From d436de8ce25f53a8a880a931886821f632247943 Mon Sep 17 00:00:00 2001 From: Martin Peschke Date: Tue, 4 Sep 2012 15:23:36 +0200 Subject: [PATCH] [SCSI] zfcp: only access zfcp_scsi_dev for valid scsi_device __scsi_remove_device (e.g. due to dev_loss_tmo) calls zfcp_scsi_slave_destroy which in turn sends a close LUN FSF request to the adapter. After 30 seconds without response, zfcp_erp_timeout_handler kicks the ERP thread failing the close LUN ERP action. zfcp_erp_wait in zfcp_erp_lun_shutdown_wait and thus zfcp_scsi_slave_destroy returns and then scsi_device is no longer valid. Sometime later the response to the close LUN FSF request may finally come in. However, commit b62a8d9b45b971a67a0f8413338c230e3117dff5 "[SCSI] zfcp: Use SCSI device data zfcp_scsi_dev instead of zfcp_unit" introduced a number of attempts to unconditionally access struct zfcp_scsi_dev through struct scsi_device causing a use-after-free. This leads to an Oops due to kernel page fault in one of: zfcp_fsf_abort_fcp_command_handler, zfcp_fsf_open_lun_handler, zfcp_fsf_close_lun_handler, zfcp_fsf_req_trace, zfcp_fsf_fcp_handler_common. Move dereferencing of zfcp private data zfcp_scsi_dev allocated in scsi_device via scsi_transport_reserve_device after the check for potentially aborted FSF request and thus no longer valid scsi_device. Only then assign sdev_to_zfcp(sdev) to the local auto variable struct zfcp_scsi_dev *zfcp_sdev. Signed-off-by: Martin Peschke Signed-off-by: Steffen Maier Cc: #2.6.37+ Signed-off-by: James Bottomley --- drivers/s390/scsi/zfcp_fsf.c | 19 ++++++++++++++----- 1 file changed, 14 insertions(+), 5 deletions(-) diff --git a/drivers/s390/scsi/zfcp_fsf.c b/drivers/s390/scsi/zfcp_fsf.c index 9ffdc335429c..c96320d79fbc 100644 --- a/drivers/s390/scsi/zfcp_fsf.c +++ b/drivers/s390/scsi/zfcp_fsf.c @@ -801,12 +801,14 @@ int zfcp_fsf_status_read(struct zfcp_qdio *qdio) static void zfcp_fsf_abort_fcp_command_handler(struct zfcp_fsf_req *req) { struct scsi_device *sdev = req->data; - struct zfcp_scsi_dev *zfcp_sdev = sdev_to_zfcp(sdev); + struct zfcp_scsi_dev *zfcp_sdev; union fsf_status_qual *fsq = &req->qtcb->header.fsf_status_qual; if (req->status & ZFCP_STATUS_FSFREQ_ERROR) return; + zfcp_sdev = sdev_to_zfcp(sdev); + switch (req->qtcb->header.fsf_status) { case FSF_PORT_HANDLE_NOT_VALID: if (fsq->word[0] == fsq->word[1]) { @@ -1769,13 +1771,15 @@ static void zfcp_fsf_open_lun_handler(struct zfcp_fsf_req *req) { struct zfcp_adapter *adapter = req->adapter; struct scsi_device *sdev = req->data; - struct zfcp_scsi_dev *zfcp_sdev = sdev_to_zfcp(sdev); + struct zfcp_scsi_dev *zfcp_sdev; struct fsf_qtcb_header *header = &req->qtcb->header; struct fsf_qtcb_bottom_support *bottom = &req->qtcb->bottom.support; if (req->status & ZFCP_STATUS_FSFREQ_ERROR) return; + zfcp_sdev = sdev_to_zfcp(sdev); + atomic_clear_mask(ZFCP_STATUS_COMMON_ACCESS_DENIED | ZFCP_STATUS_COMMON_ACCESS_BOXED | ZFCP_STATUS_LUN_SHARED | @@ -1886,11 +1890,13 @@ int zfcp_fsf_open_lun(struct zfcp_erp_action *erp_action) static void zfcp_fsf_close_lun_handler(struct zfcp_fsf_req *req) { struct scsi_device *sdev = req->data; - struct zfcp_scsi_dev *zfcp_sdev = sdev_to_zfcp(sdev); + struct zfcp_scsi_dev *zfcp_sdev; if (req->status & ZFCP_STATUS_FSFREQ_ERROR) return; + zfcp_sdev = sdev_to_zfcp(sdev); + switch (req->qtcb->header.fsf_status) { case FSF_PORT_HANDLE_NOT_VALID: zfcp_erp_adapter_reopen(zfcp_sdev->port->adapter, 0, "fscuh_1"); @@ -1980,7 +1986,7 @@ static void zfcp_fsf_req_trace(struct zfcp_fsf_req *req, struct scsi_cmnd *scsi) { struct fsf_qual_latency_info *lat_in; struct latency_cont *lat = NULL; - struct zfcp_scsi_dev *zfcp_sdev = sdev_to_zfcp(scsi->device); + struct zfcp_scsi_dev *zfcp_sdev; struct zfcp_blk_drv_data blktrc; int ticks = req->adapter->timer_ticks; @@ -1995,6 +2001,7 @@ static void zfcp_fsf_req_trace(struct zfcp_fsf_req *req, struct scsi_cmnd *scsi) if (req->adapter->adapter_features & FSF_FEATURE_MEASUREMENT_DATA && !(req->status & ZFCP_STATUS_FSFREQ_ERROR)) { + zfcp_sdev = sdev_to_zfcp(scsi->device); blktrc.flags |= ZFCP_BLK_LAT_VALID; blktrc.channel_lat = lat_in->channel_lat * ticks; blktrc.fabric_lat = lat_in->fabric_lat * ticks; @@ -2032,12 +2039,14 @@ static void zfcp_fsf_fcp_handler_common(struct zfcp_fsf_req *req) { struct scsi_cmnd *scmnd = req->data; struct scsi_device *sdev = scmnd->device; - struct zfcp_scsi_dev *zfcp_sdev = sdev_to_zfcp(sdev); + struct zfcp_scsi_dev *zfcp_sdev; struct fsf_qtcb_header *header = &req->qtcb->header; if (unlikely(req->status & ZFCP_STATUS_FSFREQ_ERROR)) return; + zfcp_sdev = sdev_to_zfcp(sdev); + switch (header->fsf_status) { case FSF_HANDLE_MISMATCH: case FSF_PORT_HANDLE_NOT_VALID: