From: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Fix the order of atomic operations to prevent overwriting prev_kprobe[0].
To pop values from stack, we must decrement stack index right AFTER
reading values.
Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
---
Details of this issue was reported to
http://sources.redhat.com/bugzilla/show_bug.cgi?id=2071
arch/ia64/kernel/kprobes.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
Index: 2.6.24-rc8/arch/ia64/kernel/kprobes.c
===================================================================
--- 2.6.24-rc8.orig/arch/ia64/kernel/kprobes.c 2008-01-17 21:14:01.000000000 -0500
+++ 2.6.24-rc8/arch/ia64/kernel/kprobes.c 2008-01-17 21:14:01.000000000 -0500
@@ -381,9 +381,10 @@
static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb)
{
unsigned int i;
- i = atomic_sub_return(1, &kcb->prev_kprobe_index);
- __get_cpu_var(current_kprobe) = kcb->prev_kprobe[i].kp;
- kcb->kprobe_status = kcb->prev_kprobe[i].status;
+ i = atomic_read(&kcb->prev_kprobe_index);
+ __get_cpu_var(current_kprobe) = kcb->prev_kprobe[i-1].kp;
+ kcb->kprobe_status = kcb->prev_kprobe[i-1].status;
+ atomic_sub(1, &kcb->prev_kprobe_index);
}
static void __kprobes set_current_kprobe(struct kprobe *p,
--
Masami Hiramatsu
Software Engineer
Hitachi Computer Products (America) Inc.
Software Solutions Division
e-mail: mhiramat@xxxxxxxxxx, masami.hiramatsu.pt@xxxxxxxxxxx
-
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