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

[Jaegeuk Kim]

On 03/23, Joe Perches wrote:
> 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);

Thanks, I applied this directly in the f2fs tree.