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    SubjectRe: [PATCH] robust futex thread exit race

    * Martin Schwidefsky <> wrote:

    > Hi Ingo,
    > I finally found the bug that causes tst-robust8 from the glibc to fail
    > on s390x. Turned out to be a common code problem with the processing of
    > the robust futex list. The patch below fixes the bug for me.

    good catch! A quick preliminary review of your patch indicates it's fine
    - and it might be v2.6.23 material.

    Acked-by: Ingo Molnar <>

    > Calling handle_futex_death in exit_robust_list for the different
    > robust mutexes of a thread basically frees the mutex. Another thread
    > might grab the lock immediately which updates the next pointer of the
    > mutex. fetch_robust_entry over the next pointer might therefore branch
    > into the robust mutex list of a different thread. This can cause two
    > problems: 1) some mutexes held by the dead thread are not getting
    > freed and 2) some mutexs held by a different thread are freed. The
    > next point need to be read before calling handle_futex_death.

    nasty race... Ulrich, Thomas, do you concur?

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      Last update: 2007-09-30 17:23    [W:0.021 / U:26.020 seconds]
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