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authorSantosh Nayak <santoshprasadnayak@gmail.com>2012-02-26 17:35:03 +0400
committerJames Bottomley <JBottomley@Parallels.com>2012-03-01 02:52:59 +0400
commit50ec5babd3b9da274ac3e0d5ca0c4772e3c7bc8d (patch)
tree8f975cfed3e6bd9b1e15dd862bf8f7ad9dd9387d /drivers/scsi/pm8001/pm8001_hwi.c
parentbdaefbf580cd200ae3230b6aacd1f4f2dadb18e3 (diff)
downloadlinux-50ec5babd3b9da274ac3e0d5ca0c4772e3c7bc8d.tar.xz
[SCSI] pm8001: Fix possible racing condition.
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: Santosh Nayak <santoshprasadnayak@gmail.com> Acked-by: Jack Wang <jack_wang@usish.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Diffstat (limited to 'drivers/scsi/pm8001/pm8001_hwi.c')
-rw-r--r--drivers/scsi/pm8001/pm8001_hwi.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/drivers/scsi/pm8001/pm8001_hwi.c b/drivers/scsi/pm8001/pm8001_hwi.c
index 871d1c3fa01b..dc28ae186450 100644
--- a/drivers/scsi/pm8001/pm8001_hwi.c
+++ b/drivers/scsi/pm8001/pm8001_hwi.c
@@ -3869,7 +3869,9 @@ static int process_oq(struct pm8001_hba_info *pm8001_ha)
void *pMsg1 = NULL;
u8 bc = 0;
u32 ret = MPI_IO_STATUS_FAIL;
+ unsigned long flags;
+ spin_lock_irqsave(&pm8001_ha->lock, flags);
circularQ = &pm8001_ha->outbnd_q_tbl[0];
do {
ret = mpi_msg_consume(pm8001_ha, circularQ, &pMsg1, &bc);
@@ -3890,6 +3892,7 @@ static int process_oq(struct pm8001_hba_info *pm8001_ha)
break;
}
} while (1);
+ spin_unlock_irqrestore(&pm8001_ha->lock, flags);
return ret;
}
@@ -4295,12 +4298,9 @@ static u32 pm8001_chip_is_our_interupt(struct pm8001_hba_info *pm8001_ha)
static irqreturn_t
pm8001_chip_isr(struct pm8001_hba_info *pm8001_ha)
{
- unsigned long flags;
- spin_lock_irqsave(&pm8001_ha->lock, flags);
pm8001_chip_interrupt_disable(pm8001_ha);
process_oq(pm8001_ha);
pm8001_chip_interrupt_enable(pm8001_ha);
- spin_unlock_irqrestore(&pm8001_ha->lock, flags);
return IRQ_HANDLED;
}