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    Subject[PATCH 5.10 167/530] devtmpfs: fix placement of complete() call
    Date
    From: Rasmus Villemoes <linux@rasmusvillemoes.dk>

    [ Upstream commit 38f087de8947700d3b06d3d1594490e0f611c5d1 ]

    Calling complete() from within the __init function is wrong -
    theoretically, the init process could proceed all the way to freeing
    the init mem before the devtmpfsd thread gets to execute the return
    instruction in devtmpfs_setup().

    In practice, it seems to be harmless as gcc inlines devtmpfs_setup()
    into devtmpfsd(). So the calls of the __init functions init_chdir()
    etc. actually happen from devtmpfs_setup(), but the __ref on that one
    silences modpost (it's all right, because those calls happen before
    the complete()). But it does make the __init annotation of the setup
    function moot, which we'll fix in a subsequent patch.

    Fixes: bcbacc4909f1 ("devtmpfs: refactor devtmpfsd()")
    Reviewed-by: Christoph Hellwig <hch@lst.de>
    Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
    Link: https://lore.kernel.org/r/20210312103027.2701413-1-linux@rasmusvillemoes.dk
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    drivers/base/devtmpfs.c | 2 +-
    1 file changed, 1 insertion(+), 1 deletion(-)

    diff --git a/drivers/base/devtmpfs.c b/drivers/base/devtmpfs.c
    index eac184e6d657..a71d14117943 100644
    --- a/drivers/base/devtmpfs.c
    +++ b/drivers/base/devtmpfs.c
    @@ -416,7 +416,6 @@ static int __init devtmpfs_setup(void *p)
    init_chroot(".");
    out:
    *(int *)p = err;
    - complete(&setup_done);
    return err;
    }

    @@ -429,6 +428,7 @@ static int __ref devtmpfsd(void *p)
    {
    int err = devtmpfs_setup(p);

    + complete(&setup_done);
    if (err)
    return err;
    devtmpfs_work_loop();
    --
    2.30.2


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