Commit 024ca901 authored May 20, 2014 by Bart Van Assche Committed by Roland Dreier May 20, 2014

IB/srp: Fix a sporadic crash triggered by cable pulling



Avoid that the loops that iterate over the request ring can encounter
a pointer to a SCSI command in req->scmnd that is no longer associated
with that request. If the function srp_unmap_data() is invoked twice
for a SCSI command that is not in flight then that would cause
ib_fmr_pool_unmap() to be invoked with an invalid pointer as argument,
resulting in a kernel oops.

Reported-by: Sagi Grimberg <sagig@mellanox.com>
Reference: http://thread.gmane.org/gmane.linux.drivers.rdma/19068/focus=19069


Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Sagi Grimberg <sagig@mellanox.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Roland Dreier <roland@purestorage.com>

parent d6d211db

drivers/infiniband/ulp/srp/ib_srp.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -1594,6 +1594,12 @@ static int srp_queuecommand(struct Scsi_Host shost, struct scsi_cmnd scmnd)
		err_iu:
		srp_put_tx_iu(target, iu, SRP_IU_CMD);

		/*
		* Avoid that the loops that iterate over the request ring can
		* encounter a dangling SCSI command pointer.
		*/
		req->scmnd = NULL;

		spin_lock_irqsave(&target->lock, flags);
		list_add(&req->list, &target->free_reqs);