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From: Jia He <justin.he@arm.com>
To: Ariel Elior <aelior@marvell.com>,
	GR-everest-linux-l2@marvell.com,
	"David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>
Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, nd@arm.com,
	Jia He <justin.he@arm.com>
Subject: [PATCH] qed: fix possible unpaired spin_{un}lock_bh in _qed_mcp_cmd_and_union()
Date: Thu, 15 Jul 2021 16:08:21 +0800	[thread overview]
Message-ID: <20210715080822.14575-1-justin.he@arm.com> (raw)

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>
---
 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 4387292c37e2..79d879a5d663 100644
--- a/drivers/net/ethernet/qlogic/qed/qed_mcp.c
+++ b/drivers/net/ethernet/qlogic/qed/qed_mcp.c
@@ -474,14 +474,18 @@ _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);
 
@@ -498,6 +502,8 @@ _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;
@@ -524,14 +530,18 @@ _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);
@@ -554,6 +564,7 @@ _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);
 
-- 
2.17.1


             reply	other threads:[~2021-07-15  8:08 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-15  8:08 Jia He [this message]
2021-07-15 19:50 ` [PATCH] qed: fix possible unpaired spin_{un}lock_bh in _qed_mcp_cmd_and_union() patchwork-bot+netdevbpf
2021-07-15 23:42   ` Justin He
2021-07-19 10:35 ` Prabhakar Kushwaha
2021-07-19 13:16   ` Justin He
2021-07-19 14:50     ` Prabhakar Kushwaha
2021-07-20  2:02       ` Justin He
2021-07-20  9:05         ` Jakub Kicinski
2021-07-20  9:28           ` Justin He

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