1 // SPDX-License-Identifier: GPL-2.0-only
3 * kallsyms.c: in-kernel printing of symbolic oopses and stack traces.
5 * Rewritten and vastly simplified by Rusty Russell for in-kernel
7 * Copyright 2002 Rusty Russell <rusty@rustcorp.com.au> IBM Corporation
11 * (25/Aug/2004) Paulo Marques <pmarques@grupopie.com>
12 * Changed the compression method from stem compression to "table lookup"
13 * compression (see scripts/kallsyms.c for a more complete description)
15 #include <linux/kallsyms.h>
16 #include <linux/init.h>
17 #include <linux/seq_file.h>
19 #include <linux/kdb.h>
20 #include <linux/err.h>
21 #include <linux/proc_fs.h>
22 #include <linux/sched.h> /* for cond_resched */
23 #include <linux/ctype.h>
24 #include <linux/slab.h>
25 #include <linux/filter.h>
26 #include <linux/ftrace.h>
27 #include <linux/kprobes.h>
28 #include <linux/build_bug.h>
29 #include <linux/compiler.h>
30 #include <linux/module.h>
31 #include <linux/kernel.h>
32 #include <linux/bsearch.h>
33 #include <linux/btf_ids.h>
35 #include "kallsyms_internal.h"
38 * Expand a compressed symbol data into the resulting uncompressed string,
39 * if uncompressed string is too long (>= maxlen), it will be truncated,
40 * given the offset to where the symbol is in the compressed stream.
42 static unsigned int kallsyms_expand_symbol(unsigned int off,
43 char *result, size_t maxlen)
45 int len, skipped_first = 0;
49 /* Get the compressed symbol length from the first symbol byte. */
50 data = &kallsyms_names[off];
55 /* If MSB is 1, it is a "big" symbol, so needs an additional byte. */
56 if ((len & 0x80) != 0) {
57 len = (len & 0x7F) | (*data << 7);
63 * Update the offset to return the offset for the next symbol on
64 * the compressed stream.
69 * For every byte on the compressed symbol data, copy the table
70 * entry for that byte.
73 tptr = &kallsyms_token_table[kallsyms_token_index[*data]];
94 /* Return to offset to the next symbol. */
99 * Get symbol type information. This is encoded as a single char at the
100 * beginning of the symbol name.
102 static char kallsyms_get_symbol_type(unsigned int off)
105 * Get just the first code, look it up in the token table,
106 * and return the first char from this token.
108 return kallsyms_token_table[kallsyms_token_index[kallsyms_names[off + 1]]];
113 * Find the offset on the compressed stream given and index in the
116 static unsigned int get_symbol_offset(unsigned long pos)
122 * Use the closest marker we have. We have markers every 256 positions,
123 * so that should be close enough.
125 name = &kallsyms_names[kallsyms_markers[pos >> 8]];
128 * Sequentially scan all the symbols up to the point we're searching
129 * for. Every symbol is stored in a [<len>][<len> bytes of data] format,
130 * so we just need to add the len to the current pointer for every
131 * symbol we wish to skip.
133 for (i = 0; i < (pos & 0xFF); i++) {
137 * If MSB is 1, it is a "big" symbol, so we need to look into
138 * the next byte (and skip it, too).
140 if ((len & 0x80) != 0)
141 len = ((len & 0x7F) | (name[1] << 7)) + 1;
143 name = name + len + 1;
146 return name - kallsyms_names;
149 static unsigned long kallsyms_sym_address(int idx)
151 if (!IS_ENABLED(CONFIG_KALLSYMS_BASE_RELATIVE))
152 return kallsyms_addresses[idx];
154 /* values are unsigned offsets if --absolute-percpu is not in effect */
155 if (!IS_ENABLED(CONFIG_KALLSYMS_ABSOLUTE_PERCPU))
156 return kallsyms_relative_base + (u32)kallsyms_offsets[idx];
158 /* ...otherwise, positive offsets are absolute values */
159 if (kallsyms_offsets[idx] >= 0)
160 return kallsyms_offsets[idx];
162 /* ...and negative offsets are relative to kallsyms_relative_base - 1 */
163 return kallsyms_relative_base - 1 - kallsyms_offsets[idx];
166 static bool cleanup_symbol_name(char *s)
170 if (!IS_ENABLED(CONFIG_LTO_CLANG))
174 * LLVM appends various suffixes for local functions and variables that
175 * must be promoted to global scope as part of LTO. This can break
176 * hooking of static functions with kprobes. '.' is not a valid
177 * character in an identifier in C. Suffixes only in LLVM LTO observed:
178 * - foo.llvm.[0-9a-f]+
180 res = strstr(s, ".llvm.");
189 static int compare_symbol_name(const char *name, char *namebuf)
193 ret = strcmp(name, namebuf);
197 if (cleanup_symbol_name(namebuf) && !strcmp(name, namebuf))
203 static int kallsyms_lookup_names(const char *name,
209 unsigned int seq, off;
210 char namebuf[KSYM_NAME_LEN];
213 high = kallsyms_num_syms - 1;
215 while (low <= high) {
216 mid = low + (high - low) / 2;
217 seq = kallsyms_seqs_of_names[mid];
218 off = get_symbol_offset(seq);
219 kallsyms_expand_symbol(off, namebuf, ARRAY_SIZE(namebuf));
220 ret = compare_symbol_name(name, namebuf);
234 seq = kallsyms_seqs_of_names[low - 1];
235 off = get_symbol_offset(seq);
236 kallsyms_expand_symbol(off, namebuf, ARRAY_SIZE(namebuf));
237 if (compare_symbol_name(name, namebuf))
245 while (high < kallsyms_num_syms - 1) {
246 seq = kallsyms_seqs_of_names[high + 1];
247 off = get_symbol_offset(seq);
248 kallsyms_expand_symbol(off, namebuf, ARRAY_SIZE(namebuf));
249 if (compare_symbol_name(name, namebuf))
259 /* Lookup the address for this symbol. Returns 0 if not found. */
260 unsigned long kallsyms_lookup_name(const char *name)
265 /* Skip the search for empty string. */
269 ret = kallsyms_lookup_names(name, &i, NULL);
271 return kallsyms_sym_address(kallsyms_seqs_of_names[i]);
273 return module_kallsyms_lookup_name(name);
277 * Iterate over all symbols in vmlinux. For symbols from modules use
278 * module_kallsyms_on_each_symbol instead.
280 int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *,
284 char namebuf[KSYM_NAME_LEN];
289 for (i = 0, off = 0; i < kallsyms_num_syms; i++) {
290 off = kallsyms_expand_symbol(off, namebuf, ARRAY_SIZE(namebuf));
291 ret = fn(data, namebuf, NULL, kallsyms_sym_address(i));
299 static unsigned long get_symbol_pos(unsigned long addr,
300 unsigned long *symbolsize,
301 unsigned long *offset)
303 unsigned long symbol_start = 0, symbol_end = 0;
304 unsigned long i, low, high, mid;
306 /* This kernel should never had been booted. */
307 if (!IS_ENABLED(CONFIG_KALLSYMS_BASE_RELATIVE))
308 BUG_ON(!kallsyms_addresses);
310 BUG_ON(!kallsyms_offsets);
312 /* Do a binary search on the sorted kallsyms_addresses array. */
314 high = kallsyms_num_syms;
316 while (high - low > 1) {
317 mid = low + (high - low) / 2;
318 if (kallsyms_sym_address(mid) <= addr)
325 * Search for the first aliased symbol. Aliased
326 * symbols are symbols with the same address.
328 while (low && kallsyms_sym_address(low-1) == kallsyms_sym_address(low))
331 symbol_start = kallsyms_sym_address(low);
333 /* Search for next non-aliased symbol. */
334 for (i = low + 1; i < kallsyms_num_syms; i++) {
335 if (kallsyms_sym_address(i) > symbol_start) {
336 symbol_end = kallsyms_sym_address(i);
341 /* If we found no next symbol, we use the end of the section. */
343 if (is_kernel_inittext(addr))
344 symbol_end = (unsigned long)_einittext;
345 else if (IS_ENABLED(CONFIG_KALLSYMS_ALL))
346 symbol_end = (unsigned long)_end;
348 symbol_end = (unsigned long)_etext;
352 *symbolsize = symbol_end - symbol_start;
354 *offset = addr - symbol_start;
360 * Lookup an address but don't bother to find any names.
362 int kallsyms_lookup_size_offset(unsigned long addr, unsigned long *symbolsize,
363 unsigned long *offset)
365 char namebuf[KSYM_NAME_LEN];
367 if (is_ksym_addr(addr)) {
368 get_symbol_pos(addr, symbolsize, offset);
371 return !!module_address_lookup(addr, symbolsize, offset, NULL, NULL, namebuf) ||
372 !!__bpf_address_lookup(addr, symbolsize, offset, namebuf);
375 static const char *kallsyms_lookup_buildid(unsigned long addr,
376 unsigned long *symbolsize,
377 unsigned long *offset, char **modname,
378 const unsigned char **modbuildid, char *namebuf)
382 namebuf[KSYM_NAME_LEN - 1] = 0;
385 if (is_ksym_addr(addr)) {
388 pos = get_symbol_pos(addr, symbolsize, offset);
390 kallsyms_expand_symbol(get_symbol_offset(pos),
391 namebuf, KSYM_NAME_LEN);
401 /* See if it's in a module or a BPF JITed image. */
402 ret = module_address_lookup(addr, symbolsize, offset,
403 modname, modbuildid, namebuf);
405 ret = bpf_address_lookup(addr, symbolsize,
406 offset, modname, namebuf);
409 ret = ftrace_mod_address_lookup(addr, symbolsize,
410 offset, modname, namebuf);
413 cleanup_symbol_name(namebuf);
419 * - modname is set to NULL if it's in the kernel.
420 * - We guarantee that the returned name is valid until we reschedule even if.
421 * It resides in a module.
422 * - We also guarantee that modname will be valid until rescheduled.
424 const char *kallsyms_lookup(unsigned long addr,
425 unsigned long *symbolsize,
426 unsigned long *offset,
427 char **modname, char *namebuf)
429 return kallsyms_lookup_buildid(addr, symbolsize, offset, modname,
433 int lookup_symbol_name(unsigned long addr, char *symname)
438 symname[KSYM_NAME_LEN - 1] = '\0';
440 if (is_ksym_addr(addr)) {
443 pos = get_symbol_pos(addr, NULL, NULL);
445 kallsyms_expand_symbol(get_symbol_offset(pos),
446 symname, KSYM_NAME_LEN);
449 /* See if it's in a module. */
450 res = lookup_module_symbol_name(addr, symname);
455 cleanup_symbol_name(symname);
459 int lookup_symbol_attrs(unsigned long addr, unsigned long *size,
460 unsigned long *offset, char *modname, char *name)
465 name[KSYM_NAME_LEN - 1] = '\0';
467 if (is_ksym_addr(addr)) {
470 pos = get_symbol_pos(addr, size, offset);
472 kallsyms_expand_symbol(get_symbol_offset(pos),
473 name, KSYM_NAME_LEN);
477 /* See if it's in a module. */
478 res = lookup_module_symbol_attrs(addr, size, offset, modname, name);
483 cleanup_symbol_name(name);
487 /* Look up a kernel symbol and return it in a text buffer. */
488 static int __sprint_symbol(char *buffer, unsigned long address,
489 int symbol_offset, int add_offset, int add_buildid)
492 const unsigned char *buildid;
494 unsigned long offset, size;
497 address += symbol_offset;
498 name = kallsyms_lookup_buildid(address, &size, &offset, &modname, &buildid,
501 return sprintf(buffer, "0x%lx", address - symbol_offset);
504 strcpy(buffer, name);
505 len = strlen(buffer);
506 offset -= symbol_offset;
509 len += sprintf(buffer + len, "+%#lx/%#lx", offset, size);
512 len += sprintf(buffer + len, " [%s", modname);
513 #if IS_ENABLED(CONFIG_STACKTRACE_BUILD_ID)
514 if (add_buildid && buildid) {
515 /* build ID should match length of sprintf */
516 #if IS_ENABLED(CONFIG_MODULES)
517 static_assert(sizeof(typeof_member(struct module, build_id)) == 20);
519 len += sprintf(buffer + len, " %20phN", buildid);
522 len += sprintf(buffer + len, "]");
529 * sprint_symbol - Look up a kernel symbol and return it in a text buffer
530 * @buffer: buffer to be stored
531 * @address: address to lookup
533 * This function looks up a kernel symbol with @address and stores its name,
534 * offset, size and module name to @buffer if possible. If no symbol was found,
535 * just saves its @address as is.
537 * This function returns the number of bytes stored in @buffer.
539 int sprint_symbol(char *buffer, unsigned long address)
541 return __sprint_symbol(buffer, address, 0, 1, 0);
543 EXPORT_SYMBOL_GPL(sprint_symbol);
546 * sprint_symbol_build_id - Look up a kernel symbol and return it in a text buffer
547 * @buffer: buffer to be stored
548 * @address: address to lookup
550 * This function looks up a kernel symbol with @address and stores its name,
551 * offset, size, module name and module build ID to @buffer if possible. If no
552 * symbol was found, just saves its @address as is.
554 * This function returns the number of bytes stored in @buffer.
556 int sprint_symbol_build_id(char *buffer, unsigned long address)
558 return __sprint_symbol(buffer, address, 0, 1, 1);
560 EXPORT_SYMBOL_GPL(sprint_symbol_build_id);
563 * sprint_symbol_no_offset - Look up a kernel symbol and return it in a text buffer
564 * @buffer: buffer to be stored
565 * @address: address to lookup
567 * This function looks up a kernel symbol with @address and stores its name
568 * and module name to @buffer if possible. If no symbol was found, just saves
569 * its @address as is.
571 * This function returns the number of bytes stored in @buffer.
573 int sprint_symbol_no_offset(char *buffer, unsigned long address)
575 return __sprint_symbol(buffer, address, 0, 0, 0);
577 EXPORT_SYMBOL_GPL(sprint_symbol_no_offset);
580 * sprint_backtrace - Look up a backtrace symbol and return it in a text buffer
581 * @buffer: buffer to be stored
582 * @address: address to lookup
584 * This function is for stack backtrace and does the same thing as
585 * sprint_symbol() but with modified/decreased @address. If there is a
586 * tail-call to the function marked "noreturn", gcc optimized out code after
587 * the call so that the stack-saved return address could point outside of the
588 * caller. This function ensures that kallsyms will find the original caller
589 * by decreasing @address.
591 * This function returns the number of bytes stored in @buffer.
593 int sprint_backtrace(char *buffer, unsigned long address)
595 return __sprint_symbol(buffer, address, -1, 1, 0);
599 * sprint_backtrace_build_id - Look up a backtrace symbol and return it in a text buffer
600 * @buffer: buffer to be stored
601 * @address: address to lookup
603 * This function is for stack backtrace and does the same thing as
604 * sprint_symbol() but with modified/decreased @address. If there is a
605 * tail-call to the function marked "noreturn", gcc optimized out code after
606 * the call so that the stack-saved return address could point outside of the
607 * caller. This function ensures that kallsyms will find the original caller
608 * by decreasing @address. This function also appends the module build ID to
609 * the @buffer if @address is within a kernel module.
611 * This function returns the number of bytes stored in @buffer.
613 int sprint_backtrace_build_id(char *buffer, unsigned long address)
615 return __sprint_symbol(buffer, address, -1, 1, 1);
618 /* To avoid using get_symbol_offset for every symbol, we carry prefix along. */
619 struct kallsym_iter {
623 loff_t pos_ftrace_mod_end;
626 unsigned int nameoff; /* If iterating in core kernel symbols. */
628 char name[KSYM_NAME_LEN];
629 char module_name[MODULE_NAME_LEN];
634 int __weak arch_get_kallsym(unsigned int symnum, unsigned long *value,
635 char *type, char *name)
640 static int get_ksymbol_arch(struct kallsym_iter *iter)
642 int ret = arch_get_kallsym(iter->pos - kallsyms_num_syms,
643 &iter->value, &iter->type,
647 iter->pos_arch_end = iter->pos;
654 static int get_ksymbol_mod(struct kallsym_iter *iter)
656 int ret = module_get_kallsym(iter->pos - iter->pos_arch_end,
657 &iter->value, &iter->type,
658 iter->name, iter->module_name,
661 iter->pos_mod_end = iter->pos;
669 * ftrace_mod_get_kallsym() may also get symbols for pages allocated for ftrace
670 * purposes. In that case "__builtin__ftrace" is used as a module name, even
671 * though "__builtin__ftrace" is not a module.
673 static int get_ksymbol_ftrace_mod(struct kallsym_iter *iter)
675 int ret = ftrace_mod_get_kallsym(iter->pos - iter->pos_mod_end,
676 &iter->value, &iter->type,
677 iter->name, iter->module_name,
680 iter->pos_ftrace_mod_end = iter->pos;
687 static int get_ksymbol_bpf(struct kallsym_iter *iter)
691 strlcpy(iter->module_name, "bpf", MODULE_NAME_LEN);
693 ret = bpf_get_kallsym(iter->pos - iter->pos_ftrace_mod_end,
694 &iter->value, &iter->type,
697 iter->pos_bpf_end = iter->pos;
705 * This uses "__builtin__kprobes" as a module name for symbols for pages
706 * allocated for kprobes' purposes, even though "__builtin__kprobes" is not a
709 static int get_ksymbol_kprobe(struct kallsym_iter *iter)
711 strlcpy(iter->module_name, "__builtin__kprobes", MODULE_NAME_LEN);
713 return kprobe_get_kallsym(iter->pos - iter->pos_bpf_end,
714 &iter->value, &iter->type,
715 iter->name) < 0 ? 0 : 1;
718 /* Returns space to next name. */
719 static unsigned long get_ksymbol_core(struct kallsym_iter *iter)
721 unsigned off = iter->nameoff;
723 iter->module_name[0] = '\0';
724 iter->value = kallsyms_sym_address(iter->pos);
726 iter->type = kallsyms_get_symbol_type(off);
728 off = kallsyms_expand_symbol(off, iter->name, ARRAY_SIZE(iter->name));
730 return off - iter->nameoff;
733 static void reset_iter(struct kallsym_iter *iter, loff_t new_pos)
735 iter->name[0] = '\0';
736 iter->nameoff = get_symbol_offset(new_pos);
739 iter->pos_arch_end = 0;
740 iter->pos_mod_end = 0;
741 iter->pos_ftrace_mod_end = 0;
742 iter->pos_bpf_end = 0;
747 * The end position (last + 1) of each additional kallsyms section is recorded
748 * in iter->pos_..._end as each section is added, and so can be used to
749 * determine which get_ksymbol_...() function to call next.
751 static int update_iter_mod(struct kallsym_iter *iter, loff_t pos)
755 if ((!iter->pos_arch_end || iter->pos_arch_end > pos) &&
756 get_ksymbol_arch(iter))
759 if ((!iter->pos_mod_end || iter->pos_mod_end > pos) &&
760 get_ksymbol_mod(iter))
763 if ((!iter->pos_ftrace_mod_end || iter->pos_ftrace_mod_end > pos) &&
764 get_ksymbol_ftrace_mod(iter))
767 if ((!iter->pos_bpf_end || iter->pos_bpf_end > pos) &&
768 get_ksymbol_bpf(iter))
771 return get_ksymbol_kprobe(iter);
774 /* Returns false if pos at or past end of file. */
775 static int update_iter(struct kallsym_iter *iter, loff_t pos)
777 /* Module symbols can be accessed randomly. */
778 if (pos >= kallsyms_num_syms)
779 return update_iter_mod(iter, pos);
781 /* If we're not on the desired position, reset to new position. */
782 if (pos != iter->pos)
783 reset_iter(iter, pos);
785 iter->nameoff += get_ksymbol_core(iter);
791 static void *s_next(struct seq_file *m, void *p, loff_t *pos)
795 if (!update_iter(m->private, *pos))
800 static void *s_start(struct seq_file *m, loff_t *pos)
802 if (!update_iter(m->private, *pos))
807 static void s_stop(struct seq_file *m, void *p)
811 static int s_show(struct seq_file *m, void *p)
814 struct kallsym_iter *iter = m->private;
816 /* Some debugging symbols have no name. Ignore them. */
820 value = iter->show_value ? (void *)iter->value : NULL;
822 if (iter->module_name[0]) {
826 * Label it "global" if it is exported,
827 * "local" if not exported.
829 type = iter->exported ? toupper(iter->type) :
831 seq_printf(m, "%px %c %s\t[%s]\n", value,
832 type, iter->name, iter->module_name);
834 seq_printf(m, "%px %c %s\n", value,
835 iter->type, iter->name);
839 static const struct seq_operations kallsyms_op = {
846 #ifdef CONFIG_BPF_SYSCALL
848 struct bpf_iter__ksym {
849 __bpf_md_ptr(struct bpf_iter_meta *, meta);
850 __bpf_md_ptr(struct kallsym_iter *, ksym);
853 static int ksym_prog_seq_show(struct seq_file *m, bool in_stop)
855 struct bpf_iter__ksym ctx;
856 struct bpf_iter_meta meta;
857 struct bpf_prog *prog;
860 prog = bpf_iter_get_info(&meta, in_stop);
865 ctx.ksym = m ? m->private : NULL;
866 return bpf_iter_run_prog(prog, &ctx);
869 static int bpf_iter_ksym_seq_show(struct seq_file *m, void *p)
871 return ksym_prog_seq_show(m, false);
874 static void bpf_iter_ksym_seq_stop(struct seq_file *m, void *p)
877 (void) ksym_prog_seq_show(m, true);
882 static const struct seq_operations bpf_iter_ksym_ops = {
885 .stop = bpf_iter_ksym_seq_stop,
886 .show = bpf_iter_ksym_seq_show,
889 static int bpf_iter_ksym_init(void *priv_data, struct bpf_iter_aux_info *aux)
891 struct kallsym_iter *iter = priv_data;
895 /* cache here as in kallsyms_open() case; use current process
896 * credentials to tell BPF iterators if values should be shown.
898 iter->show_value = kallsyms_show_value(current_cred());
903 DEFINE_BPF_ITER_FUNC(ksym, struct bpf_iter_meta *meta, struct kallsym_iter *ksym)
905 static const struct bpf_iter_seq_info ksym_iter_seq_info = {
906 .seq_ops = &bpf_iter_ksym_ops,
907 .init_seq_private = bpf_iter_ksym_init,
908 .fini_seq_private = NULL,
909 .seq_priv_size = sizeof(struct kallsym_iter),
912 static struct bpf_iter_reg ksym_iter_reg_info = {
914 .feature = BPF_ITER_RESCHED,
915 .ctx_arg_info_size = 1,
917 { offsetof(struct bpf_iter__ksym, ksym),
918 PTR_TO_BTF_ID_OR_NULL },
920 .seq_info = &ksym_iter_seq_info,
923 BTF_ID_LIST(btf_ksym_iter_id)
924 BTF_ID(struct, kallsym_iter)
926 static int __init bpf_ksym_iter_register(void)
928 ksym_iter_reg_info.ctx_arg_info[0].btf_id = *btf_ksym_iter_id;
929 return bpf_iter_reg_target(&ksym_iter_reg_info);
932 late_initcall(bpf_ksym_iter_register);
934 #endif /* CONFIG_BPF_SYSCALL */
936 static inline int kallsyms_for_perf(void)
938 #ifdef CONFIG_PERF_EVENTS
939 extern int sysctl_perf_event_paranoid;
940 if (sysctl_perf_event_paranoid <= 1)
947 * We show kallsyms information even to normal users if we've enabled
948 * kernel profiling and are explicitly not paranoid (so kptr_restrict
949 * is clear, and sysctl_perf_event_paranoid isn't set).
951 * Otherwise, require CAP_SYSLOG (assuming kptr_restrict isn't set to
954 bool kallsyms_show_value(const struct cred *cred)
956 switch (kptr_restrict) {
958 if (kallsyms_for_perf())
962 if (security_capable(cred, &init_user_ns, CAP_SYSLOG,
963 CAP_OPT_NOAUDIT) == 0)
971 static int kallsyms_open(struct inode *inode, struct file *file)
974 * We keep iterator in m->private, since normal case is to
975 * s_start from where we left off, so we avoid doing
976 * using get_symbol_offset for every symbol.
978 struct kallsym_iter *iter;
979 iter = __seq_open_private(file, &kallsyms_op, sizeof(*iter));
985 * Instead of checking this on every s_show() call, cache
986 * the result here at open time.
988 iter->show_value = kallsyms_show_value(file->f_cred);
992 #ifdef CONFIG_KGDB_KDB
993 const char *kdb_walk_kallsyms(loff_t *pos)
995 static struct kallsym_iter kdb_walk_kallsyms_iter;
997 memset(&kdb_walk_kallsyms_iter, 0,
998 sizeof(kdb_walk_kallsyms_iter));
999 reset_iter(&kdb_walk_kallsyms_iter, 0);
1002 if (!update_iter(&kdb_walk_kallsyms_iter, *pos))
1005 /* Some debugging symbols have no name. Ignore them. */
1006 if (kdb_walk_kallsyms_iter.name[0])
1007 return kdb_walk_kallsyms_iter.name;
1010 #endif /* CONFIG_KGDB_KDB */
1012 static const struct proc_ops kallsyms_proc_ops = {
1013 .proc_open = kallsyms_open,
1014 .proc_read = seq_read,
1015 .proc_lseek = seq_lseek,
1016 .proc_release = seq_release_private,
1019 static int __init kallsyms_init(void)
1021 proc_create("kallsyms", 0444, NULL, &kallsyms_proc_ops);
1024 device_initcall(kallsyms_init);