From f1389181622a08d6f1c71407a64df36b809d632b Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 15 Sep 2022 13:11:32 +0200 Subject: [PATCH] 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: Peter Zijlstra (Intel) Signed-off-by: Thomas Gleixner Signed-off-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20220915111148.409656012@infradead.org --- kernel/kallsyms.c | 45 ++++++++++++++++++++++++++++++++++++++++----- 1 file changed, 40 insertions(+), 5 deletions(-) diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c index 60c20f301a6b..cc244c02b4cf 100644 --- a/kernel/kallsyms.c +++ b/kernel/kallsyms.c @@ -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; + } + + ret = !!module_address_lookup(addr, symbolsize, offset, NULL, NULL, namebuf); + if (!ret) { + ret = !!__bpf_address_lookup(addr, symbolsize, + offset, namebuf); } - return !!module_address_lookup(addr, symbolsize, offset, NULL, NULL, namebuf) || - !!__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); -- 2.11.0