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    SubjectRe: [PATCH 0/2 v4] Init the hashed pointer from a worker.
    On Tue 2022-09-27 12:49:10, Sebastian Andrzej Siewior wrote:
    > This is a mini series to initialize the random value, needed for the %p
    > format argument, upfront during boot instead on demand. The latter is
    > problematic on PREEMPT_RT if the first user happens to be in an atomic
    > region.
    >
    > v3…v4:
    > - Added a __read_mostly.
    > - Added Jason's Acked-by for 2/2 after talking to him at Plumbers.
    > While we were discussion several ways of tackling this differently
    > and the possible problems/ side effects that this may cause we
    > happen to notice that the current way of doing things is also a
    > problem if the first printk("%p\n") user happens to be in NMI
    > context.
    > Therefore I leave it to the vsprintf/ printk maintainer to decide
    > if this is -stable material or not. I'm not aware of any NMI code
    > path using %p but then it is not officially forbidden.
    > Assuming unknown_nmi_error() contains %p format the string, then
    > the backtrace at the end of the email will be printed.

    JFYI, both patches are committed into printk/linux.git,
    branch for-6.1-hash-pointer-init

    I have just added a note into the 2nd patch about that it also
    prevents deadlock when printk("%p", ptr) is called under the lock
    used by get_random_bytes(), see
    https://git.kernel.org/pub/scm/linux/kernel/git/printk/linux.git/commit/?h=for-6.1-hash-pointer-init&id=6f0ac3b52a9075b7291a72fb338d08491c1f0a64

    I did not modify the code. The system_unbound_wq can and should be
    fixed separately.

    Best Regards,
    Petr

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