Re: [kbuild-all] Re: [PATCH next 2/3] debugfs: introduce debugfs_create_single[,_data]

[Rong Chen]

On 12/3/19 4:38 PM, Dan Carpenter wrote:
> [ How do I fetch 0day git branchs?
>    git fetch https://github.com/0day-ci/linux/commits/Kefeng-Wang/debugfs-introduce-debugfs_create_single-seq-_data/20191129-173440
>    doesn't work. - dan ]

Hi Dan,

I can fetch it by the following steps:

nfs@shao2-debian:~/linux$ git remote add 0day-linux-review 
https://github.com/0day-ci/linux.git
nfs@shao2-debian:~/linux$ git fetch --no-tags 0day-linux-review 
Kefeng-Wang/debugfs-introduce-debugfs_create_single-seq-_data/20191129-173440 

remote: Enumerating objects: 25261, done.
remote: Counting objects: 100% (25261/25261), done.
remote: Total 33246 (delta 25260), reused 25260 (delta 25260), 
pack-reused 7985
Receiving objects: 100% (33246/33246), 12.03 MiB | 1.05 MiB/s, done.
Resolving deltas: 100% (28148/28148), completed with 6149 local objects.
From https://github.com/0day-ci/linux
Â* branch 
Kefeng-Wang/debugfs-introduce-debugfs_create_single-seq-_data/20191129-173440 
-> FETCH_HEAD
Â* [new branch] 
Kefeng-Wang/debugfs-introduce-debugfs_create_single-seq-_data/20191129-173440 
-> 
0day-linux-review/Kefeng-Wang/debugfs-introduce-debugfs_create_single-seq-_data/20191129-173440

Best Regards,
Rong Chen

> Hi Kefeng,
>
> Thank you for the patch! Perhaps something to improve:
>
> [auto build test WARNING on next-20191128]
> [cannot apply to v5.4]
> [if your patch is applied to the wrong git tree, please drop us a note to help
> improve the system. BTW, we also suggest to use '--base' option to specify the
> base tree in git format-patch, please see https://stackoverflow.com/a/37406982]
>
> url:    https://github.com/0day-ci/linux/commits/Kefeng-Wang/debugfs-introduce-debugfs_create_single-seq-_data/20191129-173440
> base:    d26b0e226f222c22c3b7e9d16e5b886e7c51057a
>
>
> If you fix the issue, kindly add following tag
> Reported-by: kbuild test robot <lkp@xxxxxxxxx>
> Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
>
> New smatch warnings:
> fs/debugfs/file.c:1193 debugfs_create_single_data() warn: overwrite may leak 'entry'
>
> Old smatch warnings:
> include/linux/compiler.h:247 __write_once_size() warn: potential memory corrupting cast 8 vs 4 bytes
>
> # https://github.com/0day-ci/linux/commit/198a4ea9768d6790a169e8b802e702c208aafbd1
> git remote add linux-review https://github.com/0day-ci/linux
> git remote update linux-review
> git checkout 198a4ea9768d6790a169e8b802e702c208aafbd1
> vim +/entry +1193 fs/debugfs/file.c
>
> 198a4ea9768d67 Kefeng Wang      2019-11-29  1179  struct dentry *debugfs_create_single_data(const char *name, umode_t mode,
> 198a4ea9768d67 Kefeng Wang      2019-11-29  1180  					  struct dentry *parent, void *data,
> 198a4ea9768d67 Kefeng Wang      2019-11-29  1181  					  int (*read_fn)(struct seq_file *s,
> 198a4ea9768d67 Kefeng Wang      2019-11-29  1182  							 void *data))
> 198a4ea9768d67 Kefeng Wang      2019-11-29  1183  {
> 198a4ea9768d67 Kefeng Wang      2019-11-29  1184  	struct debugfs_entry *entry;
> 198a4ea9768d67 Kefeng Wang      2019-11-29  1185
> 198a4ea9768d67 Kefeng Wang      2019-11-29  1186  	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
> 198a4ea9768d67 Kefeng Wang      2019-11-29  1187  	if (!entry)
> 198a4ea9768d67 Kefeng Wang      2019-11-29  1188  		return ERR_PTR(-ENOMEM);
> 198a4ea9768d67 Kefeng Wang      2019-11-29  1189
> 198a4ea9768d67 Kefeng Wang      2019-11-29  1190  	entry->read = read_fn;
> 198a4ea9768d67 Kefeng Wang      2019-11-29  1191  	entry->data = data;
> 198a4ea9768d67 Kefeng Wang      2019-11-29  1192
> 198a4ea9768d67 Kefeng Wang      2019-11-29 @1193  	entry = debugfs_set_lowest_bit(entry);
>                                                          ^^^^^^^^
> I haven't looked at the surrounding code but how would we free "entry"
> when we write over it here?
>
> ---
> 0-DAY kernel test infrastructure                 Open Source Technology Center
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