• Santosh Nayak's avatar
    [SCSI] pm8001: Fix possible racing condition. · 50ec5bab
    Santosh Nayak authored
    There is a possble racing scenario.
    
    'process_oq' is called by two routines, as shown below.
    
    pm8001_8001_dispatch = {
             .......
    
            .isr             = pm8001_chip_isr --> process_oq,// A
            .isr_process_oq  = process_oq,                   //  B
            .....
    }
    
    process_oq() --> process_one_iomb() --> mpi_sata_completion()
    
    In 'mpi_sata_completion', "pm8001_ha->lock" is first released.
    It means lock is taken before,  which is true for
    the context A, as 'pm8001_ha->lock' is taken in 'pm8001_chip_isr()'
    
    But for context B there is no lock taken before and pm8001_ha->lock
    is unlocked in 'mpi_sata_completion()'. This may unlock the lock
    taken in context A. Possible racing ??
    
    If 'pm8001_ha->lock' is taken in 'process_oq()' instead of
    'pm8001_chip_isr' then the above issue can be avoided.
    Signed-off-by: default avatarSantosh Nayak <santoshprasadnayak@gmail.com>
    Acked-by: default avatarJack Wang <jack_wang@usish.com>
    Signed-off-by: default avatarJames Bottomley <JBottomley@Parallels.com>
    50ec5bab
pm8001_hwi.c 150 KB