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    Subject[PATCH v3 03/15] NTB: Fix UB/bug in ntb_mw_get_align()
    Date
    Simple (1 << pidx) operation causes undefined behaviour when
    pidx >= 32. It must be casted to u64 to match the actual return
    value of ntb_link_is_up() method, so to have all the possible
    peer indexes covered and to get rid of undefined behaviour.
    Additionally there are special macros in "linux/bitops.h" to perform
    the bit-set-shift operations, so it's recommended to have them used
    for proper bit setting.

    Signed-off-by: Serge Semin <fancer.lancer@gmail.com>
    ---
    include/linux/ntb.h | 2 +-
    1 file changed, 1 insertion(+), 1 deletion(-)

    diff --git a/include/linux/ntb.h b/include/linux/ntb.h
    index c1646f2c6344..488e586fb76c 100644
    --- a/include/linux/ntb.h
    +++ b/include/linux/ntb.h
    @@ -764,7 +764,7 @@ static inline int ntb_mw_get_align(struct ntb_dev *ntb, int pidx, int widx,
    resource_size_t *size_align,
    resource_size_t *size_max)
    {
    - if (!(ntb_link_is_up(ntb, NULL, NULL) & (1 << pidx)))
    + if (!(ntb_link_is_up(ntb, NULL, NULL) & BIT_ULL(pidx)))
    return -ENOTCONN;

    return ntb->ops->mw_get_align(ntb, pidx, widx, addr_align, size_align,
    --
    2.12.0
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