Re: [PATCH v5] f2fs: fix potential .flags overflow on 32bit architecture

[Joe Perches]

On Mon, 2020-03-23 at 11:18 +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.
[]
> diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
[]
> @@ -362,7 +362,7 @@ static int do_read_inode(struct inode *inode)
>  	fi->i_flags = le32_to_cpu(ri->i_flags);
>  	if (S_ISREG(inode->i_mode))
>  		fi->i_flags &= ~F2FS_PROJINHERIT_FL;
> -	fi->flags = 0;
> +	bitmap_zero(fi->flags, BITS_TO_LONGS(FI_MAX));

Sorry, I misled you here, this should be

	bitmap_zero(fi->flags, FI_MAX);