[PATCH AUTOSEL 5.4 5/9] qed: fix possible unpaired spin_{un}lock_bh in _qed_mcp_cmd_and_union()

Sasha Levin
2021-07-27T13:28:47Z

From: Jia He <justin.he@arm.com>

[ Upstream commit 6206b7981a36476f4695d661ae139f7db36a802d ]

Liajian reported a bug_on hit on a ThunderX2 arm64 server with FastLinQ
QL41000 ethernet controller:
BUG: scheduling while atomic: kworker/0:4/531/0x00000200
[qed_probe:488()]hw prepare failed
kernel BUG at mm/vmalloc.c:2355!
Internal error: Oops - BUG: 0 [#1] SMP
CPU: 0 PID: 531 Comm: kworker/0:4 Tainted: G W 5.4.0-77-generic #86-Ubuntu
pstate: 00400009 (nzcv daif +PAN -UAO)
Call trace:
vunmap+0x4c/0x50
iounmap+0x48/0x58
qed_free_pci+0x60/0x80 [qed]
qed_probe+0x35c/0x688 [qed]
__qede_probe+0x88/0x5c8 [qede]
qede_probe+0x60/0xe0 [qede]
local_pci_probe+0x48/0xa0
work_for_cpu_fn+0x24/0x38
process_one_work+0x1d0/0x468
worker_thread+0x238/0x4e0
kthread+0xf0/0x118
ret_from_fork+0x10/0x18

In this case, qed_hw_prepare() returns error due to hw/fw error, but in
theory work queue should be in process context instead of interrupt.

The root cause might be the unpaired spin_{un}lock_bh() in
_qed_mcp_cmd_and_union(), which causes botton half is disabled incorrectly.

Reported-by: Lijian Zhang <Lijian.Zhang@arm.com>
Signed-off-by: Jia He <justin.he@arm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/ethernet/qlogic/qed/qed_mcp.c | 23 +++++++++++++++++------
1 file changed, 17 insertions(+), 6 deletions(-)

diff --git a/drivers/net/ethernet/qlogic/qed/qed_mcp.c b/drivers/net/ethernet/qlogic/qed/qed_mcp.c
index 9401b49275f0..5d85ae59bc51 100644
--- a/drivers/net/ethernet/qlogic/qed/qed_mcp.c
+++ b/drivers/net/ethernet/qlogic/qed/qed_mcp.c
@@ -498,14 +498,18 @@ _qed_mcp_cmd_and_union(struct qed_hwfn *p_hwfn,

spin_lock_bh(&p_hwfn->mcp_info->cmd_lock);

- if (!qed_mcp_has_pending_cmd(p_hwfn))
+ if (!qed_mcp_has_pending_cmd(p_hwfn)) {
+ spin_unlock_bh(&p_hwfn->mcp_info->cmd_lock);
break;
+ }

rc = qed_mcp_update_pending_cmd(p_hwfn, p_ptt);
- if (!rc)
+ if (!rc) {
+ spin_unlock_bh(&p_hwfn->mcp_info->cmd_lock);
break;
- else if (rc != -EAGAIN)
+ } else if (rc != -EAGAIN) {
goto err;
+ }

spin_unlock_bh(&p_hwfn->mcp_info->cmd_lock);

@@ -522,6 +526,8 @@ _qed_mcp_cmd_and_union(struct qed_hwfn *p_hwfn,
return -EAGAIN;
}

+ spin_lock_bh(&p_hwfn->mcp_info->cmd_lock);
+
/* Send the mailbox command */
qed_mcp_reread_offsets(p_hwfn, p_ptt);
seq_num = ++p_hwfn->mcp_info->drv_mb_seq;
@@ -548,14 +554,18 @@ _qed_mcp_cmd_and_union(struct qed_hwfn *p_hwfn,

spin_lock_bh(&p_hwfn->mcp_info->cmd_lock);

- if (p_cmd_elem->b_is_completed)
+ if (p_cmd_elem->b_is_completed) {
+ spin_unlock_bh(&p_hwfn->mcp_info->cmd_lock);
break;
+ }

rc = qed_mcp_update_pending_cmd(p_hwfn, p_ptt);
- if (!rc)
+ if (!rc) {
+ spin_unlock_bh(&p_hwfn->mcp_info->cmd_lock);
break;
- else if (rc != -EAGAIN)
+ } else if (rc != -EAGAIN) {
goto err;
+ }

spin_unlock_bh(&p_hwfn->mcp_info->cmd_lock);
} while (++cnt < max_retries);
@@ -576,6 +586,7 @@ _qed_mcp_cmd_and_union(struct qed_hwfn *p_hwfn,
return -EAGAIN;
}

+ spin_lock_bh(&p_hwfn->mcp_info->cmd_lock);
qed_mcp_cmd_del_elem(p_hwfn, p_cmd_elem);
spin_unlock_bh(&p_hwfn->mcp_info->cmd_lock);

--
2.30.2