diff options
author | Bart Van Assche <bvanassche@acm.org> | 2012-08-14 13:18:53 +0000 |
---|---|---|
committer | Roland Dreier <roland@purestorage.com> | 2012-08-15 12:00:48 -0700 |
commit | 220329916c72ee3d54ae7262b215a050f04a18fc (patch) | |
tree | 0d89f6e3cc8f17b070c16665d3df4e883fda9ddc /drivers/infiniband | |
parent | 0d7614f09c1ebdbaa1599a5aba7593f147bf96ee (diff) |
IB/srp: Fix a race condition
Avoid a crash caused by the scmnd->scsi_done(scmnd) call in
srp_process_rsp() being invoked with scsi_done == NULL. This can
happen if a reply is received during or after a command abort.
Reported-by: Joseph Glanville <joseph.glanville@orionvm.com.au>
Reference: http://marc.info/?l=linux-rdma&m=134314367801595
Cc: <stable@vger.kernel.org>
Acked-by: David Dillow <dillowda@ornl.gov>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Roland Dreier <roland@purestorage.com>
Diffstat (limited to 'drivers/infiniband')
-rw-r--r-- | drivers/infiniband/ulp/srp/ib_srp.c | 87 |
1 files changed, 63 insertions, 24 deletions
diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c index bcbf22ee0aa7..1b5b0c730054 100644 --- a/drivers/infiniband/ulp/srp/ib_srp.c +++ b/drivers/infiniband/ulp/srp/ib_srp.c @@ -586,24 +586,62 @@ static void srp_unmap_data(struct scsi_cmnd *scmnd, scmnd->sc_data_direction); } -static void srp_remove_req(struct srp_target_port *target, - struct srp_request *req, s32 req_lim_delta) +/** + * srp_claim_req - Take ownership of the scmnd associated with a request. + * @target: SRP target port. + * @req: SRP request. + * @scmnd: If NULL, take ownership of @req->scmnd. If not NULL, only take + * ownership of @req->scmnd if it equals @scmnd. + * + * Return value: + * Either NULL or a pointer to the SCSI command the caller became owner of. + */ +static struct scsi_cmnd *srp_claim_req(struct srp_target_port *target, + struct srp_request *req, + struct scsi_cmnd *scmnd) +{ + unsigned long flags; + + spin_lock_irqsave(&target->lock, flags); + if (!scmnd) { + scmnd = req->scmnd; + req->scmnd = NULL; + } else if (req->scmnd == scmnd) { + req->scmnd = NULL; + } else { + scmnd = NULL; + } + spin_unlock_irqrestore(&target->lock, flags); + + return scmnd; +} + +/** + * srp_free_req() - Unmap data and add request to the free request list. + */ +static void srp_free_req(struct srp_target_port *target, + struct srp_request *req, struct scsi_cmnd *scmnd, + s32 req_lim_delta) { unsigned long flags; - srp_unmap_data(req->scmnd, target, req); + srp_unmap_data(scmnd, target, req); + spin_lock_irqsave(&target->lock, flags); target->req_lim += req_lim_delta; - req->scmnd = NULL; list_add_tail(&req->list, &target->free_reqs); spin_unlock_irqrestore(&target->lock, flags); } static void srp_reset_req(struct srp_target_port *target, struct srp_request *req) { - req->scmnd->result = DID_RESET << 16; - req->scmnd->scsi_done(req->scmnd); - srp_remove_req(target, req, 0); + struct scsi_cmnd *scmnd = srp_claim_req(target, req, NULL); + + if (scmnd) { + scmnd->result = DID_RESET << 16; + scmnd->scsi_done(scmnd); + srp_free_req(target, req, scmnd, 0); + } } static int srp_reconnect_target(struct srp_target_port *target) @@ -1073,11 +1111,18 @@ static void srp_process_rsp(struct srp_target_port *target, struct srp_rsp *rsp) complete(&target->tsk_mgmt_done); } else { req = &target->req_ring[rsp->tag]; - scmnd = req->scmnd; - if (!scmnd) + scmnd = srp_claim_req(target, req, NULL); + if (!scmnd) { shost_printk(KERN_ERR, target->scsi_host, "Null scmnd for RSP w/tag %016llx\n", (unsigned long long) rsp->tag); + + spin_lock_irqsave(&target->lock, flags); + target->req_lim += be32_to_cpu(rsp->req_lim_delta); + spin_unlock_irqrestore(&target->lock, flags); + + return; + } scmnd->result = rsp->status; if (rsp->flags & SRP_RSP_FLAG_SNSVALID) { @@ -1092,7 +1137,9 @@ static void srp_process_rsp(struct srp_target_port *target, struct srp_rsp *rsp) else if (rsp->flags & (SRP_RSP_FLAG_DIOVER | SRP_RSP_FLAG_DIUNDER)) scsi_set_resid(scmnd, be32_to_cpu(rsp->data_in_res_cnt)); - srp_remove_req(target, req, be32_to_cpu(rsp->req_lim_delta)); + srp_free_req(target, req, scmnd, + be32_to_cpu(rsp->req_lim_delta)); + scmnd->host_scribble = NULL; scmnd->scsi_done(scmnd); } @@ -1631,25 +1678,17 @@ static int srp_abort(struct scsi_cmnd *scmnd) { struct srp_target_port *target = host_to_target(scmnd->device->host); struct srp_request *req = (struct srp_request *) scmnd->host_scribble; - int ret = SUCCESS; shost_printk(KERN_ERR, target->scsi_host, "SRP abort called\n"); - if (!req || target->qp_in_error) + if (!req || target->qp_in_error || !srp_claim_req(target, req, scmnd)) return FAILED; - if (srp_send_tsk_mgmt(target, req->index, scmnd->device->lun, - SRP_TSK_ABORT_TASK)) - return FAILED; - - if (req->scmnd) { - if (!target->tsk_mgmt_status) { - srp_remove_req(target, req, 0); - scmnd->result = DID_ABORT << 16; - } else - ret = FAILED; - } + srp_send_tsk_mgmt(target, req->index, scmnd->device->lun, + SRP_TSK_ABORT_TASK); + srp_free_req(target, req, scmnd, 0); + scmnd->result = DID_ABORT << 16; - return ret; + return SUCCESS; } static int srp_reset_device(struct scsi_cmnd *scmnd) |