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    SubjectRe: [RFC PATCH 02/12] On Tue, 23 Sep 2008, David Miller wrote:
    On Sat, Oct 4, 2008 at 4:02 AM, Thomas Gleixner <> wrote:
    > On Sat, 4 Oct 2008, Jiri Kosina wrote:
    >> On Fri, 3 Oct 2008, Jesse Brandeburg wrote:
    >> > Our experience is different. We are also testing with the "protection
    >> > patch" reverted.
    >> > We see that the problem specifically comes and goes when
    >> > removing/adding the use of set_memory_ro/set_memory_rw to the driver.
    >> But if this patch (which is an obvious workaround, compared to the other
    >> patches which fix real bugs, right?) would be catching some malicious
    >> accessess to the mapped EEPROM, there should be stacktraces present in the
    >> kernel log, right?

    yes, but I think it is just changing timing, i don't see any backtraces either.

    > Exactly. The access to a ro region results in a fault. I have nowhere
    > seen that trigger, but I can reproduce the trylock() WARN_ON, which
    > confirms that there is concurrent access to the NVRAM registers. The
    > backtrace pattern is similar to the one you have seen.

    are you still getting WARN_ON *with* all the mutex based fixes already applied?

    with the mutex patches in place (without protection patch) we are
    still reproducing the issue, until we apply the set_memory_ro patch.
    I had no luck on friday setting a hardware breakpoint on memory access
    with kgdb to catch the writer with a breakpoint.

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      Last update: 2008-10-05 03:27    [W:0.020 / U:4.864 seconds]
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