[PATCH 4.18 41/53] RDMA/bnxt_re: Fix system crash during RDMA resource initialization

From: Greg Kroah-Hartman
Date: Thu Oct 18 2018 - 13:58:41 EST

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4.18-stable review patch. If anyone has any objections, please let me know.

------------------

From: Selvin Xavier <selvin.xavier@xxxxxxxxxxxx>

[ Upstream commit de5c95d0f518537f59ee5aef762abc46f868c377 ]

bnxt_re_ib_reg acquires and releases the rtnl lock whenever it accesses
the L2 driver.

The following sequence can trigger a crash

Acquires the rtnl_lock ->
Registers roce driver callback with L2 driver ->
release the rtnl lock
bnxt_re acquires the rtnl_lock ->
Request for MSIx vectors ->
release the rtnl_lock

Issue happens when bnxt_re proceeds with remaining part of initialization
and L2 driver invokes bnxt_ulp_irq_stop as a part of bnxt_open_nic.

The crash is in bnxt_qplib_nq_stop_irq as the NQ structures are
not initialized yet,

<snip>
[ 3551.726647] BUG: unable to handle kernel NULL pointer dereference at (null)
[ 3551.726656] IP: [<ffffffffc0840ee9>] bnxt_qplib_nq_stop_irq+0x59/0xb0 [bnxt_re]
[ 3551.726674] PGD 0
[ 3551.726679] Oops: 0002 1 SMP
...
[ 3551.726822] Hardware name: Dell Inc. PowerEdge R720/08RW36, BIOS 2.4.3 07/09/2014
[ 3551.726826] task: ffff97e30eec5ee0 ti: ffff97e3173bc000 task.ti: ffff97e3173bc000
[ 3551.726829] RIP: 0010:[<ffffffffc0840ee9>] [<ffffffffc0840ee9>]
bnxt_qplib_nq_stop_irq+0x59/0xb0 [bnxt_re]
...
[ 3551.726872] Call Trace:
[ 3551.726886] [<ffffffffc082cb9e>] bnxt_re_stop_irq+0x4e/0x70 [bnxt_re]
[ 3551.726899] [<ffffffffc07d6a53>] bnxt_ulp_irq_stop+0x43/0x70 [bnxt_en]
[ 3551.726908] [<ffffffffc07c82f4>] bnxt_reserve_rings+0x174/0x1e0 [bnxt_en]
[ 3551.726917] [<ffffffffc07cafd8>] __bnxt_open_nic+0x368/0x9a0 [bnxt_en]
[ 3551.726925] [<ffffffffc07cb62b>] bnxt_open_nic+0x1b/0x50 [bnxt_en]
[ 3551.726934] [<ffffffffc07cc62f>] bnxt_setup_mq_tc+0x11f/0x260 [bnxt_en]
[ 3551.726943] [<ffffffffc07d5f58>] bnxt_dcbnl_ieee_setets+0xb8/0x1f0 [bnxt_en]
[ 3551.726954] [<ffffffff890f983a>] dcbnl_ieee_set+0x9a/0x250
[ 3551.726966] [<ffffffff88fd6d21>] ? __alloc_skb+0xa1/0x2d0
[ 3551.726972] [<ffffffff890f72fa>] dcb_doit+0x13a/0x210
[ 3551.726981] [<ffffffff89003ff7>] rtnetlink_rcv_msg+0xa7/0x260
[ 3551.726989] [<ffffffff88ffdb00>] ? rtnl_unicast+0x20/0x30
[ 3551.726996] [<ffffffff88bf9dc8>] ? __kmalloc_node_track_caller+0x58/0x290
[ 3551.727002] [<ffffffff890f7326>] ? dcb_doit+0x166/0x210
[ 3551.727007] [<ffffffff88fd6d0d>] ? __alloc_skb+0x8d/0x2d0
[ 3551.727012] [<ffffffff89003f50>] ? rtnl_newlink+0x880/0x880
...
[ 3551.727104] [<ffffffff8911f7d5>] system_call_fastpath+0x1c/0x21
...
[ 3551.727164] RIP [<ffffffffc0840ee9>] bnxt_qplib_nq_stop_irq+0x59/0xb0 [bnxt_re]
[ 3551.727175] RSP <ffff97e3173bf788>
[ 3551.727177] CR2: 0000000000000000

Avoid this inconsistent state and system crash by acquiring
the rtnl lock for the entire duration of device initialization.
Re-factor the code to remove the rtnl lock from the individual function
and acquire and release it from the caller.

Fixes: 1ac5a4047975 ("RDMA/bnxt_re: Add bnxt_re RoCE driver")
Fixes: 6e04b1035689 ("RDMA/bnxt_re: Fix broken RoCE driver due to recent L2 driver changes")
Signed-off-by: Selvin Xavier <selvin.xavier@xxxxxxxxxxxx>
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/infiniband/hw/bnxt_re/main.c | 93 ++++++++++++++---------------------
1 file changed, 38 insertions(+), 55 deletions(-)

--- a/drivers/infiniband/hw/bnxt_re/main.c
+++ b/drivers/infiniband/hw/bnxt_re/main.c
@@ -78,7 +78,7 @@ static struct list_head bnxt_re_dev_list
/* Mutex to protect the list of bnxt_re devices added */
static DEFINE_MUTEX(bnxt_re_dev_lock);
static struct workqueue_struct *bnxt_re_wq;
-static void bnxt_re_ib_unreg(struct bnxt_re_dev *rdev, bool lock_wait);
+static void bnxt_re_ib_unreg(struct bnxt_re_dev *rdev);

/* SR-IOV helper functions */

@@ -182,7 +182,7 @@ static void bnxt_re_shutdown(void *p)
if (!rdev)
return;

- bnxt_re_ib_unreg(rdev, false);
+ bnxt_re_ib_unreg(rdev);
}

static void bnxt_re_stop_irq(void *handle)
@@ -251,7 +251,7 @@ static struct bnxt_ulp_ops bnxt_re_ulp_o
/* Driver registration routines used to let the networking driver (bnxt_en)
* to know that the RoCE driver is now installed
*/
-static int bnxt_re_unregister_netdev(struct bnxt_re_dev *rdev, bool lock_wait)
+static int bnxt_re_unregister_netdev(struct bnxt_re_dev *rdev)
{
struct bnxt_en_dev *en_dev;
int rc;
@@ -260,14 +260,9 @@ static int bnxt_re_unregister_netdev(str
return -EINVAL;

en_dev = rdev->en_dev;
- /* Acquire rtnl lock if it is not invokded from netdev event */
- if (lock_wait)
- rtnl_lock();

rc = en_dev->en_ops->bnxt_unregister_device(rdev->en_dev,
BNXT_ROCE_ULP);
- if (lock_wait)
- rtnl_unlock();
return rc;
}

@@ -281,14 +276,12 @@ static int bnxt_re_register_netdev(struc

en_dev = rdev->en_dev;

- rtnl_lock();
rc = en_dev->en_ops->bnxt_register_device(en_dev, BNXT_ROCE_ULP,
&bnxt_re_ulp_ops, rdev);
- rtnl_unlock();
return rc;
}

-static int bnxt_re_free_msix(struct bnxt_re_dev *rdev, bool lock_wait)
+static int bnxt_re_free_msix(struct bnxt_re_dev *rdev)
{
struct bnxt_en_dev *en_dev;
int rc;
@@ -298,13 +291,9 @@ static int bnxt_re_free_msix(struct bnxt

en_dev = rdev->en_dev;

- if (lock_wait)
- rtnl_lock();

rc = en_dev->en_ops->bnxt_free_msix(rdev->en_dev, BNXT_ROCE_ULP);

- if (lock_wait)
- rtnl_unlock();
return rc;
}

@@ -320,7 +309,6 @@ static int bnxt_re_request_msix(struct b

num_msix_want = min_t(u32, BNXT_RE_MAX_MSIX, num_online_cpus());

- rtnl_lock();
num_msix_got = en_dev->en_ops->bnxt_request_msix(en_dev, BNXT_ROCE_ULP,
rdev->msix_entries,
num_msix_want);
@@ -335,7 +323,6 @@ static int bnxt_re_request_msix(struct b
}
rdev->num_msix = num_msix_got;
done:
- rtnl_unlock();
return rc;
}

@@ -358,24 +345,18 @@ static void bnxt_re_fill_fw_msg(struct b
fw_msg->timeout = timeout;
}

-static int bnxt_re_net_ring_free(struct bnxt_re_dev *rdev, u16 fw_ring_id,
- bool lock_wait)
+static int bnxt_re_net_ring_free(struct bnxt_re_dev *rdev, u16 fw_ring_id)
{
struct bnxt_en_dev *en_dev = rdev->en_dev;
struct hwrm_ring_free_input req = {0};
struct hwrm_ring_free_output resp;
struct bnxt_fw_msg fw_msg;
- bool do_unlock = false;
int rc = -EINVAL;

if (!en_dev)
return rc;

memset(&fw_msg, 0, sizeof(fw_msg));
- if (lock_wait) {
- rtnl_lock();
- do_unlock = true;
- }

bnxt_re_init_hwrm_hdr(rdev, (void *)&req, HWRM_RING_FREE, -1, -1);
req.ring_type = RING_ALLOC_REQ_RING_TYPE_L2_CMPL;
@@ -386,8 +367,6 @@ static int bnxt_re_net_ring_free(struct
if (rc)
dev_err(rdev_to_dev(rdev),
"Failed to free HW ring:%d :%#x", req.ring_id, rc);
- if (do_unlock)
- rtnl_unlock();
return rc;
}

@@ -405,7 +384,6 @@ static int bnxt_re_net_ring_alloc(struct
return rc;

memset(&fw_msg, 0, sizeof(fw_msg));
- rtnl_lock();
bnxt_re_init_hwrm_hdr(rdev, (void *)&req, HWRM_RING_ALLOC, -1, -1);
req.enables = 0;
req.page_tbl_addr = cpu_to_le64(dma_arr[0]);
@@ -426,27 +404,21 @@ static int bnxt_re_net_ring_alloc(struct
if (!rc)
*fw_ring_id = le16_to_cpu(resp.ring_id);

- rtnl_unlock();
return rc;
}

static int bnxt_re_net_stats_ctx_free(struct bnxt_re_dev *rdev,
- u32 fw_stats_ctx_id, bool lock_wait)
+ u32 fw_stats_ctx_id)
{
struct bnxt_en_dev *en_dev = rdev->en_dev;
struct hwrm_stat_ctx_free_input req = {0};
struct bnxt_fw_msg fw_msg;
- bool do_unlock = false;
int rc = -EINVAL;

if (!en_dev)
return rc;

memset(&fw_msg, 0, sizeof(fw_msg));
- if (lock_wait) {
- rtnl_lock();
- do_unlock = true;
- }

bnxt_re_init_hwrm_hdr(rdev, (void *)&req, HWRM_STAT_CTX_FREE, -1, -1);
req.stat_ctx_id = cpu_to_le32(fw_stats_ctx_id);
@@ -457,8 +429,6 @@ static int bnxt_re_net_stats_ctx_free(st
dev_err(rdev_to_dev(rdev),
"Failed to free HW stats context %#x", rc);

- if (do_unlock)
- rtnl_unlock();
return rc;
}

@@ -478,7 +448,6 @@ static int bnxt_re_net_stats_ctx_alloc(s
return rc;

memset(&fw_msg, 0, sizeof(fw_msg));
- rtnl_lock();

bnxt_re_init_hwrm_hdr(rdev, (void *)&req, HWRM_STAT_CTX_ALLOC, -1, -1);
req.update_period_ms = cpu_to_le32(1000);
@@ -490,7 +459,6 @@ static int bnxt_re_net_stats_ctx_alloc(s
if (!rc)
*fw_stats_ctx_id = le32_to_cpu(resp.stat_ctx_id);

- rtnl_unlock();
return rc;
}

@@ -929,19 +897,19 @@ fail:
return rc;
}

-static void bnxt_re_free_nq_res(struct bnxt_re_dev *rdev, bool lock_wait)
+static void bnxt_re_free_nq_res(struct bnxt_re_dev *rdev)
{
int i;

for (i = 0; i < rdev->num_msix - 1; i++) {
- bnxt_re_net_ring_free(rdev, rdev->nq[i].ring_id, lock_wait);
+ bnxt_re_net_ring_free(rdev, rdev->nq[i].ring_id);
bnxt_qplib_free_nq(&rdev->nq[i]);
}
}

-static void bnxt_re_free_res(struct bnxt_re_dev *rdev, bool lock_wait)
+static void bnxt_re_free_res(struct bnxt_re_dev *rdev)
{
- bnxt_re_free_nq_res(rdev, lock_wait);
+ bnxt_re_free_nq_res(rdev);

if (rdev->qplib_res.dpi_tbl.max) {
bnxt_qplib_dealloc_dpi(&rdev->qplib_res,
@@ -1219,7 +1187,7 @@ static int bnxt_re_setup_qos(struct bnxt
return 0;
}

-static void bnxt_re_ib_unreg(struct bnxt_re_dev *rdev, bool lock_wait)
+static void bnxt_re_ib_unreg(struct bnxt_re_dev *rdev)
{
int i, rc;

@@ -1234,28 +1202,27 @@ static void bnxt_re_ib_unreg(struct bnxt
cancel_delayed_work(&rdev->worker);

bnxt_re_cleanup_res(rdev);
- bnxt_re_free_res(rdev, lock_wait);
+ bnxt_re_free_res(rdev);

if (test_and_clear_bit(BNXT_RE_FLAG_RCFW_CHANNEL_EN, &rdev->flags)) {
rc = bnxt_qplib_deinit_rcfw(&rdev->rcfw);
if (rc)
dev_warn(rdev_to_dev(rdev),
"Failed to deinitialize RCFW: %#x", rc);
- bnxt_re_net_stats_ctx_free(rdev, rdev->qplib_ctx.stats.fw_id,
- lock_wait);
+ bnxt_re_net_stats_ctx_free(rdev, rdev->qplib_ctx.stats.fw_id);
bnxt_qplib_free_ctx(rdev->en_dev->pdev, &rdev->qplib_ctx);
bnxt_qplib_disable_rcfw_channel(&rdev->rcfw);
- bnxt_re_net_ring_free(rdev, rdev->rcfw.creq_ring_id, lock_wait);
+ bnxt_re_net_ring_free(rdev, rdev->rcfw.creq_ring_id);
bnxt_qplib_free_rcfw_channel(&rdev->rcfw);
}
if (test_and_clear_bit(BNXT_RE_FLAG_GOT_MSIX, &rdev->flags)) {
- rc = bnxt_re_free_msix(rdev, lock_wait);
+ rc = bnxt_re_free_msix(rdev);
if (rc)
dev_warn(rdev_to_dev(rdev),
"Failed to free MSI-X vectors: %#x", rc);
}
if (test_and_clear_bit(BNXT_RE_FLAG_NETDEV_REGISTERED, &rdev->flags)) {
- rc = bnxt_re_unregister_netdev(rdev, lock_wait);
+ rc = bnxt_re_unregister_netdev(rdev);
if (rc)
dev_warn(rdev_to_dev(rdev),
"Failed to unregister with netdev: %#x", rc);
@@ -1276,6 +1243,12 @@ static int bnxt_re_ib_reg(struct bnxt_re
{
int i, j, rc;

+ bool locked;
+
+ /* Acquire rtnl lock through out this function */
+ rtnl_lock();
+ locked = true;
+
/* Registered a new RoCE device instance to netdev */
rc = bnxt_re_register_netdev(rdev);
if (rc) {
@@ -1374,12 +1347,16 @@ static int bnxt_re_ib_reg(struct bnxt_re
schedule_delayed_work(&rdev->worker, msecs_to_jiffies(30000));
}

+ rtnl_unlock();
+ locked = false;
+
/* Register ib dev */
rc = bnxt_re_register_ib(rdev);
if (rc) {
pr_err("Failed to register with IB: %#x\n", rc);
goto fail;
}
+ set_bit(BNXT_RE_FLAG_IBDEV_REGISTERED, &rdev->flags);
dev_info(rdev_to_dev(rdev), "Device registered successfully");
for (i = 0; i < ARRAY_SIZE(bnxt_re_attributes); i++) {
rc = device_create_file(&rdev->ibdev.dev,
@@ -1395,7 +1372,6 @@ static int bnxt_re_ib_reg(struct bnxt_re
goto fail;
}
}
- set_bit(BNXT_RE_FLAG_IBDEV_REGISTERED, &rdev->flags);
ib_get_eth_speed(&rdev->ibdev, 1, &rdev->active_speed,
&rdev->active_width);
set_bit(BNXT_RE_FLAG_ISSUE_ROCE_STATS, &rdev->flags);
@@ -1404,17 +1380,21 @@ static int bnxt_re_ib_reg(struct bnxt_re

return 0;
free_sctx:
- bnxt_re_net_stats_ctx_free(rdev, rdev->qplib_ctx.stats.fw_id, true);
+ bnxt_re_net_stats_ctx_free(rdev, rdev->qplib_ctx.stats.fw_id);
free_ctx:
bnxt_qplib_free_ctx(rdev->en_dev->pdev, &rdev->qplib_ctx);
disable_rcfw:
bnxt_qplib_disable_rcfw_channel(&rdev->rcfw);
free_ring:
- bnxt_re_net_ring_free(rdev, rdev->rcfw.creq_ring_id, true);
+ bnxt_re_net_ring_free(rdev, rdev->rcfw.creq_ring_id);
free_rcfw:
bnxt_qplib_free_rcfw_channel(&rdev->rcfw);
fail:
- bnxt_re_ib_unreg(rdev, true);
+ if (!locked)
+ rtnl_lock();
+ bnxt_re_ib_unreg(rdev);
+ rtnl_unlock();
+
return rc;
}

@@ -1567,7 +1547,7 @@ static int bnxt_re_netdev_event(struct n
*/
if (atomic_read(&rdev->sched_count) > 0)
goto exit;
- bnxt_re_ib_unreg(rdev, false);
+ bnxt_re_ib_unreg(rdev);
bnxt_re_remove_one(rdev);
bnxt_re_dev_unreg(rdev);
break;
@@ -1646,7 +1626,10 @@ static void __exit bnxt_re_mod_exit(void
*/
flush_workqueue(bnxt_re_wq);
bnxt_re_dev_stop(rdev);
- bnxt_re_ib_unreg(rdev, true);
+ /* Acquire the rtnl_lock as the L2 resources are freed here */
+ rtnl_lock();
+ bnxt_re_ib_unreg(rdev);
+ rtnl_unlock();
bnxt_re_remove_one(rdev);
bnxt_re_dev_unreg(rdev);
}

Next message: Greg Kroah-Hartman: "[PATCH 4.18 50/53] Revert "vfs: fix freeze protection in mnt_want_write_file() for overlayfs""
Previous message: Greg Kroah-Hartman: "[PATCH 4.18 00/53] 4.18.16-stable review"
In reply to: Greg Kroah-Hartman: "[PATCH 4.18 09/53] batman-adv: Prevent duplicated gateway_node entry"
Next in thread: Greg Kroah-Hartman: "[PATCH 4.18 50/53] Revert "vfs: fix freeze protection in mnt_want_write_file() for overlayfs""
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