linux-kernel - [PATCH][bugfix?][kprobes][vunmap?]: use vm_map_ram() in text

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Date:	Tue, 27 Jan 2009 21:39:28 -0500
From:	Masami Hiramatsu <mhiramat@...hat.com>
To:	Nick Piggin <npiggin@...e.de>,
	Mathieu Desnoyers <mathieu.desnoyers@...ymtl.ca>
CC:	LKML <linux-kernel@...r.kernel.org>,
	Ananth N Mavinakayanahalli <ananth@...ibm.com>,
	Jim Keniston <jkenisto@...ibm.com>,
	systemtap-ml <systemtap@...rces.redhat.com>,
	"Frank Ch. Eigler" <fche@...hat.com>
Subject: [PATCH][bugfix?][kprobes][vunmap?]: use vm_map_ram() in text_poke()

Use vm_map_ram() instead of vmap() in text_poke(), because text_poke()
just want to map pages temporarily.

---
As far as I tested, this patch works fine for me.
However, there might be another hidden bug in the kernel...
We need to fix that too.

 arch/x86/kernel/alternative.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Index: 2.6-rc/arch/x86/kernel/alternative.c
===================================================================
--- 2.6-rc.orig/arch/x86/kernel/alternative.c
+++ 2.6-rc/arch/x86/kernel/alternative.c
@@ -515,12 +515,12 @@ void *__kprobes text_poke(void *addr, co
 	BUG_ON(!pages[0]);
 	if (!pages[1])
 		nr_pages = 1;
-	vaddr = vmap(pages, nr_pages, VM_MAP, PAGE_KERNEL);
+	vaddr = vm_map_ram(pages, nr_pages, -1, PAGE_KERNEL);
 	BUG_ON(!vaddr);
 	local_irq_save(flags);
 	memcpy(&vaddr[(unsigned long)addr & ~PAGE_MASK], opcode, len);
 	local_irq_restore(flags);
-	vunmap(vaddr);
+	vm_unmap_ram(vaddr, nr_pages);
 	sync_core();
 	/* Could also do a CLFLUSH here to speed up CPU recovery; but
 	   that causes hangs on some VIA CPUs. */
-- 
Masami Hiramatsu

Software Engineer
Hitachi Computer Products (America) Inc.
Software Solutions Division

e-mail: mhiramat@...hat.com

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