Re: [PATCH 1/1] net/mlx4_core: avoid resetting HCA when accessing an offline device
From: Zhu Yanjun Date: Sun, 15 Apr 2018 21:02:07 -0400 > While a faulty cable is used or HCA firmware error, HCA device will > be offline. When the driver is accessing this offline device, the > following call trace will pop out. ... > In the above call trace, the function mlx4_cmd_poll calls the function > mlx4_cmd_post to access the HCA while HCA is offline. Then mlx4_cmd_post > returns an error -EIO. Per -EIO, the function mlx4_cmd_poll calls > mlx4_cmd_reset_flow to reset HCA. And the above call trace pops out. > > This is not reasonable. Since HCA device is offline when it is being > accessed, it should not be reset again. > > In this patch, since HCA is offline, the function mlx4_cmd_post returns > an error -EINVAL. Per -EINVAL, the function mlx4_cmd_poll directly returns > instead of resetting HCA. > > CC: Srinivas Eeda > CC: Junxiao Bi > Suggested-by: Håkon Bugge > Signed-off-by: Zhu Yanjun Tariq, I'm assuming you'll take this in and send it to me later. Thanks.
Re: [PATCH 1/1] net/mlx4_core: avoid resetting HCA when accessing an offline device
On 16/04/2018 7:51 PM, David Miller wrote: From: Zhu Yanjun Date: Sun, 15 Apr 2018 21:02:07 -0400 While a faulty cable is used or HCA firmware error, HCA device will be offline. When the driver is accessing this offline device, the following call trace will pop out. ... In the above call trace, the function mlx4_cmd_poll calls the function mlx4_cmd_post to access the HCA while HCA is offline. Then mlx4_cmd_post returns an error -EIO. Per -EIO, the function mlx4_cmd_poll calls mlx4_cmd_reset_flow to reset HCA. And the above call trace pops out. This is not reasonable. Since HCA device is offline when it is being accessed, it should not be reset again. In this patch, since HCA is offline, the function mlx4_cmd_post returns an error -EINVAL. Per -EINVAL, the function mlx4_cmd_poll directly returns instead of resetting HCA. CC: Srinivas Eeda CC: Junxiao Bi Suggested-by: Håkon Bugge Signed-off-by: Zhu Yanjun Tariq, I'm assuming you'll take this in and send it to me later. Thanks. Yes, I will review and send if all is OK. Thanks, Tariq -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH 1/1] net/mlx4_core: avoid resetting HCA when accessing an offline device
On 16/04/2018 4:02 AM, Zhu Yanjun wrote: While a faulty cable is used or HCA firmware error, HCA device will be offline. When the driver is accessing this offline device, the following call trace will pop out. " ... [] dump_stack+0x63/0x81 [] panic+0xcc/0x21b [] mlx4_enter_error_state+0xba/0xf0 [mlx4_core] [] mlx4_cmd_reset_flow+0x38/0x60 [mlx4_core] [] mlx4_cmd_poll+0xc1/0x2e0 [mlx4_core] [] __mlx4_cmd+0xb0/0x160 [mlx4_core] [] mlx4_SENSE_PORT+0x54/0xd0 [mlx4_core] [] mlx4_dev_cap+0x4a4/0xb50 [mlx4_core] ... " In the above call trace, the function mlx4_cmd_poll calls the function mlx4_cmd_post to access the HCA while HCA is offline. Then mlx4_cmd_post returns an error -EIO. Per -EIO, the function mlx4_cmd_poll calls mlx4_cmd_reset_flow to reset HCA. And the above call trace pops out. This is not reasonable. Since HCA device is offline when it is being accessed, it should not be reset again. In this patch, since HCA is offline, the function mlx4_cmd_post returns an error -EINVAL. Per -EINVAL, the function mlx4_cmd_poll directly returns instead of resetting HCA. CC: Srinivas Eeda CC: Junxiao Bi Suggested-by: Håkon Bugge Signed-off-by: Zhu Yanjun --- drivers/net/ethernet/mellanox/mlx4/cmd.c | 8 1 file changed, 8 insertions(+) diff --git a/drivers/net/ethernet/mellanox/mlx4/cmd.c b/drivers/net/ethernet/mellanox/mlx4/cmd.c index 6a9086d..f1c8c42 100644 --- a/drivers/net/ethernet/mellanox/mlx4/cmd.c +++ b/drivers/net/ethernet/mellanox/mlx4/cmd.c @@ -451,6 +451,8 @@ static int mlx4_cmd_post(struct mlx4_dev *dev, u64 in_param, u64 out_param, * Device is going through error recovery * and cannot accept commands. */ + mlx4_err(dev, "%s : Device is in error recovery.\n", __func__); + ret = -EINVAL; goto out; } @@ -657,6 +659,9 @@ static int mlx4_cmd_poll(struct mlx4_dev *dev, u64 in_param, u64 *out_param, } out_reset: + if (err == -EINVAL) + goto out; + See below. if (err) err = mlx4_cmd_reset_flow(dev, op, op_modifier, err); out: @@ -766,6 +771,9 @@ static int mlx4_cmd_wait(struct mlx4_dev *dev, u64 in_param, u64 *out_param, *out_param = context->out_param; out_reset: + if (err == -EINVAL) + goto out; + if (err) Instead, just do here: if (err && err != -EINVAL) err = mlx4_cmd_reset_flow(dev, op, op_modifier, err); out: I am not sure this does not mistakenly cover other cases that already exist and have (err == -EINVAL). For example, this line is hard to predict: err = mlx4_status_to_errno and later on, we might get into if (mlx4_closing_cmd_fatal_error(op, stat)) which leads to out_reset. We must have a deeper look at this. But a better option is, change the error indication to uniquely indicate "already in error recovery".
Re: [PATCH 1/1] net/mlx4_core: avoid resetting HCA when accessing an offline device
On 2018/4/17 23:37, Tariq Toukan wrote: On 16/04/2018 4:02 AM, Zhu Yanjun wrote: While a faulty cable is used or HCA firmware error, HCA device will be offline. When the driver is accessing this offline device, the following call trace will pop out. " ... [] dump_stack+0x63/0x81 [] panic+0xcc/0x21b [] mlx4_enter_error_state+0xba/0xf0 [mlx4_core] [] mlx4_cmd_reset_flow+0x38/0x60 [mlx4_core] [] mlx4_cmd_poll+0xc1/0x2e0 [mlx4_core] [] __mlx4_cmd+0xb0/0x160 [mlx4_core] [] mlx4_SENSE_PORT+0x54/0xd0 [mlx4_core] [] mlx4_dev_cap+0x4a4/0xb50 [mlx4_core] ... " In the above call trace, the function mlx4_cmd_poll calls the function mlx4_cmd_post to access the HCA while HCA is offline. Then mlx4_cmd_post returns an error -EIO. Per -EIO, the function mlx4_cmd_poll calls mlx4_cmd_reset_flow to reset HCA. And the above call trace pops out. This is not reasonable. Since HCA device is offline when it is being accessed, it should not be reset again. In this patch, since HCA is offline, the function mlx4_cmd_post returns an error -EINVAL. Per -EINVAL, the function mlx4_cmd_poll directly returns instead of resetting HCA. CC: Srinivas Eeda CC: Junxiao Bi Suggested-by: Håkon Bugge Signed-off-by: Zhu Yanjun --- drivers/net/ethernet/mellanox/mlx4/cmd.c | 8 1 file changed, 8 insertions(+) diff --git a/drivers/net/ethernet/mellanox/mlx4/cmd.c b/drivers/net/ethernet/mellanox/mlx4/cmd.c index 6a9086d..f1c8c42 100644 --- a/drivers/net/ethernet/mellanox/mlx4/cmd.c +++ b/drivers/net/ethernet/mellanox/mlx4/cmd.c @@ -451,6 +451,8 @@ static int mlx4_cmd_post(struct mlx4_dev *dev, u64 in_param, u64 out_param, * Device is going through error recovery * and cannot accept commands. */ + mlx4_err(dev, "%s : Device is in error recovery.\n", __func__); + ret = -EINVAL; goto out; } @@ -657,6 +659,9 @@ static int mlx4_cmd_poll(struct mlx4_dev *dev, u64 in_param, u64 *out_param, } out_reset: + if (err == -EINVAL) + goto out; + See below. if (err) err = mlx4_cmd_reset_flow(dev, op, op_modifier, err); out: @@ -766,6 +771,9 @@ static int mlx4_cmd_wait(struct mlx4_dev *dev, u64 in_param, u64 *out_param, *out_param = context->out_param; out_reset: + if (err == -EINVAL) + goto out; + if (err) Instead, just do here: if (err && err != -EINVAL) err = mlx4_cmd_reset_flow(dev, op, op_modifier, err); out: I am not sure this does not mistakenly cover other cases that already exist and have (err == -EINVAL). For example, this line is hard to predict: err = mlx4_status_to_errno and later on, we might get into if (mlx4_closing_cmd_fatal_error(op, stat)) which leads to out_reset. Thanks a lot. Sure. I agree with you that "err = mlx4_status_to_errno" and "if (mlx4_closing_cmd_fatal_error(op, stat))" will also make "err=-EINVAL". This will mistakenly go to out instead of resetting HCA device. I will make a new patch to avoid the above error. Zhu Yanjun We must have a deeper look at this. But a better option is, change the error indication to uniquely indicate "already in error recovery".