Allow DEBUG_RODATA and KPROBES to co-exist

Do not mark the kernel text read only if KPROBES is in the kernel;
kprobes needs to hot-patch the kernel text to insert it's
instrumentation.

In this case, only mark the .rodata segment as read only.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Tested-by: S. P. Prasanna <prasanna@in.ibm.com>
Cc: Andi Kleen <ak@suse.de>
Cc: William Cohen <wcohen@redhat.com>
Cc: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 2 insertions, 2 deletions

diff --git a/arch/i386/Kconfig.debug b/arch/i386/Kconfig.debug
index 6293920cd1be..b31c0802e1cc 100644
--- a/arch/i386/Kconfig.debug
+++ b/arch/i386/Kconfig.debug
@@ -49,7 +49,6 @@ config DEBUG_PAGEALLOC
 config DEBUG_RODATA
         bool "Write protect kernel read-only data structures"
         depends on DEBUG_KERNEL
-        depends on !KPROBES # temporary for 2.6.22
         help
           Mark the kernel read-only data as write-protected in the pagetables,
           in order to catch accidental (and incorrect) writes to such const
diff --git a/arch/i386/mm/init.c b/arch/i386/mm/init.c
index b22ce8d6b1ba..7135946d3663 100644
--- a/arch/i386/mm/init.c
+++ b/arch/i386/mm/init.c
@@ -799,6 +799,7 @@ void mark_rodata_ro(void)
         unsigned long start = PFN_ALIGN(_text);
         unsigned long size = PFN_ALIGN(_etext) - start;
 
+#ifndef CONFIG_KPROBES
 #ifdef CONFIG_HOTPLUG_CPU
         /* It must still be possible to apply SMP alternatives. */
         if (num_possible_cpus() <= 1)
@@ -808,7 +809,7 @@ void mark_rodata_ro(void)
                                  size >> PAGE_SHIFT, PAGE_KERNEL_RX);
                 printk("Write protecting the kernel text: %luk\n", size >> 10);
         }
-
+#endif
         start += size;
         size = (unsigned long)__end_rodata - start;
         change_page_attr(virt_to_page(start),