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 <[email protected]>

---

 scripts/mod/modpost.c | 50 ++++++++++++++++++++++---------------------
 1 file changed, 26 insertions(+), 24 deletions(-)

scripts/mod/modpost.c +26 -25

index 0d998c54564d..b709b2e623d6 100644
@@ -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.
--

2.19.1.568.g152ad8e336-goog