On 2020/11/29 3:36, Jakub Kicinski wrote:

On Sat, 28 Nov 2020 16:20:54 +1100 Stephen Rothwell wrote:

quoted

On Fri, 27 Nov 2020 17:56:42 -0800 Jakub Kicinski [off-list ref] wrote:

quoted

What's the offending structure in hisilicon? I'd rather have a look
packing structs with pointers in 'em sounds questionable.

I only see these two:

$ git grep packed drivers/net/ethernet/hisilicon/
drivers/net/ethernet/hisilicon/hns/hnae.h:struct __packed hnae_desc {
drivers/net/ethernet/hisilicon/hns3/hns3_enet.h:struct __packed hns3_desc {  

struct hclge_dbg_reg_type_info which is 28 bytes long due to the
included struct struct hclge_dbg_reg_common_msg (which is 12 bytes
long).  They are surrounded by #pragma pack(1)/pack().

This forces the 2 pointers in each second array element of
hclge_dbg_reg_info[] to be 4 byte aligned (where pointers are 8 bytes
long on PPC64).

Ah! Thanks, I don't see a reason for these to be packed. 
Looks  like an accident, there is no reason to pack anything 
past struct hclge_dbg_reg_common_msg AFAICT.

Huawei folks, would you mind sending a fix if the analysis is correct?

Yes, will send a patch to fix that. Thanks for the analysis.

.