From 41df7b02db82cf6c14f094757bac3830d10a827f Mon Sep 17 00:00:00 2001 From: Hiral Shah Date: Mon, 10 Nov 2014 12:54:36 -0800 Subject: Fnic: Fnic Driver crashed with NULL pointer reference When issuing I/O request, if the I/O completes before returning from fnic_queuecommand(), we may be referencing scsi_cmnd structure that may be freed by interrupt handler. Acquring IO lock would synchronize fnic_queuecommand and interrupt handler. - Increment fnic version from 1.6.0.15 to 1.6.0.16 Signed-off-by: Hiral Shah Signed-off-by: Sesidhar Baddela Signed-off-by: Anil Chintalapati Signed-off-by: Christoph Hellwig --- drivers/scsi/fnic/fnic_scsi.c | 21 ++++++++++++++++++--- 1 file changed, 18 insertions(+), 3 deletions(-) (limited to 'drivers/scsi/fnic/fnic_scsi.c') diff --git a/drivers/scsi/fnic/fnic_scsi.c b/drivers/scsi/fnic/fnic_scsi.c index 29d23a3c0686..2097de42a147 100644 --- a/drivers/scsi/fnic/fnic_scsi.c +++ b/drivers/scsi/fnic/fnic_scsi.c @@ -421,9 +421,10 @@ static int fnic_queuecommand_lck(struct scsi_cmnd *sc, void (*done)(struct scsi_ int ret; u64 cmd_trace; int sg_count = 0; - unsigned long flags; + unsigned long flags = 0; unsigned long ptr; struct fc_rport_priv *rdata; + spinlock_t *io_lock = NULL; if (unlikely(fnic_chk_state_flags_locked(fnic, FNIC_FLAGS_IO_BLOCKED))) return SCSI_MLQUEUE_HOST_BUSY; @@ -509,6 +510,13 @@ static int fnic_queuecommand_lck(struct scsi_cmnd *sc, void (*done)(struct scsi_ } } + /* + * Will acquire lock defore setting to IO initialized. + */ + + io_lock = fnic_io_lock_hash(fnic, sc); + spin_lock_irqsave(io_lock, flags); + /* initialize rest of io_req */ io_req->port_id = rport->port_id; io_req->start_time = jiffies; @@ -525,11 +533,9 @@ static int fnic_queuecommand_lck(struct scsi_cmnd *sc, void (*done)(struct scsi_ * In case another thread cancelled the request, * refetch the pointer under the lock. */ - spinlock_t *io_lock = fnic_io_lock_hash(fnic, sc); FNIC_TRACE(fnic_queuecommand, sc->device->host->host_no, sc->request->tag, sc, 0, 0, 0, (((u64)CMD_FLAGS(sc) << 32) | CMD_STATE(sc))); - spin_lock_irqsave(io_lock, flags); io_req = (struct fnic_io_req *)CMD_SP(sc); CMD_SP(sc) = NULL; CMD_STATE(sc) = FNIC_IOREQ_CMD_COMPLETE; @@ -538,6 +544,10 @@ static int fnic_queuecommand_lck(struct scsi_cmnd *sc, void (*done)(struct scsi_ fnic_release_ioreq_buf(fnic, io_req, sc); mempool_free(io_req, fnic->io_req_pool); } + atomic_dec(&fnic->in_flight); + /* acquire host lock before returning to SCSI */ + spin_lock(lp->host->host_lock); + return ret; } else { atomic64_inc(&fnic_stats->io_stats.active_ios); atomic64_inc(&fnic_stats->io_stats.num_ios); @@ -559,6 +569,11 @@ out: sc->request->tag, sc, io_req, sg_count, cmd_trace, (((u64)CMD_FLAGS(sc) >> 32) | CMD_STATE(sc))); + + /* if only we issued IO, will we have the io lock */ + if (CMD_FLAGS(sc) & FNIC_IO_INITIALIZED) + spin_unlock_irqrestore(io_lock, flags); + atomic_dec(&fnic->in_flight); /* acquire host lock before returning to SCSI */ spin_lock(lp->host->host_lock); -- cgit v1.2.3