• Heiko Carstens's avatar
    s390/vdso: fix initializing and updating of vdso_data · 5b43bd18
    Heiko Carstens authored
    Li Wang reported that clock_gettime(CLOCK_MONOTONIC_RAW, ...) returns
    incorrect values when time is provided via vdso instead of system call:
    
    vdso_ts_nsec = 4484351380985507, vdso_ts.tv_sec = 4484351, vdso_ts.tv_nsec = 380985507
    sys_ts_nsec  = 1446923235377, sys_ts.tv_sec  = 1446, sys_ts.tv_nsec  = 923235377
    
    Within the s390 specific vdso function __arch_get_hw_counter() reads
    tod clock steering values from the arch_data member of the passed in
    vdso_data structure.
    
    Problem is that only for the CS_HRES_COARSE vdso_data arch_data is
    initialized and gets updated. The CS_RAW specific vdso_data does not
    contain any valid tod_clock_steering information, which explains the
    different values.
    
    Fix this by initializing and updating all vdso_datas.
    Reported-by: default avatarLi Wang <liwang@redhat.com>
    Tested-by: default avatarLi Wang <liwang@redhat.com>
    Fixes: 1ba2d6c0 ("s390/vdso: simplify __arch_get_hw_counter()")
    Link: https://lore.kernel.org/linux-s390/YFnxr1ZlMIOIqjfq@osirisSigned-off-by: default avatarHeiko Carstens <hca@linux.ibm.com>
    5b43bd18
time.c 22.7 KB