• Eric Dumazet's avatar
    time: jiffies_delta_to_clock_t() helper to the rescue · a399a805
    Eric Dumazet authored
    Various /proc/net files sometimes report crazy timer values, expressed
    in clock_t units.
    
    This happens when an expired timer delta (expires - jiffies) is passed
    to jiffies_to_clock_t().
    
    This function has an overflow in :
    
    return div_u64((u64)x * TICK_NSEC, NSEC_PER_SEC / USER_HZ);
    
    commit cbbc719f (time: Change jiffies_to_clock_t() argument type
    to unsigned long) only got around the problem.
    
    As we cant output negative values in /proc/net/tcp without breaking
    various tools, I suggest adding a jiffies_delta_to_clock_t() wrapper
    that caps the negative delta to a 0 value.
    Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
    Reported-by: default avatarMaciej Żenczykowski <maze@google.com>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
    Cc: Andrew Morton <akpm@linux-foundation.org>
    Cc: hank <pyu@redhat.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    a399a805
tcp_ipv4.c 67.2 KB