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    SubjectRe: [RFC PATCH net 1/2] [BUGFIX] bonding: use local function pointer of bond->recv_probe in bond_handle_frame
    Hi WANG Cong

    Thank you for your comments.

    (2011/10/07 22:24), Américo Wang wrote:
    > On Fri, Oct 7, 2011 at 8:49 PM, Mitsuo Hayasaka
    > <> wrote:
    >> The bond->recv_probe is called in bond_handle_frame() when
    >> a packet is received, but bond_close() sets it to NULL. So,
    >> a panic occurs when both functions work in parallel.
    >> Why this happen:
    >> After null pointer check of bond->recv_probe, an sk_buff is
    >> duplicated and bond->recv_probe is called in bond_handle_frame.
    >> So, a panic occurs when bond_close() is called between the
    >> check and call of bond->recv_probe.
    >> Patch:
    >> This patch uses a local function pointer of bond->recv_probe
    >> in bond_handle_frame(). So, it can avoid the null pointer
    >> dereference.
    > Hmm, I don't doubt it can fix the problem, I am wondering if
    > bond->recv_probe should be protected by bond->lock...

    Indeed, in general any resources should be protected from the asynchronous

    At first, I thought it should be handled with lock protection, as well.
    However, I guess that using bond->lock on this kind of hot-path may
    introduces unnecessary overhead. In addition, this code works well
    without the strict lock protection. So, I think this change is the
    right way to fix it.

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      Last update: 2011-10-11 15:05    [W:0.026 / U:27.892 seconds]
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