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Message-ID: <da60f9b8-0ea7-4580-ab45-f294801605f9@huawei.com>
Date: Thu, 14 Mar 2024 19:48:39 +0800
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CC: <shaojijie@huawei.com>, Yisen Zhuang <yisen.zhuang@huawei.com>, Salil
 Mehta <salil.mehta@huawei.com>, "David S. Miller" <davem@davemloft.net>, Eric
 Dumazet <edumazet@google.com>, Jakub Kicinski <kuba@kernel.org>, Paolo Abeni
	<pabeni@redhat.com>, Yufeng Mo <moyufeng@huawei.com>, Huazhong Tan
	<tanhuazhong@huawei.com>
Subject: Re: [PATCH] net: hns3: tracing: fix hclgevf trace event strings
To: Steven Rostedt <rostedt@goodmis.org>, LKML <linux-kernel@vger.kernel.org>,
	Linux Trace Kernel <linux-trace-kernel@vger.kernel.org>, netdev
	<netdev@vger.kernel.org>
References: <20240313093454.3909afe7@gandalf.local.home>
From: Jijie Shao <shaojijie@huawei.com>
In-Reply-To: <20240313093454.3909afe7@gandalf.local.home>
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Reviewed-by: Jijie Shao<shaojijie@huawei.com>

on 2024/3/13 21:34, Steven Rostedt wrote:
> From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
>
> [
>     Note, I need to take this patch through my tree, so I'm looking for acks.
>     This causes the build to fail when I add the __assign_str() check, which
>     I was about to push to Linus, but it breaks allmodconfig due to this error.
> ]
>
> The __string() and __assign_str() helper macros of the TRACE_EVENT() macro
> are going through some optimizations where only the source string of
> __string() will be used and the __assign_str() source will be ignored and
> later removed.
>
> To make sure that there's no issues, a new check is added between the
> __string() src argument and the __assign_str() src argument that does a
> strcmp() to make sure they are the same string.
>
> The hclgevf trace events have:
>
>    __assign_str(devname, &hdev->nic.kinfo.netdev->name);
>
> Which triggers the warning:
>
> hclgevf_trace.h:34:39: error: passing argument 1 of ‘strcmp’ from incompatible pointer type [-Werror=incompatible-pointer-types]
>     34 |                 __assign_str(devname, &hdev->nic.kinfo.netdev->name);
>   [..]
> arch/x86/include/asm/string_64.h:75:24: note: expected ‘const char *’ but argument is of type ‘char (*)[16]’
>     75 | int strcmp(const char *cs, const char *ct);
>        |            ~~~~~~~~~~~~^~
>
>
> Because __assign_str() now has:
>
> 	WARN_ON_ONCE(__builtin_constant_p(src) ?		\
> 		     strcmp((src), __data_offsets.dst##_ptr_) :	\
> 		     (src) != __data_offsets.dst##_ptr_);	\
>
> The problem is the '&' on hdev->nic.kinfo.netdev->name. That's because
> that name is:
>
> 	char			name[IFNAMSIZ]
>
> Where passing an address '&' of a char array is not compatible with strcmp().
>
> The '&' is not necessary, remove it.
>
> Fixes: d8355240cf8fb ("net: hns3: add trace event support for PF/VF mailbox")
> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
> ---
>   drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_trace.h  | 8 ++++----
>   .../net/ethernet/hisilicon/hns3/hns3vf/hclgevf_trace.h    | 8 ++++----
>   2 files changed, 8 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_trace.h b/drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_trace.h
> index 8510b88d4982..f3cd5a376eca 100644
> --- a/drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_trace.h
> +++ b/drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_trace.h
> @@ -24,7 +24,7 @@ TRACE_EVENT(hclge_pf_mbx_get,
>   		__field(u8, code)
>   		__field(u8, subcode)
>   		__string(pciname, pci_name(hdev->pdev))
> -		__string(devname, &hdev->vport[0].nic.kinfo.netdev->name)
> +		__string(devname, hdev->vport[0].nic.kinfo.netdev->name)
>   		__array(u32, mbx_data, PF_GET_MBX_LEN)
>   	),
>   
> @@ -33,7 +33,7 @@ TRACE_EVENT(hclge_pf_mbx_get,
>   		__entry->code = req->msg.code;
>   		__entry->subcode = req->msg.subcode;
>   		__assign_str(pciname, pci_name(hdev->pdev));
> -		__assign_str(devname, &hdev->vport[0].nic.kinfo.netdev->name);
> +		__assign_str(devname, hdev->vport[0].nic.kinfo.netdev->name);
>   		memcpy(__entry->mbx_data, req,
>   		       sizeof(struct hclge_mbx_vf_to_pf_cmd));
>   	),
> @@ -56,7 +56,7 @@ TRACE_EVENT(hclge_pf_mbx_send,
>   		__field(u8, vfid)
>   		__field(u16, code)
>   		__string(pciname, pci_name(hdev->pdev))
> -		__string(devname, &hdev->vport[0].nic.kinfo.netdev->name)
> +		__string(devname, hdev->vport[0].nic.kinfo.netdev->name)
>   		__array(u32, mbx_data, PF_SEND_MBX_LEN)
>   	),
>   
> @@ -64,7 +64,7 @@ TRACE_EVENT(hclge_pf_mbx_send,
>   		__entry->vfid = req->dest_vfid;
>   		__entry->code = le16_to_cpu(req->msg.code);
>   		__assign_str(pciname, pci_name(hdev->pdev));
> -		__assign_str(devname, &hdev->vport[0].nic.kinfo.netdev->name);
> +		__assign_str(devname, hdev->vport[0].nic.kinfo.netdev->name);
>   		memcpy(__entry->mbx_data, req,
>   		       sizeof(struct hclge_mbx_pf_to_vf_cmd));
>   	),
> diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3vf/hclgevf_trace.h b/drivers/net/ethernet/hisilicon/hns3/hns3vf/hclgevf_trace.h
> index 5d4895bb57a1..b259e95dd53c 100644
> --- a/drivers/net/ethernet/hisilicon/hns3/hns3vf/hclgevf_trace.h
> +++ b/drivers/net/ethernet/hisilicon/hns3/hns3vf/hclgevf_trace.h
> @@ -23,7 +23,7 @@ TRACE_EVENT(hclge_vf_mbx_get,
>   		__field(u8, vfid)
>   		__field(u16, code)
>   		__string(pciname, pci_name(hdev->pdev))
> -		__string(devname, &hdev->nic.kinfo.netdev->name)
> +		__string(devname, hdev->nic.kinfo.netdev->name)
>   		__array(u32, mbx_data, VF_GET_MBX_LEN)
>   	),
>   
> @@ -31,7 +31,7 @@ TRACE_EVENT(hclge_vf_mbx_get,
>   		__entry->vfid = req->dest_vfid;
>   		__entry->code = le16_to_cpu(req->msg.code);
>   		__assign_str(pciname, pci_name(hdev->pdev));
> -		__assign_str(devname, &hdev->nic.kinfo.netdev->name);
> +		__assign_str(devname, hdev->nic.kinfo.netdev->name);
>   		memcpy(__entry->mbx_data, req,
>   		       sizeof(struct hclge_mbx_pf_to_vf_cmd));
>   	),
> @@ -55,7 +55,7 @@ TRACE_EVENT(hclge_vf_mbx_send,
>   		__field(u8, code)
>   		__field(u8, subcode)
>   		__string(pciname, pci_name(hdev->pdev))
> -		__string(devname, &hdev->nic.kinfo.netdev->name)
> +		__string(devname, hdev->nic.kinfo.netdev->name)
>   		__array(u32, mbx_data, VF_SEND_MBX_LEN)
>   	),
>   
> @@ -64,7 +64,7 @@ TRACE_EVENT(hclge_vf_mbx_send,
>   		__entry->code = req->msg.code;
>   		__entry->subcode = req->msg.subcode;
>   		__assign_str(pciname, pci_name(hdev->pdev));
> -		__assign_str(devname, &hdev->nic.kinfo.netdev->name);
> +		__assign_str(devname, hdev->nic.kinfo.netdev->name);
>   		memcpy(__entry->mbx_data, req,
>   		       sizeof(struct hclge_mbx_vf_to_pf_cmd));
>   	),