KSYM_SYMBOL_LEN fixes

Miles Lane tailing /sys files hit a BUG which Pekka Enberg has tracked
to my 966c8c12dc9e77f931e2281ba25d2f0244b06949 sprint_symbol(): use
less stack exposing a bug in slub's list_locations() -
kallsyms_lookup() writes a 0 to namebuf[KSYM_NAME_LEN-1], but that was
beyond the end of page provided.

The 100 slop which list_locations() allows at end of page looks roughly
enough for all the other stuff it might print after the symbol before
it checks again: break out KSYM_SYMBOL_LEN earlier than before.

Latencytop and ftrace and are using KSYM_NAME_LEN buffers where they
need KSYM_SYMBOL_LEN buffers, and vmallocinfo a 2*KSYM_NAME_LEN buffer
where it wants a KSYM_SYMBOL_LEN buffer: fix those before anyone copies
them.

[akpm@linux-foundation.org: ftrace.h needs module.h]
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc Miles Lane <miles.lane@gmail.com>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Acked-by: Steven Rostedt <srostedt@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 1 deletions

diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 703eb53cfa2b..9c5bc6be2b09 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -6,6 +6,7 @@
 #include <linux/ktime.h>
 #include <linux/init.h>
 #include <linux/types.h>
+#include <linux/module.h>
 #include <linux/kallsyms.h>
 
 #ifdef CONFIG_FUNCTION_TRACER
@@ -231,7 +232,7 @@ ftrace_init_module(unsigned long *start, unsigned long *end) { }
 
 struct boot_trace {
 	pid_t			caller;
-	char			func[KSYM_NAME_LEN];
+	char			func[KSYM_SYMBOL_LEN];
 	int			result;
 	unsigned long long	duration;		/* usecs */
 	ktime_t			calltime;