On 2020/3/23 10:00, Joe Perches wrote:
> On Mon, 2020-03-23 at 09:25 +0800, Chao Yu wrote:
>> f2fs_inode_info.flags is unsigned long variable, it has 32 bits
>> in 32bit architecture, since we introduced FI_MMAP_FILE flag
>> when we support data compression, we may access memory cross
>> the border of .flags field, corrupting .i_sem field, result in
>> below deadlock.
>>
>> To fix this issue, let's expand .flags as an array to grab enough
>> space to store new flags.
> []
>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> []
>> @@ -2586,22 +2590,28 @@ static inline void __mark_inode_dirty_flag(struct
>> inode *inode,
>> }
>> }
>>
>> +static inline void __set_inode_flag(struct inode *inode, int flag)
>> +{
>> + test_and_set_bit(flag % BITS_PER_LONG,
>> + &F2FS_I(inode)->flags[BIT_WORD(flag)]);
>
> I believe this should just use
>
> test_and_set_bit(flag, F2FS_I(inode)->flags);
>
>> static inline int is_inode_flag_set(struct inode *inode, int flag)
>> {
>> - return test_bit(flag, &F2FS_I(inode)->flags);
>> + return test_bit(flag % BITS_PER_LONG,
>> + &F2FS_I(inode)->flags[BIT_WORD(flag)]);
>
> here too.
>
> test_bit(flag, F2FS_I(inode)->flags);
>
>> static inline void clear_inode_flag(struct inode *inode, int flag)
>> {
>> - if (test_bit(flag, &F2FS_I(inode)->flags))
>> - clear_bit(flag, &F2FS_I(inode)->flags);
>> + test_and_clear_bit(flag % BITS_PER_LONG,
>> + &F2FS_I(inode)->flags[BIT_WORD(flag)]);
>
> and here.
My bad, Ondřej Jirman also reminded me this issue, will fix this soon.
Thanks,
>
> I also don't know why these functions are used at all.
>
>
> .
>
_______________________________________________
Linux-f2fs-devel mailing list
Linux-f2fs-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
