Messages in this thread Patch in this message | | | Date | Fri, 18 Jan 2008 11:20:46 -0500 | From | Masami Hiramatsu <> | Subject | [PATCH]Fix the order of atomic operations in restore_previous_kprobes on ia64 |
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From: Masami Hiramatsu <mhiramat@redhat.com>
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@redhat.com> --- 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@redhat.com, masami.hiramatsu.pt@hitachi.com
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