Commit f1389181 authored by Peter Zijlstra's avatar Peter Zijlstra
Browse files

kallsyms: Take callthunks into account 



Since the pre-symbol function padding is an integral part of the
symbol make kallsyms report it as part of the symbol by reporting it
as sym-x instead of prev_sym+y.

Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220915111148.409656012@infradead.org
parent 7825451f

kernel/kallsyms.c

+40 −5
Original line number Diff line number Diff line
@@ -293,6 +293,12 @@ static unsigned long get_symbol_pos(unsigned long addr, 
	return low;

}



#ifdef CONFIG_FUNCTION_PADDING_BYTES

#define PADDING_BYTES	CONFIG_FUNCTION_PADDING_BYTES

#else

#define PADDING_BYTES	0

#endif



/*

 * Lookup an address but don't bother to find any names.

 */
@@ -300,13 +306,25 @@ int kallsyms_lookup_size_offset(unsigned long addr, unsigned long *symbolsize, 
				unsigned long *offset)

{

	char namebuf[KSYM_NAME_LEN];

	int ret;



	addr += PADDING_BYTES;



	if (is_ksym_addr(addr)) {

		get_symbol_pos(addr, symbolsize, offset);

		return 1;

		ret = 1;

		goto found;

	}

	return !!module_address_lookup(addr, symbolsize, offset, NULL, NULL, namebuf) ||

	       !!__bpf_address_lookup(addr, symbolsize, offset, namebuf);



	ret = !!module_address_lookup(addr, symbolsize, offset, NULL, NULL, namebuf);

	if (!ret) {

		ret = !!__bpf_address_lookup(addr, symbolsize,

					     offset, namebuf);

	}

found:

	if (ret && offset)

		*offset -= PADDING_BYTES;

	return ret;

}



static const char *kallsyms_lookup_buildid(unsigned long addr,
@@ -319,6 +337,8 @@ static const char *kallsyms_lookup_buildid(unsigned long addr, 
	namebuf[KSYM_NAME_LEN - 1] = 0;

	namebuf[0] = 0;



	addr += PADDING_BYTES;



	if (is_ksym_addr(addr)) {

		unsigned long pos;
@@ -348,6 +368,8 @@ static const char *kallsyms_lookup_buildid(unsigned long addr, 


found:

	cleanup_symbol_name(namebuf);

	if (ret && offset)

		*offset -= PADDING_BYTES;

	return ret;

}
@@ -374,6 +396,8 @@ int lookup_symbol_name(unsigned long addr, char *symname) 
	symname[0] = '\0';

	symname[KSYM_NAME_LEN - 1] = '\0';



	addr += PADDING_BYTES;



	if (is_ksym_addr(addr)) {

		unsigned long pos;
@@ -401,6 +425,8 @@ int lookup_symbol_attrs(unsigned long addr, unsigned long *size, 
	name[0] = '\0';

	name[KSYM_NAME_LEN - 1] = '\0';



	addr += PADDING_BYTES;



	if (is_ksym_addr(addr)) {

		unsigned long pos;
@@ -417,6 +443,8 @@ int lookup_symbol_attrs(unsigned long addr, unsigned long *size, 
		return res;



found:

	if (offset)

		*offset -= PADDING_BYTES;

	cleanup_symbol_name(name);

	return 0;

}
@@ -442,8 +470,15 @@ static int __sprint_symbol(char *buffer, unsigned long address, 
	len = strlen(buffer);

	offset -= symbol_offset;



	if (add_offset)

		len += sprintf(buffer + len, "+%#lx/%#lx", offset, size);

	if (add_offset) {

		char s = '+';



		if ((long)offset < 0) {

			s = '-';

			offset = 0UL - offset;

		}

		len += sprintf(buffer + len, "%c%#lx/%#lx", s, offset, size);

	}



	if (modname) {

		len += sprintf(buffer + len, " [%s", modname);