modpost: validate symbol names also in find_elf_symbol

If an ARM mapping symbol shares an address with a valid symbol,
find_elf_symbol can currently return the mapping symbol instead, as the
symbol is not validated. This can result in confusing warnings:

  WARNING: vmlinux.o(.text+0x18f4028): Section mismatch in reference
  from the function set_reset_devices() to the variable .init.text:$x.0

This change adds a call to is_valid_name to find_elf_symbol, similarly
to how it's already used in find_elf_symbol2.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

1 files changed, 26 insertions, 24 deletions

diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index 0d998c54564d..b709b2e623d6 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -1204,6 +1204,30 @@ static int secref_whitelist(const struct sectioncheck *mismatch,
         return 1;
 }
 
+static inline int is_arm_mapping_symbol(const char *str)
+{
+        return str[0] == '$' && strchr("axtd", str[1])
+               && (str[2] == '\0' || str[2] == '.');
+}
+
+/*
+ * If there's no name there, ignore it; likewise, ignore it if it's
+ * one of the magic symbols emitted used by current ARM tools.
+ *
+ * Otherwise if find_symbols_between() returns those symbols, they'll
+ * fail the whitelist tests and cause lots of false alarms ... fixable
+ * only by merging __exit and __init sections into __text, bloating
+ * the kernel (which is especially evil on embedded platforms).
+ */
+static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym)
+{
+        const char *name = elf->strtab + sym->st_name;
+
+        if (!name || !strlen(name))
+                return 0;
+        return !is_arm_mapping_symbol(name);
+}
+
 /**
  * Find symbol based on relocation record info.
  * In some cases the symbol supplied is a valid symbol so
@@ -1229,6 +1253,8 @@ static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf64_Sword addr,
                         continue;
                 if (ELF_ST_TYPE(sym->st_info) == STT_SECTION)
                         continue;
+                if (!is_valid_name(elf, sym))
+                        continue;
                 if (sym->st_value == addr)
                         return sym;
                 /* Find a symbol nearby - addr are maybe negative */
@@ -1247,30 +1273,6 @@ static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf64_Sword addr,
                 return NULL;
 }
 
-static inline int is_arm_mapping_symbol(const char *str)
-{
-        return str[0] == '$' && strchr("axtd", str[1])
-               && (str[2] == '\0' || str[2] == '.');
-}
-
-/*
- * If there's no name there, ignore it; likewise, ignore it if it's
- * one of the magic symbols emitted used by current ARM tools.
- *
- * Otherwise if find_symbols_between() returns those symbols, they'll
- * fail the whitelist tests and cause lots of false alarms ... fixable
- * only by merging __exit and __init sections into __text, bloating
- * the kernel (which is especially evil on embedded platforms).
- */
-static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym)
-{
-        const char *name = elf->strtab + sym->st_name;
-
-        if (!name || !strlen(name))
-                return 0;
-        return !is_arm_mapping_symbol(name);
-}
-
 /*
  * Find symbols before or equal addr and after addr - in the section sec.
  * If we find two symbols with equal offset prefer one with a valid name.