Re: [f2fs-dev] [bug report] compiler warning: fs/f2fs/node.c: In function â__set_nat_cache_dirtyâ: âheadâ may be used uninitialized

[Chao Yu]

On 2019/10/23 22:02, Ardelean, Alexandru wrote:
> Seems to have been introduced via:
> 
> ----------------------------------------------------------------
> 
> commit 780de47cf6cb5f524cd98ec8ffbffc3da5696e17
> Author: Chao Yu <yuchao0@xxxxxxxxxx>
> Date:   Tue Mar 20 23:08:30 2018 +0800
> 
>     f2fs: don't track new nat entry in nat set
>     
>     Nat entry set is used only in checkpoint(), and during checkpoint() we
>     won't flush new nat entry with unallocated address, so we don't need to
>     add new nat entry into nat set, then nat_entry_set::entry_cnt can
>     indicate actual entry count we need to flush in checkpoint().
>     
>     Signed-off-by: Yunlei He <heyunlei@xxxxxxxxxx>
>     Signed-off-by: Chao Yu <yuchao0@xxxxxxxxxx>
>     Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
> ----------------------------------------------------------------
> 
> Compiler warning is:
> ----------------------------------------------------------------
> 
>   CC      fs/f2fs/node.o
> In file included from ./include/linux/wait.h:7:0,
>                  from ./include/linux/wait_bit.h:8,
>                  from ./include/linux/fs.h:6,
>                  from fs/f2fs/node.c:11:
> fs/f2fs/node.c: In function â__set_nat_cache_dirtyâ:
> ./include/linux/list.h:63:13: error: âheadâ may be used uninitialized in
> this function [-Werror=maybe-uninitialized]
>   next->prev = new;
>              ^
> fs/f2fs/node.c:238:24: note: âheadâ was declared here
>   struct nat_entry_set *head;

That's not correct, @head will only be assigned and used if new_ne equals NULL.

Thanks,

>                         ^
> cc1: all warnings being treated as errors
> ----------------------------------------------------------------
> 
> Thanks
> Alex
> 
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