb_desc_ring.descs", prb_desc_ring.descs);

+		WRITE_MEMBER_OFFSET("prb_desc_ring.infos", prb_desc_ring.infos);

+		WRITE_MEMBER_OFFSET("prb_desc_ring.head_id", prb_desc_ring.head_id);

+		WRITE_MEMBER_OFFSET("prb_desc_ring.tail_id", prb_desc_ring.tail_id);

+

+		WRITE_MEMBER_OFFSET("prb_desc.state_var", prb_desc.state_var);

+		WRITE_MEMBER_OFFSET("prb_desc.text_blk_lpos", prb_desc.text_blk_lpos);

+

+		WRITE_MEMBER_OFFSET("prb_data_blk_lpos.begin", prb_data_blk_lpos.begin);

+		WRITE_MEMBER_OFFSET("prb_data_blk_lpos.next", prb_data_blk_lpos.next);

+

+		WRITE_MEMBER_OFFSET("prb_data_ring.size_bits", prb_data_ring.size_bits);

+		WRITE_MEMBER_OFFSET("prb_data_ring.data", prb_data_ring.data);

+

+		WRITE_MEMBER_OFFSET("printk_info.ts_nsec", printk_info.ts_nsec);

+		WRITE_MEMBER_OFFSET("printk_info.text_len", printk_info.text_len);

+

+		WRITE_MEMBER_OFFSET("atomic_long_t.counter", atomic_long_t.counter);

+	} else if (info->flag_use_printk_log) {

 		WRITE_MEMBER_OFFSET("printk_log.ts_nsec", printk_log.ts_nsec);

 		WRITE_MEMBER_OFFSET("printk_log.len", printk_log.len);

 		WRITE_MEMBER_OFFSET("printk_log.text_len", printk_log.text_len);

@@ -2606,6 +2666,7 @@ read_vmcoreinfo(void)

 	READ_SYMBOL("node_data", node_data);

 	READ_SYMBOL("pgdat_list", pgdat_list);

 	READ_SYMBOL("contig_page_data", contig_page_data);

+	READ_SYMBOL("prb", prb);

 	READ_SYMBOL("log_buf", log_buf);

 	READ_SYMBOL("log_buf_len", log_buf_len);

 	READ_SYMBOL("log_end", log_end);

@@ -2684,12 +2745,43 @@ read_vmcoreinfo(void)

 	READ_MEMBER_OFFSET("cpu_spec.mmu_features", cpu_spec.mmu_features);

 	READ_STRUCTURE_SIZE("printk_log", printk_log);

-	if (SIZE(printk_log) != NOT_FOUND_STRUCTURE) {

+	READ_STRUCTURE_SIZE("printk_ringbuffer", printk_ringbuffer);

+	if (SIZE(printk_ringbuffer) != NOT_FOUND_STRUCTURE) {

+		info->flag_use_printk_ringbuffer = TRUE;

+		info->flag_use_printk_log = FALSE;

+

+		READ_MEMBER_OFFSET("printk_ringbuffer.desc_ring", printk_ringbuffer.desc_ring);

+		READ_MEMBER_OFFSET("printk_ringbuffer.text_data_ring", printk_ringbuffer.text_data_ring);

+

+		READ_MEMBER_OFFSET("prb_desc_ring.count_bits", prb_desc_ring.count_bits);

+		READ_MEMBER_OFFSET("prb_desc_ring.descs", prb_desc_ring.descs);

+		READ_MEMBER_OFFSET("prb_desc_ring.infos", prb_desc_ring.infos);

+		READ_MEMBER_OFFSET("prb_desc_ring.head_id", prb_desc_ring.head_id);

+		READ_MEMBER_OFFSET("prb_desc_ring.tail_id", prb_desc_ring.tail_id);

+

+		READ_STRUCTURE_SIZE("prb_desc", prb_desc);

+		READ_MEMBER_OFFSET("prb_desc.state_var", prb_desc.state_var);

+		READ_MEMBER_OFFSET("prb_desc.text_blk_lpos", prb_desc.text_blk_lpos);

+

+		READ_MEMBER_OFFSET("prb_data_blk_lpos.begin", prb_data_blk_lpos.begin);

+		READ_MEMBER_OFFSET("prb_data_blk_lpos.next", prb_data_blk_lpos.next);

+

+		READ_MEMBER_OFFSET("prb_data_ring.size_bits", prb_data_ring.size_bits);

+		READ_MEMBER_OFFSET("prb_data_ring.data", prb_data_ring.data);

+

+		READ_STRUCTURE_SIZE("printk_info", printk_info);

+		READ_MEMBER_OFFSET("printk_info.ts_nsec", printk_info.ts_nsec);

+		READ_MEMBER_OFFSET("printk_info.text_len", printk_info.text_len);

+

+		READ_MEMBER_OFFSET("atomic_long_t.counter", atomic_long_t.counter);

+	} else if (SIZE(printk_log) != NOT_FOUND_STRUCTURE) {

+		info->flag_use_printk_ringbuffer = FALSE;

 		info->flag_use_printk_log = TRUE;

 		READ_MEMBER_OFFSET("printk_log.ts_nsec", printk_log.ts_nsec);

 		READ_MEMBER_OFFSET("printk_log.len", printk_log.len);

 		READ_MEMBER_OFFSET("printk_log.text_len", printk_log.text_len);

 	} else {

+		info->flag_use_printk_ringbuffer = FALSE;

 		info->flag_use_printk_log = FALSE;

 		READ_STRUCTURE_SIZE("log", printk_log);

 		READ_MEMBER_OFFSET("log.ts_nsec", printk_log.ts_nsec);

@@ -5286,6 +5378,9 @@ dump_dmesg()

 	if (!initial())

 		return FALSE;

+	if ((SYMBOL(prb) != NOT_FOUND_SYMBOL))

+		return dump_lockless_dmesg();

+

 	if ((SYMBOL(log_buf) == NOT_FOUND_SYMBOL)

 	    || (SYMBOL(log_buf_len) == NOT_FOUND_SYMBOL)) {

 		ERRMSG("Can't find some symbols for log_buf.\n");

diff --git a/makedumpfile-1.6.8/makedumpfile.h b/makedumpfile-1.6.8/makedumpfile.h

index 698c054..47f7e79 100644

--- a/makedumpfile-1.6.8/makedumpfile.h

+++ b/makedumpfile-1.6.8/makedumpfile.h

@@ -1317,6 +1317,7 @@ struct DumpInfo {

 	int             flag_partial_dmesg;  /* dmesg dump only from the last cleared index*/

 	int             flag_mem_usage;  /*show the page number of memory in different use*/

 	int		flag_use_printk_log; /* did we read printk_log symbol name? */

+	int		flag_use_printk_ringbuffer; /* using lockless printk ringbuffer? */

 	int		flag_nospace;	     /* the flag of "No space on device" error */

 	int		flag_vmemmap;        /* kernel supports vmemmap address space */

 	int		flag_excludevm;      /* -e - excluding unused vmemmap pages */

@@ -1602,6 +1603,7 @@ struct symbol_table {

 	unsigned long long	node_data;

 	unsigned long long	pgdat_list;

 	unsigned long long	contig_page_data;

+	unsigned long long	prb;

 	unsigned long long	log_buf;

 	unsigned long long	log_buf_len;

 	unsigned long long	log_end;

@@ -1689,6 +1691,13 @@ struct size_table {

 	long	nodemask_t;

 	long	printk_log;

+	/*

+	 * for lockless printk ringbuffer

+	 */

+	long	printk_ringbuffer;

+	long	prb_desc;

+	long	printk_info;

+

 	/*

 	 * for Xen extraction

 	 */

@@ -1864,6 +1873,52 @@ struct offset_table {

 		long text_len;

 	} printk_log;

+	/*

+	 * for lockless printk ringbuffer

+	 */

+	struct printk_ringbuffer_s {

+		long desc_ring;

+		long text_data_ring;

+		long fail;

+	} printk_ringbuffer;

+

+	struct prb_desc_ring_s {

+		long count_bits;

+		long descs;

+		long infos;

+		long head_id;

+		long tail_id;

+	} prb_desc_ring;

+

+	struct prb_desc_s {

+		long state_var;

+		long text_blk_lpos;

+	} prb_desc;

+

+	struct prb_data_blk_lpos_s {

+		long begin;

+		long next;

+	} prb_data_blk_lpos;

+

+	struct printk_info_s {

+		long seq;

+		long ts_nsec;

+		long text_len;

+		long caller_id;

+		long dev_info;

+	} printk_info;

+

+	struct prb_data_ring_s {

+		long size_bits;

+		long data;

+		long head_lpos;

+		long tail_lpos;

+	} prb_data_ring;

+

+	struct atomic_long_t_s {

+		long counter;

+	} atomic_long_t;

+

 	/*

 	 * symbols on ppc64 arch

 	 */

@@ -2390,4 +2445,7 @@ int hexadecimal(char *s, int count);

 int decimal(char *s, int count);

 int file_exists(char *file);

+int open_dump_file(void);

+int dump_lockless_dmesg(void);

+

 #endif /* MAKEDUMPFILE_H */

diff --git a/makedumpfile-1.6.8/printk.c b/makedumpfile-1.6.8/printk.c

new file mode 100644

index 0000000..acffb6c

--- /dev/null

+++ b/makedumpfile-1.6.8/printk.c

@@ -0,0 +1,207 @@

+#include "makedumpfile.h"

+#include <ctype.h>

+

+#define DESC_SV_BITS		(sizeof(unsigned long) * 8)

+#define DESC_COMMITTED_MASK	(1UL << (DESC_SV_BITS - 1))

+#define DESC_REUSE_MASK		(1UL << (DESC_SV_BITS - 2))

+#define DESC_FLAGS_MASK		(DESC_COMMITTED_MASK | DESC_REUSE_MASK)

+#define DESC_ID_MASK		(~DESC_FLAGS_MASK)

+

+/* convenience struct for passing many values to helper functions */

+struct prb_map {

+	char		*prb;

+

+	char		*desc_ring;

+	unsigned long	desc_ring_count;

+	char		*descs;

+	char		*infos;

+

+	char		*text_data_ring;

+	unsigned long	text_data_ring_size;

+	char		*text_data;

+};

+

+static void

+dump_record(struct prb_map *m, unsigned long id)

+{

+	unsigned long long ts_nsec;

+	unsigned long state_var;

+	unsigned short text_len;

+	unsigned long begin;

+	unsigned long next;

+	char buf[BUFSIZE];

+	ulonglong nanos;

+	int indent_len;

+	int buf_need;

+	char *bufp;

+	char *text;

+	char *desc;

+	char *inf;

+	ulong rem;

+	char *p;

+	int i;

+

+	desc = m->descs + ((id % m->desc_ring_count) * SIZE(prb_desc));

+

+	/* skip non-committed record */

+	state_var = ULONG(desc + OFFSET(prb_desc.state_var) + OFFSET(atomic_long_t.counter));

+	if ((state_var & DESC_FLAGS_MASK) != DESC_COMMITTED_MASK)

+		return;

+

+	begin = ULONG(desc + OFFSET(prb_desc.text_blk_lpos) + OFFSET(prb_data_blk_lpos.begin)) %

+			m->text_data_ring_size;

+	next = ULONG(desc + OFFSET(prb_desc.text_blk_lpos) + OFFSET(prb_data_blk_lpos.next)) %

+			m->text_data_ring_size;

+

+	/* skip data-less text blocks */

+	if (begin == next)

+		return;

+

+	inf = m->infos + ((id % m->desc_ring_count) * SIZE(printk_info));

+

+	text_len = USHORT(inf + OFFSET(printk_info.text_len));

+

+	/* handle wrapping data block */

+	if (begin > next)

+		begin = 0;

+

+	/* skip over descriptor ID */

+	begin += sizeof(unsigned long);

+

+	/* handle truncated messages */

+	if (next - begin < text_len)

+		text_len = next - begin;

+

+	text = m->text_data + begin;

+

+	ts_nsec = ULONGLONG(inf + OFFSET(printk_info.ts_nsec));

+	nanos = (ulonglong)ts_nsec / (ulonglong)1000000000;

+	rem = (ulonglong)ts_nsec % (ulonglong)1000000000;

+

+	bufp = buf;

+	bufp += sprintf(buf, "[%5lld.%06ld] ", nanos, rem/1000);

+	indent_len = strlen(buf);

+

+	/* How much buffer space is needed in the worst case */

+	buf_need = MAX(sizeof("\\xXX\n"), sizeof("\n") + indent_len);

+

+	for (i = 0, p = text; i < text_len; i++, p++) {

+		if (bufp - buf >= sizeof(buf) - buf_need) {

+			if (write(info->fd_dumpfile, buf, bufp - buf) < 0)

+				return;

+			bufp = buf;

+		}

+

+		if (*p == '\n')

+			bufp += sprintf(bufp, "\n%-*s", indent_len, "");

+		else if (isprint(*p) || isspace(*p))

+			*bufp++ = *p;

+		else

+			bufp += sprintf(bufp, "\\x%02x", *p);

+	}

+

+	*bufp++ = '\n';

+

+	write(info->fd_dumpfile, buf, bufp - buf);

+}

+

+int

+dump_lockless_dmesg(void)

+{

+	unsigned long head_id;

+	unsigned long tail_id;

+	unsigned long kaddr;

+	unsigned long id;

+	struct prb_map m;

+	int ret = FALSE;

+

+	/* setup printk_ringbuffer */

+	if (!readmem(VADDR, SYMBOL(prb), &kaddr, sizeof(kaddr))) {

+		ERRMSG("Can't get the prb address.\n");

+		return ret;

+	}

+

+	m.prb = malloc(SIZE(printk_ringbuffer));

+	if (!m.prb) {

+		ERRMSG("Can't allocate memory for prb.\n");

+		return ret;

+	}

+	if (!readmem(VADDR, kaddr, m.prb, SIZE(printk_ringbuffer))) {

+		ERRMSG("Can't get prb.\n");

+		goto out_prb;

+	}

+

+	/* setup descriptor ring */

+	m.desc_ring = m.prb + OFFSET(printk_ringbuffer.desc_ring);

+	m.desc_ring_count = 1 << UINT(m.desc_ring + OFFSET(prb_desc_ring.count_bits));

+

+	kaddr = ULONG(m.desc_ring + OFFSET(prb_desc_ring.descs));

+	m.descs = malloc(SIZE(prb_desc) * m.desc_ring_count);

+	if (!m.descs) {

+		ERRMSG("Can't allocate memory for prb.desc_ring.descs.\n");

+		goto out_prb;

+	}

+	if (!readmem(VADDR, kaddr, m.descs,

+		     SIZE(prb_desc) * m.desc_ring_count)) {

+		ERRMSG("Can't get prb.desc_ring.descs.\n");

+		goto out_descs;

+	}

+

+	kaddr = ULONG(m.desc_ring + OFFSET(prb_desc_ring.infos));

+	m.infos = malloc(SIZE(printk_info) * m.desc_ring_count);

+	if (!m.infos) {

+		ERRMSG("Can't allocate memory for prb.desc_ring.infos.\n");

+		goto out_descs;

+	}

+	if (!readmem(VADDR, kaddr, m.infos, SIZE(printk_info) * m.desc_ring_count)) {

+		ERRMSG("Can't get prb.desc_ring.infos.\n");

+		goto out_infos;

+	}

+

+	/* setup text data ring */

+	m.text_data_ring = m.prb + OFFSET(printk_ringbuffer.text_data_ring);

+	m.text_data_ring_size = 1 << UINT(m.text_data_ring + OFFSET(prb_data_ring.size_bits));

+

+	kaddr = ULONG(m.text_data_ring + OFFSET(prb_data_ring.data));

+	m.text_data = malloc(m.text_data_ring_size);

+	if (!m.text_data) {

+		ERRMSG("Can't allocate memory for prb.text_data_ring.data.\n");

+		goto out_infos;

+	}

+	if (!readmem(VADDR, kaddr, m.text_data, m.text_data_ring_size)) {

+		ERRMSG("Can't get prb.text_data_ring.\n");

+		goto out_text_data;

+	}

+

+	/* ready to go */

+

+	tail_id = ULONG(m.desc_ring + OFFSET(prb_desc_ring.tail_id) +

+			OFFSET(atomic_long_t.counter));

+	head_id = ULONG(m.desc_ring + OFFSET(prb_desc_ring.head_id) +

+			OFFSET(atomic_long_t.counter));

+

+	if (!open_dump_file()) {

+		ERRMSG("Can't open output file.\n");

+		goto out_text_data;

+	}

+

+	for (id = tail_id; id != head_id; id = (id + 1) & DESC_ID_MASK)

+		dump_record(&m, id);

+

+	/* dump head record */

+	dump_record(&m, id);

+

+	if (!close_files_for_creating_dumpfile())

+		goto out_text_data;

+

+	ret = TRUE;

+out_text_data:

+	free(m.text_data);

+out_infos:

+	free(m.infos);

+out_descs:

+	free(m.descs);

+out_prb:

+	free(m.prb);

+	return ret;

+}

-- 

2.29.2