Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Mon, 23 Mar 2020 08:10:27 -0700
From:   Jaegeuk Kim <jaegeuk@kernel.org>
To:     Joe Perches <joe@perches.com>
Cc:     Chao Yu <yuchao0@huawei.com>,
        linux-f2fs-devel@lists.sourceforge.net,
        linux-kernel@vger.kernel.org, chao@kernel.org
Subject: Re: [PATCH v5] f2fs: fix potential .flags overflow on 32bit
 architecture
Message-ID: <20200323151027.GA123526@google.com>
References: <20200323031807.94473-1-yuchao0@huawei.com>
 <afa74570dacebb3b93d4b9c27d6c8a87186cef2d.camel@perches.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <afa74570dacebb3b93d4b9c27d6c8a87186cef2d.camel@perches.com>
User-Agent: Mutt/1.12.2 (2019-09-21)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

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.