sprint_symbol(): use less stack

sprint_symbol(), itself used when dumping stacks, has been wasting 128
bytes of stack: lookup the symbol directly into the buffer supplied by the
caller, instead of using a locally declared namebuf.

I believe the name != buffer strcpy() is obsolete: the design here dates
from when module symbol lookup pointed into a supposedly const but sadly
volatile table; nowadays it copies, but an uncalled strcpy() looks better
here than the risk of a recursive BUG_ON().

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 12 insertions, 5 deletions

diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c
index 5072cf1685a2..7b8b0f21a5b1 100644
--- a/kernel/kallsyms.c
+++ b/kernel/kallsyms.c
@@ -304,17 +304,24 @@ int sprint_symbol(char *buffer, unsigned long address)
         char *modname;
         const char *name;
         unsigned long offset, size;
-        char namebuf[KSYM_NAME_LEN];
+        int len;
 
-        name = kallsyms_lookup(address, &size, &offset, &modname, namebuf);
+        name = kallsyms_lookup(address, &size, &offset, &modname, buffer);
         if (!name)
                 return sprintf(buffer, "0x%lx", address);
 
+        if (name != buffer)
+                strcpy(buffer, name);
+        len = strlen(buffer);
+        buffer += len;
+
         if (modname)
-                return sprintf(buffer, "%s+%#lx/%#lx [%s]", name, offset,
-                                size, modname);
+                len += sprintf(buffer, "+%#lx/%#lx [%s]",
+                                                offset, size, modname);
         else
-                return sprintf(buffer, "%s+%#lx/%#lx", name, offset, size);
+                len += sprintf(buffer, "+%#lx/%#lx", offset, size);
+
+        return len;
 }
 
 /* Look up a kernel symbol and print it to the kernel messages. */