Messages in this thread | | | Date | Tue, 11 Mar 2008 14:17:14 -0400 | From | Masami Hiramatsu <> | Subject | Re: [PATCH -mm] kprobes: kprobe-booster for ia64 |
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Hi Shaohua,
Shaohua Li wrote: > Hi, > On Tue, 2008-03-11 at 02:25 +0800, Masami Hiramatsu wrote: >> Shaohua Li wrote: >>> On Sat, 2008-03-08 at 00:01 +0800, Masami Hiramatsu wrote: >>> There is no lock to protect the flag. If one cpu invokes other_kp >> and >>> the other cpu is changing the flag, what's the result? >> I think that other cpu never change the flag, because the caller of >> this >> function(__register_kprobe) locks kprobe_mutex in kernel/kprobes.c. > I mean if one cpu is doing register_kprobe, which will change other_kp's > flag. Another cpu is running into other_kp's break point, which will > look at the flag, there is a window (between the second cpu looks at the > flag and doing boost) the first cpu can change the flag in the window. > It appears we will lose one probe, but not sure if this is over > thinking.
Sure, it is possible to lose just one probe in that time, but in next time, we do not lose it. So, I think it is not a problem.
Thanks,
-- Masami Hiramatsu
Software Engineer Hitachi Computer Products (America) Inc. Software Solutions Division
e-mail: mhiramat@redhat.com
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