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    SubjectRe: io_uring vs in_compat_syscall()
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    On 7/20/20 12:10 AM, Christoph Hellwig wrote:
    > Hi Jens,
    >
    > I just found a (so far theoretical) issue with the io_uring submission
    > offloading to workqueues or threads. We have lots of places using
    > in_compat_syscall() to check if a syscall needs compat treatmenet.
    > While the biggest users is iocttl(), we also have a fair amount of
    > places using in_compat_task() in read and write methods, and these
    > will not do the wrong thing when used with io_uring under certain
    > conditions. I'm not sure how to best fix this, except for making sure
    > in_compat_syscall() returns true one way or another for these cases.

    We can probably propagate this information in the io_kiocb via a flag,
    and have the io-wq worker set TS_COMPAT if that's the case.

    --
    Jens Axboe

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