Re: PROBLEM: 2.6.13, Inconsistent kallsyms data

Paulo Marques
2005-08-31T14:36:47Z

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Jim McCloskey wrote:
> When I try to compile 2.6.13, using a complete tarball from
> kernel.org, the compilation fails with:
>
> -----------------------------------------------------------
> SYSMAP System.map
> SYSMAP .tmp_System.map
> Inconsistent kallsyms data
> Try setting CONFIG_KALLSYMS_EXTRA_PASS
> make: *** [vmlinux] Error 1
> -----------------------------------------------------------
>
> When CONFIG_KALLSYMS_EXTRA_PASS is set, the compilation completes
> successfully.

Please try the attached patch too see if it fixes the problem for you.

This patch is already in -mm and scheduled to go in 2.6.14 (or at least
I hope it is ;)

--
Paulo Marques - www.grupopie.com

It is a mistake to think you can solve any major problems
just with potatoes.
Douglas Adams

[-- Attachment #2: kallsyms_patch --]
[-- Type: text/plain, Size: 17273 bytes --]

--- ./scripts/kallsyms.c.orig 2005-06-23 19:20:20.000000000 +0100
+++ ./scripts/kallsyms.c 2005-06-23 19:20:34.000000000 +0100
@@ -24,75 +24,37 @@
*
*/

+#define _GNU_SOURCE
+
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>

-/* maximum token length used. It doesn't pay to increase it a lot, because
- * very long substrings probably don't repeat themselves too often. */
-#define MAX_TOK_SIZE 11
#define KSYM_NAME_LEN 127

-/* we use only a subset of the complete symbol table to gather the token count,
- * to speed up compression, at the expense of a little compression ratio */
-#define WORKING_SET 1024
-
-/* first find the best token only on the list of tokens that would profit more
- * than GOOD_BAD_THRESHOLD. Only if this list is empty go to the "bad" list.
- * Increasing this value will put less tokens on the "good" list, so the search
- * is faster. However, if the good list runs out of tokens, we must painfully
- * search the bad list. */
-#define GOOD_BAD_THRESHOLD 10
-
-/* token hash parameters */
-#define HASH_BITS 18
-#define HASH_TABLE_SIZE (1 << HASH_BITS)
-#define HASH_MASK (HASH_TABLE_SIZE - 1)
-#define HASH_BASE_OFFSET 2166136261U
-#define HASH_FOLD(a) ((a)&(HASH_MASK))
-
-/* flags to mark symbols */
-#define SYM_FLAG_VALID 1
-#define SYM_FLAG_SAMPLED 2

struct sym_entry {
unsigned long long addr;
- char type;
- unsigned char flags;
- unsigned char len;
+ unsigned int len;
unsigned char *sym;
};

static struct sym_entry *table;
-static int size, cnt;
+static unsigned int table_size, table_cnt;
static unsigned long long _stext, _etext, _sinittext, _einittext, _sextratext, _eextratext;
static int all_symbols = 0;
static char symbol_prefix_char = '\0';

-struct token {
- unsigned char data[MAX_TOK_SIZE];
- unsigned char len;
- /* profit: the number of bytes that could be saved by inserting this
- * token into the table */
- int profit;
- struct token *next; /* next token on the hash list */
- struct token *right; /* next token on the good/bad list */
- struct token *left; /* previous token on the good/bad list */
- struct token *smaller; /* token that is less one letter than this one */
- };
-
-struct token bad_head, good_head;
-struct token *hash_table[HASH_TABLE_SIZE];
+int token_profit[0x10000];

/* the table that holds the result of the compression */
-unsigned char best_table[256][MAX_TOK_SIZE+1];
+unsigned char best_table[256][2];
unsigned char best_table_len[256];

-static void
-usage(void)
+static void usage(void)
{
fprintf(stderr, "Usage: kallsyms [--all-symbols] [--symbol-prefix=<prefix char>] < in.map > out.S\n");
exit(1);
@@ -102,21 +64,19 @@ usage(void)
* This ignores the intensely annoying "mapping symbols" found
* in ARM ELF files: $a, $t and $d.
*/
-static inline int
-is_arm_mapping_symbol(const char *str)
+static inline int is_arm_mapping_symbol(const char *str)
{
return str[0] == '$' && strchr("atd", str[1])
&& (str[2] == '\0' || str[2] == '.');
}

-static int
-read_symbol(FILE *in, struct sym_entry *s)
+static int read_symbol(FILE *in, struct sym_entry *s)
{
char str[500];
- char *sym;
+ char *sym, stype;
int rc;

- rc = fscanf(in, "%llx %c %499s\n", &s->addr, &s->type, str);
+ rc = fscanf(in, "%llx %c %499s\n", &s->addr, &stype, str);
if (rc != 3) {
if (rc != EOF) {
/* skip line */
@@ -143,7 +103,7 @@ read_symbol(FILE *in, struct sym_entry *
_sextratext = s->addr;
else if (strcmp(sym, "_eextratext") == 0)
_eextratext = s->addr;
- else if (toupper(s->type) == 'A')
+ else if (toupper(stype) == 'A')
{
/* Keep these useful absolute symbols */
if (strcmp(sym, "__kernel_syscall_via_break") &&
@@ -153,22 +113,21 @@ read_symbol(FILE *in, struct sym_entry *
return -1;

}
- else if (toupper(s->type) == 'U' ||
+ else if (toupper(stype) == 'U' ||
is_arm_mapping_symbol(sym))
return -1;

/* include the type field in the symbol name, so that it gets
* compressed together */
s->len = strlen(str) + 1;
- s->sym = (char *) malloc(s->len + 1);
- strcpy(s->sym + 1, str);
- s->sym[0] = s->type;
+ s->sym = malloc(s->len + 1);
+ strcpy((char *)s->sym + 1, str);
+ s->sym[0] = stype;

return 0;
}

-static int
-symbol_valid(struct sym_entry *s)
+static int symbol_valid(struct sym_entry *s)
{
/* Symbols which vary between passes. Passes 1 and 2 must have
* identical symbol lists. The kallsyms_* symbols below are only added
@@ -214,30 +173,29 @@ symbol_valid(struct sym_entry *s)
}

/* Exclude symbols which vary between passes. */
- if (strstr(s->sym + offset, "_compiled."))
+ if (strstr((char *)s->sym + offset, "_compiled."))
return 0;

for (i = 0; special_symbols[i]; i++)
- if( strcmp(s->sym + offset, special_symbols[i]) == 0 )
+ if( strcmp((char *)s->sym + offset, special_symbols[i]) == 0 )
return 0;

return 1;
}

-static void
-read_map(FILE *in)
+static void read_map(FILE *in)
{
while (!feof(in)) {
- if (cnt >= size) {
- size += 10000;
- table = realloc(table, sizeof(*table) * size);
+ if (table_cnt >= table_size) {
+ table_size += 10000;
+ table = realloc(table, sizeof(*table) * table_size);
if (!table) {
fprintf(stderr, "out of memory\n");
exit (1);
}
}
- if (read_symbol(in, &table[cnt]) == 0)
- cnt++;
+ if (read_symbol(in, &table[table_cnt]) == 0)
+ table_cnt++;
}
}

@@ -281,10 +239,9 @@ static int expand_symbol(unsigned char *
return total;
}

-static void
-write_src(void)
+static void write_src(void)
{
- int i, k, off, valid;
+ unsigned int i, k, off;
unsigned int best_idx[256];
unsigned int *markers;
char buf[KSYM_NAME_LEN+1];
@@ -301,33 +258,24 @@ write_src(void)
printf(".data\n");

output_label("kallsyms_addresses");
- valid = 0;
- for (i = 0; i < cnt; i++) {
- if (table[i].flags & SYM_FLAG_VALID) {
- printf("\tPTR\t%#llx\n", table[i].addr);
- valid++;
- }
+ for (i = 0; i < table_cnt; i++) {
+ printf("\tPTR\t%#llx\n", table[i].addr);
}
printf("\n");

output_label("kallsyms_num_syms");
- printf("\tPTR\t%d\n", valid);
+ printf("\tPTR\t%d\n", table_cnt);
printf("\n");

/* table of offset markers, that give the offset in the compressed stream
* every 256 symbols */
- markers = (unsigned int *) malloc(sizeof(unsigned int)*((valid + 255) / 256));
+ markers = (unsigned int *) malloc(sizeof(unsigned int) * ((table_cnt + 255) / 256));

output_label("kallsyms_names");
- valid = 0;
off = 0;
- for (i = 0; i < cnt; i++) {
-
- if (!table[i].flags & SYM_FLAG_VALID)
- continue;
-
- if ((valid & 0xFF) == 0)
- markers[valid >> 8] = off;
+ for (i = 0; i < table_cnt; i++) {
+ if ((i & 0xFF) == 0)
+ markers[i >> 8] = off;

printf("\t.byte 0x%02x", table[i].len);
for (k = 0; k < table[i].len; k++)
@@ -335,12 +283,11 @@ write_src(void)
printf("\n");

off += table[i].len + 1;
- valid++;
}
printf("\n");

output_label("kallsyms_markers");
- for (i = 0; i < ((valid + 255) >> 8); i++)
+ for (i = 0; i < ((table_cnt + 255) >> 8); i++)
printf("\tPTR\t%d\n", markers[i]);
printf("\n");

@@ -350,7 +297,7 @@ write_src(void)
off = 0;
for (i = 0; i < 256; i++) {
best_idx[i] = off;
- expand_symbol(best_table[i],best_table_len[i],buf);
+ expand_symbol(best_table[i], best_table_len[i], buf);
printf("\t.asciz\t\"%s\"\n", buf);
off += strlen(buf) + 1;
}
@@ -365,153 +312,13 @@ write_src(void)

/* table lookup compression functions */

-static inline unsigned int rehash_token(unsigned int hash, unsigned char data)
-{
- return ((hash * 16777619) ^ data);
-}
-
-static unsigned int hash_token(unsigned char *data, int len)
-{
- unsigned int hash=HASH_BASE_OFFSET;
- int i;
-
- for (i = 0; i < len; i++)
- hash = rehash_token(hash, data[i]);
-
- return HASH_FOLD(hash);
-}
-
-/* find a token given its data and hash value */
-static struct token *find_token_hash(unsigned char *data, int len, unsigned int hash)
-{
- struct token *ptr;
-
- ptr = hash_table[hash];
-
- while (ptr) {
- if ((ptr->len == len) && (memcmp(ptr->data, data, len) == 0))
- return ptr;
- ptr=ptr->next;
- }
-
- return NULL;
-}
-
-static inline void insert_token_in_group(struct token *head, struct token *ptr)
-{
- ptr->right = head->right;
- ptr->right->left = ptr;
- head->right = ptr;
- ptr->left = head;
-}
-
-static inline void remove_token_from_group(struct token *ptr)
-{
- ptr->left->right = ptr->right;
- ptr->right->left = ptr->left;
-}
-
-
-/* build the counts for all the tokens that start with "data", and have lenghts
- * from 2 to "len" */
-static void learn_token(unsigned char *data, int len)
-{
- struct token *ptr,*last_ptr;
- int i, newprofit;
- unsigned int hash = HASH_BASE_OFFSET;
- unsigned int hashes[MAX_TOK_SIZE + 1];
-
- if (len > MAX_TOK_SIZE)
- len = MAX_TOK_SIZE;
-
- /* calculate and store the hash values for all the sub-tokens */
- hash = rehash_token(hash, data[0]);
- for (i = 2; i <= len; i++) {
- hash = rehash_token(hash, data[i-1]);
- hashes[i] = HASH_FOLD(hash);
- }
-
- last_ptr = NULL;
- ptr = NULL;
-
- for (i = len; i >= 2; i--) {
- hash = hashes[i];
-
- if (!ptr) ptr = find_token_hash(data, i, hash);
-
- if (!ptr) {
- /* create a new token entry */
- ptr = (struct token *) malloc(sizeof(*ptr));
-
- memcpy(ptr->data, data, i);
- ptr->len = i;
-
- /* when we create an entry, it's profit is 0 because
- * we also take into account the size of the token on
- * the compressed table. We then subtract GOOD_BAD_THRESHOLD
- * so that the test to see if this token belongs to
- * the good or bad list, is a comparison to zero */
- ptr->profit = -GOOD_BAD_THRESHOLD;
-
- ptr->next = hash_table[hash];
- hash_table[hash] = ptr;
-
- insert_token_in_group(&bad_head, ptr);
-
- ptr->smaller = NULL;
- } else {
- newprofit = ptr->profit + (ptr->len - 1);
- /* check to see if this token needs to be moved to a
- * different list */
- if((ptr->profit < 0) && (newprofit >= 0)) {
- remove_token_from_group(ptr);
- insert_token_in_group(&good_head,ptr);
- }
- ptr->profit = newprofit;
- }
-
- if (last_ptr) last_ptr->smaller = ptr;
- last_ptr = ptr;
-
- ptr = ptr->smaller;
- }
-}
-
-/* decrease the counts for all the tokens that start with "data", and have lenghts
- * from 2 to "len". This function is much simpler than learn_token because we have
- * more guarantees (tho tokens exist, the ->smaller pointer is set, etc.)
- * The two separate functions exist only because of compression performance */
-static void forget_token(unsigned char *data, int len)
-{
- struct token *ptr;
- int i, newprofit;
- unsigned int hash=0;
-
- if (len > MAX_TOK_SIZE) len = MAX_TOK_SIZE;
-
- hash = hash_token(data, len);
- ptr = find_token_hash(data, len, hash);
-
- for (i = len; i >= 2; i--) {
-
- newprofit = ptr->profit - (ptr->len - 1);
- if ((ptr->profit >= 0) && (newprofit < 0)) {
- remove_token_from_group(ptr);
- insert_token_in_group(&bad_head, ptr);
- }
- ptr->profit=newprofit;
-
- ptr=ptr->smaller;
- }
-}
-
/* count all the possible tokens in a symbol */
static void learn_symbol(unsigned char *symbol, int len)
{
int i;

for (i = 0; i < len - 1; i++)
- learn_token(symbol + i, len - i);
+ token_profit[ symbol[i] + (symbol[i + 1] << 8) ]++;
}

/* decrease the count for all the possible tokens in a symbol */
@@ -520,117 +327,90 @@ static void forget_symbol(unsigned char
int i;

for (i = 0; i < len - 1; i++)
- forget_token(symbol + i, len - i);
+ token_profit[ symbol[i] + (symbol[i + 1] << 8) ]--;
}

-/* set all the symbol flags and do the initial token count */
+/* remove all the invalid symbols from the table and do the initial token count */
static void build_initial_tok_table(void)
{
- int i, use_it, valid;
+ unsigned int i, pos;

- valid = 0;
- for (i = 0; i < cnt; i++) {
- table[i].flags = 0;
+ pos = 0;
+ for (i = 0; i < table_cnt; i++) {
if ( symbol_valid(&table[i]) ) {
- table[i].flags |= SYM_FLAG_VALID;
- valid++;
+ if (pos != i)
+ table[pos] = table[i];
+ learn_symbol(table[pos].sym, table[pos].len);
+ pos++;
}
}
-
- use_it = 0;
- for (i = 0; i < cnt; i++) {
-
- /* subsample the available symbols. This method is almost like
- * a Bresenham's algorithm to get uniformly distributed samples
- * across the symbol table */
- if (table[i].flags & SYM_FLAG_VALID) {
-
- use_it += WORKING_SET;
-
- if (use_it >= valid) {
- table[i].flags |= SYM_FLAG_SAMPLED;
- use_it -= valid;
- }
- }
- if (table[i].flags & SYM_FLAG_SAMPLED)
- learn_symbol(table[i].sym, table[i].len);
- }
+ table_cnt = pos;
}

/* replace a given token in all the valid symbols. Use the sampled symbols
* to update the counts */
-static void compress_symbols(unsigned char *str, int tlen, int idx)
+static void compress_symbols(unsigned char *str, int idx)
{
- int i, len, learn, size;
- unsigned char *p;
-
- for (i = 0; i < cnt; i++) {
+ unsigned int i, len, size;
+ unsigned char *p1, *p2;

- if (!(table[i].flags & SYM_FLAG_VALID)) continue;
+ for (i = 0; i < table_cnt; i++) {

len = table[i].len;
- learn = 0;
- p = table[i].sym;
+ p1 = table[i].sym;
+
+ /* find the token on the symbol */
+ p2 = memmem(p1, len, str, 2);
+ if (!p2) continue;
+
+ /* decrease the counts for this symbol's tokens */
+ forget_symbol(table[i].sym, len);
+
+ size = len;

do {
+ *p2 = idx;
+ p2++;
+ size -= (p2 - p1);
+ memmove(p2, p2 + 1, size);
+ p1 = p2;
+ len--;
+
+ if (size < 2) break;
+
/* find the token on the symbol */
- p = (unsigned char *) strstr((char *) p, (char *) str);
- if (!p) break;
+ p2 = memmem(p1, size, str, 2);

- if (!learn) {
- /* if this symbol was used to count, decrease it */
- if (table[i].flags & SYM_FLAG_SAMPLED)
- forget_symbol(table[i].sym, len);
- learn = 1;
- }
+ } while (p2);

- *p = idx;
- size = (len - (p - table[i].sym)) - tlen + 1;
- memmove(p + 1, p + tlen, size);
- p++;
- len -= tlen - 1;
-
- } while (size >= tlen);
-
- if(learn) {
- table[i].len = len;
- /* if this symbol was used to count, learn it again */
- if(table[i].flags & SYM_FLAG_SAMPLED)
- learn_symbol(table[i].sym, len);
- }
+ table[i].len = len;
+
+ /* increase the counts for this symbol's new tokens */
+ learn_symbol(table[i].sym, len);
}
}

/* search the token with the maximum profit */
-static struct token *find_best_token(void)
+static int find_best_token(void)
{
- struct token *ptr,*best,*head;
- int bestprofit;
+ int i, best, bestprofit;

bestprofit=-10000;
+ best = 0;

- /* failsafe: if the "good" list is empty search from the "bad" list */
- if(good_head.right == &good_head) head = &bad_head;
- else head = &good_head;
-
- ptr = head->right;
- best = NULL;
- while (ptr != head) {
- if (ptr->profit > bestprofit) {
- bestprofit = ptr->profit;
- best = ptr;
+ for (i = 0; i < 0x10000; i++) {
+ if (token_profit[i] > bestprofit) {
+ best = i;
+ bestprofit = token_profit[i];
}
- ptr = ptr->right;
}
-
return best;
}

/* this is the core of the algorithm: calculate the "best" table */
static void optimize_result(void)
{
- struct token *best;
- int i;
+ int i, best;

/* using the '\0' symbol last allows compress_symbols to use standard
* fast string functions */
@@ -644,14 +424,12 @@ static void optimize_result(void)
best = find_best_token();

/* place it in the "best" table */
- best_table_len[i] = best->len;
- memcpy(best_table[i], best->data, best_table_len[i]);
- /* zero terminate the token so that we can use strstr
- in compress_symbols */
- best_table[i][best_table_len[i]]='\0';
+ best_table_len[i] = 2;
+ best_table[i][0] = best & 0xFF;
+ best_table[i][1] = (best >> 8) & 0xFF;

/* replace this token in all the valid symbols */
- compress_symbols(best_table[i], best_table_len[i], i);
+ compress_symbols(best_table[i], i);
}
}
}
@@ -659,39 +437,28 @@ static void optimize_result(void)
/* start by placing the symbols that are actually used on the table */
static void insert_real_symbols_in_table(void)
{
- int i, j, c;
+ unsigned int i, j, c;

memset(best_table, 0, sizeof(best_table));
memset(best_table_len, 0, sizeof(best_table_len));

- for (i = 0; i < cnt; i++) {
- if (table[i].flags & SYM_FLAG_VALID) {
- for (j = 0; j < table[i].len; j++) {
- c = table[i].sym[j];
- best_table[c][0]=c;
- best_table_len[c]=1;
- }
+ for (i = 0; i < table_cnt; i++) {
+ for (j = 0; j < table[i].len; j++) {
+ c = table[i].sym[j];
+ best_table[c][0]=c;
+ best_table_len[c]=1;
}
}
}

static void optimize_token_table(void)
{
- memset(hash_table, 0, sizeof(hash_table));
-
- good_head.left = &good_head;
- good_head.right = &good_head;
-
- bad_head.left = &bad_head;
- bad_head.right = &bad_head;
-
build_initial_tok_table();

insert_real_symbols_in_table();

/* When valid symbol is not registered, exit to error */
- if (good_head.left == good_head.right &&
- bad_head.left == bad_head.right) {
+ if (!table_cnt) {
fprintf(stderr, "No valid symbol.\n");
exit(1);
}
@@ -700,8 +467,7 @@ static void optimize_token_table(void)
}

-int
-main(int argc, char **argv)
+int main(int argc, char **argv)
{
if (argc >= 2) {
int i;