On Fri, Jan 26, 2024 at 04:21:23PM +0100, Daniel Vacek wrote:
> Unfortunately the commit `fd8958efe877` introduced another error
> causing the `descs` array to overflow. This reults in further crashes
> easily reproducible by `sendmsg` system call.
>
> [ 1080.836473] general protection fault, probably for non-canonical address 0x400300015528b00a: 0000 [#1] PREEMPT SMP PTI
> [ 1080.869326] RIP: 0010:hfi1_ipoib_build_ib_tx_headers.constprop.0+0xe1/0x2b0 [hfi1]
> --
> [ 1080.974535] Call Trace:
> [ 1080.976990] <TASK>
> [ 1081.021929] hfi1_ipoib_send_dma_common+0x7a/0x2e0 [hfi1]
> [ 1081.027364] hfi1_ipoib_send_dma_list+0x62/0x270 [hfi1]
> [ 1081.032633] hfi1_ipoib_send+0x112/0x300 [hfi1]
> [ 1081.042001] ipoib_start_xmit+0x2a9/0x2d0 [ib_ipoib]
> [ 1081.046978] dev_hard_start_xmit+0xc4/0x210
> --
> [ 1081.148347] __sys_sendmsg+0x59/0xa0
>
> crash> ipoib_txreq 0xffff9cfeba229f00
> struct ipoib_txreq {
> txreq = {
> list = {
> next = 0xffff9cfeba229f00,
> prev = 0xffff9cfeba229f00
> },
> descp = 0xffff9cfeba229f40,
> coalesce_buf = 0x0,
> wait = 0xffff9cfea4e69a48,
> complete = 0xffffffffc0fe0760 <hfi1_ipoib_sdma_complete>,
> packet_len = 0x46d,
> tlen = 0x0,
> num_desc = 0x0,
> desc_limit = 0x6,
> next_descq_idx = 0x45c,
> coalesce_idx = 0x0,
> flags = 0x0,
> descs = {{
> qw = {0x8024000120dffb00, 0x4} # SDMA_DESC0_FIRST_DESC_FLAG (bit 63)
> }, {
> qw = { 0x3800014231b108, 0x4}
> }, {
> qw = { 0x310000e4ee0fcf0, 0x8}
> }, {
> qw = { 0x3000012e9f8000, 0x8}
> }, {
> qw = { 0x59000dfb9d0000, 0x8}
> }, {
> qw = { 0x78000e02e40000, 0x8}
> }}
> },
> sdma_hdr = 0x400300015528b000, <<< invalid pointer in the tx request structure
> sdma_status = 0x0, SDMA_DESC0_LAST_DESC_FLAG (bit 62)
> complete = 0x0,
> priv = 0x0,
> txq = 0xffff9cfea4e69880,
> skb = 0xffff9d099809f400
> }
>
> With this patch the crashes are no longer reproducible and the machine is stable.
>
> Note, the header file changes are just an unrelated clean-up while I was looking
> around trying to find the bug.
>
> Fixes: fd8958efe877 ("IB/hfi1: Fix sdma.h tx->num_descs off-by-one errors")
> Cc: stable@xxxxxxxxxxxxxxx
> Reported-by: Mats Kronberg <kronberg@xxxxxxxxxx>
> Tested-by: Mats Kronberg <kronberg@xxxxxxxxxx>
> Signed-off-by: Daniel Vacek <neelx@xxxxxxxxxx>
> ---
> drivers/infiniband/hw/hfi1/sdma.c | 2 +-
> drivers/infiniband/hw/hfi1/sdma.h | 17 +++++++----------
> 2 files changed, 8 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/infiniband/hw/hfi1/sdma.c b/drivers/infiniband/hw/hfi1/sdma.c
> index 6e5ac2023328a..b67d23b1f2862 100644
> --- a/drivers/infiniband/hw/hfi1/sdma.c
> +++ b/drivers/infiniband/hw/hfi1/sdma.c
> @@ -3158,7 +3158,7 @@ int _pad_sdma_tx_descs(struct hfi1_devdata *dd, struct sdma_txreq *tx)
> {
> int rval = 0;
>
> - if ((unlikely(tx->num_desc + 1 == tx->desc_limit))) {
> + if ((unlikely(tx->num_desc == tx->desc_limit))) {
Maybe, Dennis?
> rval = _extend_sdma_tx_descs(dd, tx);
> if (rval) {
> __sdma_txclean(dd, tx);
> diff --git a/drivers/infiniband/hw/hfi1/sdma.h b/drivers/infiniband/hw/hfi1/sdma.h
> index d77246b48434f..362815a8da267 100644
> --- a/drivers/infiniband/hw/hfi1/sdma.h
> +++ b/drivers/infiniband/hw/hfi1/sdma.h
> @@ -639,13 +639,13 @@ static inline void sdma_txclean(struct hfi1_devdata *dd, struct sdma_txreq *tx)
> static inline void _sdma_close_tx(struct hfi1_devdata *dd,
> struct sdma_txreq *tx)
> {
> - u16 last_desc = tx->num_desc - 1;
> + struct sdma_desc *desc = &tx->descp[tx->num_desc - 1];
>
> - tx->descp[last_desc].qw[0] |= SDMA_DESC0_LAST_DESC_FLAG;
> - tx->descp[last_desc].qw[1] |= dd->default_desc1;
> + desc->qw[0] |= SDMA_DESC0_LAST_DESC_FLAG;
> + desc->qw[1] |= dd->default_desc1;
> if (tx->flags & SDMA_TXREQ_F_URGENT)
> - tx->descp[last_desc].qw[1] |= (SDMA_DESC1_HEAD_TO_HOST_FLAG |
> - SDMA_DESC1_INT_REQ_FLAG);
> + desc->qw[1] |= (SDMA_DESC1_HEAD_TO_HOST_FLAG |
> + SDMA_DESC1_INT_REQ_FLAG);
Unrelated change which doesn't change anything.
> }
>
> static inline int _sdma_txadd_daddr(
> @@ -670,13 +670,10 @@ static inline int _sdma_txadd_daddr(
> tx->tlen -= len;
> /* special cases for last */
> if (!tx->tlen) {
> - if (tx->packet_len & (sizeof(u32) - 1)) {
> + if (tx->packet_len & (sizeof(u32) - 1))
> rval = _pad_sdma_tx_descs(dd, tx);
> - if (rval)
> - return rval;
> - } else {
> + else
> _sdma_close_tx(dd, tx);
> - }
Same as before, unrelated change.
> }
> return rval;
> }
> --
> 2.43.0
>
