linux-kernel - Re: PATCH [1/1]: Don't return symbol lables in init sections after they have been freed

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Message-Id: <200804021801.25937.rgetz@blackfin.uclinux.org>
Date:	Wed, 2 Apr 2008 18:01:25 -0400
From:	Robin Getz <rgetz@...ckfin.uclinux.org>
To:	"Rusty Russell" <rusty@...tcorp.com.au>
Cc:	"Andrew Morton" <akpm@...ux-foundation.org>,
	"LKML" <linux-kernel@...r.kernel.org>
Subject: Re: PATCH [1/1]: Don't return symbol lables in init sections after they have been freed

On Tue 4 Mar 2008 20:43, Rusty Russell pondered:
>     As to the actual patch, your kallsyms.c patch matches 
> a2da4052f1df6bc77749f84496fe731ab8b458f7's change to extable.c: please 
> resubmit with just that one.  For bonus points, look at combining the extable 
> and kallsyms logic so we don't diverge in future...

OK since this took so long, I went for bonus points...

The only think I wasn't sure about - is since it now does things in extable.c,
it removes the static inline functions from kallsyms.c - which could cause a
potential slowdown...

I'm sure this will not apply to the mm tree, (it was based on 2.6.24.3), but
should provide some idea for feedback.

Index: linux-2.6.x/kernel/extable.c
===================================================================
--- linux-2.6.x/kernel/extable.c	(revision 4461)
+++ linux-2.6.x/kernel/extable.c	(working copy)
@@ -40,17 +40,40 @@
 	return e;
 }
 
-int core_kernel_text(unsigned long addr)
+int core_kernel_inittext(unsigned long addr)
 {
+	if (addr >= (unsigned long)_sinittext &&
+	    addr <= (unsigned long)_einittext)
+		return 1;
+	return 0;
+}
+
+int core_kernel_extratext(unsigned long addr)
+{
+	if (addr >= (unsigned long)_sextratext &&
+	    addr <= (unsigned long)_eextratext)
+		return 1;
+	return 0;
+}
+
+int __core_kernel_text(unsigned long addr)
+{
 	if (addr >= (unsigned long)_stext &&
 	    addr <= (unsigned long)_etext)
 		return 1;
 
-	if (addr >= (unsigned long)_sinittext &&
-	    addr <= (unsigned long)_einittext)
 		return 1;
 	return 0;
+
 }
+int core_kernel_text(unsigned long addr)
+{
+	return __core_kernel_text(addr) || core_kernel_inittext(addr);
+}
 
 int __kernel_text_address(unsigned long addr)
 {
@@ -65,3 +88,4 @@
 		return 1;
 	return module_text_address(addr) != NULL;
 }
+
Index: linux-2.6.x/kernel/kallsyms.c
===================================================================
--- linux-2.6.x/kernel/kallsyms.c	(revision 4461)
+++ linux-2.6.x/kernel/kallsyms.c	(working copy)
@@ -45,47 +45,24 @@
 
 extern const unsigned long kallsyms_markers[] __attribute__((weak));
 
-static inline int is_kernel_inittext(unsigned long addr)
-{
-	if (addr >= (unsigned long)_sinittext
-	    && addr <= (unsigned long)_einittext)
-		return 1;
-	return 0;
-}
-
-static inline int is_kernel_extratext(unsigned long addr)
-{
-	if (addr >= (unsigned long)_sextratext
-	    && addr <= (unsigned long)_eextratext)
-		return 1;
-	return 0;
-}
-
 static inline int is_kernel_text(unsigned long addr)
 {
-	if (addr >= (unsigned long)_stext && addr <= (unsigned long)_etext)
+	if (core_kernel_text(addr))
 		return 1;
-	return in_gate_area_no_task(addr);
-}
 
-static inline int is_kernel(unsigned long addr)
-{
-	if (addr >= (unsigned long)_stext && addr <= (unsigned long)_end)
-		return 1;
 	return in_gate_area_no_task(addr);
 }
 
 static int is_ksym_addr(unsigned long addr)
 {
-	if (all_var)
-		return is_kernel(addr);
+	if (all_var) {
+		if (addr >= (unsigned long)_stext && addr <= (unsigned long)_end)
+			return 1;
+		else
+			return in_gate_area_no_task(addr);
+	}
 
-	return is_kernel_text(addr) || is_kernel_inittext(addr) ||
-		is_kernel_extratext(addr);
+	return is_kernel_text(addr) || core_kernel_extratext(addr);
 }
 
 /* expand a compressed symbol data into the resulting uncompressed string,
@@ -215,7 +192,7 @@
 
 	/* if we found no next symbol, we use the end of the section */
 	if (!symbol_end) {
-		if (is_kernel_inittext(addr))
+		if (core_kernel_inittext(addr))
 			symbol_end = (unsigned long)_einittext;
 		else if (all_var)
 			symbol_end = (unsigned long)_end;
Index: linux-2.6.x/include/linux/kernel.h
===================================================================
--- linux-2.6.x/include/linux/kernel.h	(revision 4461)
+++ linux-2.6.x/include/linux/kernel.h	(working copy)
@@ -167,6 +167,8 @@
 extern unsigned long long memparse(char *ptr, char **retptr);
 
 extern int core_kernel_text(unsigned long addr);
+extern int core_kernel_extratext(unsigned long addr);
+extern int core_kernel_inittext(unsigned long addr);
 extern int __kernel_text_address(unsigned long addr);
 extern int kernel_text_address(unsigned long addr);
 struct pid;

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