Re: [PATCH for-next 5/5] IB/isert: Fix for lib/dma_debug check_sync warning

[Jason Gunthorpe <jgg@ziepe.ca>]

On Tue, May 15, 2018 at 06:31:39PM -0700, Dennis Dalessandro wrote:
> From: Alex Estrin <alex.estrin@intel.com>
> 
> The following error message occurs on a target host in a debug build
> during session login:
> 
> [ 3524.411874] WARNING: CPU: 5 PID: 12063 at lib/dma-debug.c:1207 check_sync+0x4ec/0x5b0
> [ 3524.421057] infiniband hfi1_0: DMA-API: device driver tries to sync DMA memory it has not allocated [device address=0x0000000000000000] [size=76 bytes]
> ......snip .....
> 
> [ 3524.535846] CPU: 5 PID: 12063 Comm: iscsi_np Kdump: loaded Not tainted 3.10.0-862.el7.x86_64.debug #1
> [ 3524.546764] Hardware name: Dell Inc. PowerEdge R430/03XKDV, BIOS 1.2.6 06/08/2015
> [ 3524.555740] Call Trace:
> [ 3524.559102]  [<ffffffffa5fe915b>] dump_stack+0x19/0x1b
> [ 3524.565477]  [<ffffffffa58a2f58>] __warn+0xd8/0x100
> [ 3524.571557]  [<ffffffffa58a2fdf>] warn_slowpath_fmt+0x5f/0x80
> [ 3524.578610]  [<ffffffffa5bf5b8c>] check_sync+0x4ec/0x5b0
> [ 3524.585177]  [<ffffffffa58efc3f>] ? set_cpus_allowed_ptr+0x5f/0x1c0
> [ 3524.592812]  [<ffffffffa5bf5cd0>] debug_dma_sync_single_for_cpu+0x80/0x90
> [ 3524.601029]  [<ffffffffa586add3>] ? x2apic_send_IPI_mask+0x13/0x20
> [ 3524.608574]  [<ffffffffa585ee1b>] ? native_smp_send_reschedule+0x5b/0x80
> [ 3524.616699]  [<ffffffffa58e9b76>] ? resched_curr+0xf6/0x140
> [ 3524.623567]  [<ffffffffc0879af0>] isert_create_send_desc.isra.26+0xe0/0x110 [ib_isert]
> [ 3524.633060]  [<ffffffffc087af95>] isert_put_login_tx+0x55/0x8b0 [ib_isert]
> [ 3524.641383]  [<ffffffffa58ef114>] ? try_to_wake_up+0x1a4/0x430
> [ 3524.648561]  [<ffffffffc098cfed>] iscsi_target_do_tx_login_io+0xdd/0x230 [iscsi_target_mod]
> [ 3524.658557]  [<ffffffffc098d827>] iscsi_target_do_login+0x1a7/0x600 [iscsi_target_mod]
> [ 3524.668084]  [<ffffffffa59f9bc9>] ? kstrdup+0x49/0x60
> [ 3524.674420]  [<ffffffffc098e976>] iscsi_target_start_negotiation+0x56/0xc0 [iscsi_target_mod]
> [ 3524.684656]  [<ffffffffc098c2ee>] __iscsi_target_login_thread+0x90e/0x1070 [iscsi_target_mod]
> [ 3524.694901]  [<ffffffffc098ca50>] ? __iscsi_target_login_thread+0x1070/0x1070 [iscsi_target_mod]
> [ 3524.705446]  [<ffffffffc098ca50>] ? __iscsi_target_login_thread+0x1070/0x1070 [iscsi_target_mod]
> [ 3524.715976]  [<ffffffffc098ca78>] iscsi_target_login_thread+0x28/0x60 [iscsi_target_mod]
> [ 3524.725739]  [<ffffffffa58d60ff>] kthread+0xef/0x100
> [ 3524.732007]  [<ffffffffa58d6010>] ? insert_kthread_work+0x80/0x80
> [ 3524.739540]  [<ffffffffa5fff1b7>] ret_from_fork_nospec_begin+0x21/0x21
> [ 3524.747558]  [<ffffffffa58d6010>] ? insert_kthread_work+0x80/0x80
> [ 3524.755088] ---[ end trace 23f8bf9238bd1ed8 ]---
> [ 3595.510822] iSCSI/iqn.1994-05.com.redhat:537fa56299: Unsupported SCSI Opcode 0xa3, sending CHECK_CONDITION.
> 
> The code calls dma_sync on login_tx_desc->dma_addr prior to initializing it
> with dma-mapped address.
> login_tx_desc is a part of iser_conn structure and is used only once
> during login negotiation, so the issue is fixed by eliminating
> dma_sync call for this buffer using a special case routine.
> 
> Cc: <stable@vger.kernel.org>
> Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
> Reviewed-by: Don Dutile <ddutile@redhat.com>
> Signed-off-by: Alex Estrin <alex.estrin@intel.com>
> Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
> ---
>  drivers/infiniband/ulp/isert/ib_isert.c |   26 +++++++++++++++++---------
>  1 files changed, 17 insertions(+), 9 deletions(-)

This sounds like -rc material? Why is it for-next?

> diff --git a/drivers/infiniband/ulp/isert/ib_isert.c b/drivers/infiniband/ulp/isert/ib_isert.c
> index fff40b0..6a55b87 100644
> --- a/drivers/infiniband/ulp/isert/ib_isert.c
> +++ b/drivers/infiniband/ulp/isert/ib_isert.c
> @@ -886,15 +886,9 @@
>  }
>  
>  static void
> -isert_create_send_desc(struct isert_conn *isert_conn,
> -		       struct isert_cmd *isert_cmd,
> -		       struct iser_tx_desc *tx_desc)
> +__isert_create_send_desc(struct isert_device *device,
> +			 struct iser_tx_desc *tx_desc)
>  {
> -	struct isert_device *device = isert_conn->device;
> -	struct ib_device *ib_dev = device->ib_device;
> -
> -	ib_dma_sync_single_for_cpu(ib_dev, tx_desc->dma_addr,
> -				   ISER_HEADERS_LEN, DMA_TO_DEVICE);
>  
>  	memset(&tx_desc->iser_header, 0, sizeof(struct iser_ctrl));
>  	tx_desc->iser_header.flags = ISCSI_CTRL;
> @@ -907,6 +901,20 @@
>  	}
>  }
>  
> +static void
> +isert_create_send_desc(struct isert_conn *isert_conn,
> +		       struct isert_cmd *isert_cmd,
> +		       struct iser_tx_desc *tx_desc)
> +{
> +	struct isert_device *device = isert_conn->device;
> +	struct ib_device *ib_dev = device->ib_device;
> +
> +	ib_dma_sync_single_for_cpu(ib_dev, tx_desc->dma_addr,
> +				   ISER_HEADERS_LEN, DMA_TO_DEVICE);
> +
> +	__isert_create_send_desc(device, tx_desc);
> +}
> +
>  static int
>  isert_init_tx_hdrs(struct isert_conn *isert_conn,
>  		   struct iser_tx_desc *tx_desc)
> @@ -994,7 +1002,7 @@
>  	struct iser_tx_desc *tx_desc = &isert_conn->login_tx_desc;
>  	int ret;
>  
> -	isert_create_send_desc(isert_conn, NULL, tx_desc);
> +	__isert_create_send_desc(device, tx_desc);
>  
>  	memcpy(&tx_desc->iscsi_header, &login->rsp[0],
>  	       sizeof(struct iscsi_hdr));
>