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RDMA/bnxt_re: Avoid CPU lockups due fifo occupancy check loop

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BugLink: https://bugs.launchpad.net/bugs/2109640

commit 8be3e5b0c96beeefe9d5486b96575d104d3e7d17 upstream.

Driver waits indefinitely for the fifo occupancy to go below a threshold
as soon as the pacing interrupt is received. This can cause soft lockup on
one of the processors, if the rate of DB is very high.

Add a loop count for FPGA and exit the __wait_for_fifo_occupancy_below_th
if the loop is taking more time. Pacing will be continuing until the
occupancy is below the threshold. This is ensured by the checks in
bnxt_re_pacing_timer_exp and further scheduling the work for pacing based
on the fifo occupancy.

Fixes: 2ad4e6303a ("RDMA/bnxt_re: Implement doorbell pacing algorithm")
Link: https://patch.msgid.link/r/1728373302-19530-7-git-send-email-selvin.xavier@broadcom.com
Reviewed-by: Kalesh AP <kalesh-anakkur.purayil@broadcom.com>
Reviewed-by: Chandramohan Akula <chandramohan.akula@broadcom.com>
Signed-off-by: Selvin Xavier <selvin.xavier@broadcom.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
[ Add the declaration of variable pacing_data to make it work on 6.6.y ]
Signed-off-by: Alva Lan <alvalan9@foxmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CVE-2024-50157
Signed-off-by: Manuel Diewald <manuel.diewald@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
This commit is contained in:
Selvin Xavier
2024-10-08 00:41:38 -07:00
committed by Stefan Bader
parent daac0055a0
commit a84f266655
1 changed files with 10 additions and 0 deletions
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drivers/infiniband/hw/bnxt_re/main.c
+10
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@@ -485,6 +485,8 @@ static void bnxt_re_set_default_pacing_data(struct bnxt_re_dev *rdev)
static void __wait_for_fifo_occupancy_below_th(struct bnxt_re_dev *rdev)
{
u32 read_val, fifo_occup;
struct bnxt_qplib_db_pacing_data *pacing_data = rdev->qplib_res.pacing_data;
u32 retry_fifo_check = 1000;
/* loop shouldn't run infintely as the occupancy usually goes
* below pacing algo threshold as soon as pacing kicks in.
@@ -500,6 +502,14 @@ static void __wait_for_fifo_occupancy_below_th(struct bnxt_re_dev *rdev)
if (fifo_occup < rdev->qplib_res.pacing_data->pacing_th)
break;
if (!retry_fifo_check--) {
dev_info_once(rdev_to_dev(rdev),
"%s: fifo_occup = 0x%xfifo_max_depth = 0x%x pacing_th = 0x%x\n",
__func__, fifo_occup, pacing_data->fifo_max_depth,
pacing_data->pacing_th);
break;
}
}
}