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    Subject[PATCH 4.12 16/65] fuse: initialize the flock flag in fuse_file on allocation
    Date
    4.12-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Mateusz Jurczyk <mjurczyk@google.com>

    commit 68227c03cba84a24faf8a7277d2b1a03c8959c2c upstream.

    Before the patch, the flock flag could remain uninitialized for the
    lifespan of the fuse_file allocation. Unless set to true in
    fuse_file_flock(), it would remain in an indeterminate state until read in
    an if statement in fuse_release_common(). This could consequently lead to
    taking an unexpected branch in the code.

    The bug was discovered by a runtime instrumentation designed to detect use
    of uninitialized memory in the kernel.

    Signed-off-by: Mateusz Jurczyk <mjurczyk@google.com>
    Fixes: 37fb3a30b462 ("fuse: fix flock")
    Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    fs/fuse/file.c | 2 +-
    1 file changed, 1 insertion(+), 1 deletion(-)

    --- a/fs/fuse/file.c
    +++ b/fs/fuse/file.c
    @@ -46,7 +46,7 @@ struct fuse_file *fuse_file_alloc(struct
    {
    struct fuse_file *ff;

    - ff = kmalloc(sizeof(struct fuse_file), GFP_KERNEL);
    + ff = kzalloc(sizeof(struct fuse_file), GFP_KERNEL);
    if (unlikely(!ff))
    return NULL;


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