Hi, Sasha
> -----Original Message-----
> From: Sasha Levin <sashal@xxxxxxxxxx>
> Sent: Tuesday, July 27, 2021 9:19 PM
> To: linux-kernel@xxxxxxxxxxxxxxx; stable@xxxxxxxxxxxxxxx
> Cc: Justin He <Justin.He@xxxxxxx>; Lijian Zhang <Lijian.Zhang@xxxxxxx>;
> David S . Miller <davem@xxxxxxxxxxxxx>; Sasha Levin <sashal@xxxxxxxxxx>;
> netdev@xxxxxxxxxxxxxxx
> Subject: [PATCH AUTOSEL 5.13 09/21] qed: fix possible unpaired
> spin_{un}lock_bh in _qed_mcp_cmd_and_union()
>
> From: Jia He <justin.he@xxxxxxx>
If possible, please stop taking this commit to any stable version because
it has been reverted by later commit.
This patch is harmless but pointless.
Sorry for the inconvenience.
--
Cheers,
Justin (Jia He)
>
> [ 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@xxxxxxx>
> Signed-off-by: Jia He <justin.he@xxxxxxx>
> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
> ---
> 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 cd882c453394..caeef25c89bb 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);
>
> --
> 2.30.2
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