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

From: Robin Getz
Date: Sun Apr 06 2008 - 00:18:51 EST


On Thu 3 Apr 2008 19:41, Rusty Russell pondered:
> On Thursday 03 April 2008 08:01:25 Robin Getz wrote:
> > 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...
>
> Looks good. I don't have extratext in my kernel tho
> (v2.6.25-rc8-139-ge315c12). Otherwise I'd suspect it should be consistently
> used between extable and kallsyms.

update patch - refactored a bit more - all address checking is removed from
kallsyms, and moved to extable - if this looks ok - I will send it properly...


Index: linux-2.6.x/kernel/kallsyms.c
===================================================================
--- linux-2.6.x/kernel/kallsyms.c (revision 4546)
+++ linux-2.6.x/kernel/kallsyms.c (working copy)
@@ -45,38 +45,20 @@

extern const unsigned long kallsyms_markers[] __attribute__((weak));

-static inline int is_kernel_inittext(unsigned long addr)
+static int is_ksym_addr(unsigned long addr)
{
- if (addr >= (unsigned long)_sinittext
- && addr <= (unsigned long)_einittext)
- return 1;
- return 0;
-}
+ if (all_var) {
+ if (core_kernel_anywhere(addr))
+ return 1;

-static inline int is_kernel_text(unsigned long addr)
-{
- if (addr >= (unsigned long)_stext && addr <= (unsigned long)_etext)
- return 1;
- return in_gate_area_no_task(addr);
-}
+ return in_gate_area_no_task(addr);
+ }

-static inline int is_kernel(unsigned long addr)
-{
- if (addr >= (unsigned long)_stext && addr <= (unsigned long)_end)
+ if (core_kernel_text(addr))
return 1;
+
return in_gate_area_no_task(addr);
-}

-static int is_ksym_addr(unsigned long addr)
-{
- if (all_var)
- return is_kernel(addr);
-
- return is_kernel_text(addr) || is_kernel_inittext(addr);
}

/* expand a compressed symbol data into the resulting uncompressed string,
@@ -206,7 +188,7 @@

/* 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/kernel/extable.c
===================================================================
--- linux-2.6.x/kernel/extable.c (revision 4541)
+++ linux-2.6.x/kernel/extable.c (working copy)
@@ -40,18 +40,43 @@
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;
+}
+
+#ifdef CONFIG_KALLSYMS_ALL
+int core_kernel_anywhere(unsigned long addr)
+{
+ if (addr >= (unsigned long)_stext && addr <= (unsigned long)_end)
+ return 1;
+ return 0;
+}
+#endif
+
+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)
{
if (core_kernel_text(addr))
@@ -65,3 +90,4 @@
return 1;
return module_text_address(addr) != NULL;
}
+
Index: linux-2.6.x/include/linux/kernel.h
===================================================================
--- linux-2.6.x/include/linux/kernel.h (revision 4541)
+++ 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_inittext(unsigned long addr);
+extern int core_kernel_anywhere(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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