• Anton Blanchard's avatar
    powerpc/pseries: Duplicate dtl entries sometimes sent to userspace · 84b07386
    Anton Blanchard authored
    When reading from the dispatch trace log (dtl) userspace interface, I
    sometimes see duplicate entries. One example:
    
    # hexdump -C dtl.out
    
    00000000  07 04 00 0c 00 00 48 44  00 00 00 00 00 00 00 00
    00000010  00 0c a0 b4 16 83 6d 68  00 00 00 00 00 00 00 00
    00000020  00 00 00 00 10 00 13 50  80 00 00 00 00 00 d0 32
    
    00000030  07 04 00 0c 00 00 48 44  00 00 00 00 00 00 00 00
    00000040  00 0c a0 b4 16 83 6d 68  00 00 00 00 00 00 00 00
    00000050  00 00 00 00 10 00 13 50  80 00 00 00 00 00 d0 32
    
    The problem is in scan_dispatch_log() where we call dtl_consumer()
    but bail out before incrementing the index.
    
    To fix this I moved dtl_consumer() after the timebase comparison.
    Signed-off-by: default avatarAnton Blanchard <anton@samba.org>
    Cc: stable@vger.kernel.org
    Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
    84b07386
time.c 26.6 KB