Re: [PATCH] fs/ntfs: fix BUG_ON of ntfs_read_block()

[CGEL]

On Thu, Jun 23, 2022 at 09:57:21AM +0200, Greg KH wrote:
> On Thu, Jun 23, 2022 at 03:51:31AM +0000, cgel.zte@xxxxxxxxx wrote:
> > From: xu xin <xu.xin16@xxxxxxxxxx>
> > 
> > As the bug description, attckers can use this bug to crash the system
> > When CONFIG_NTFS_FS is set.
> > 
> > So remove the BUG_ON, and use WARN and return instead until someone
> > really solve the bug.
> > 
> > Reported-by: Zeal Robot <zealci@xxxxxxxxxx>
> > Reported-by: syzbot+6a5a7672f663cce8b156@xxxxxxxxxxxxxxxxxxxxxxxxx
> > Reviewed-by: Songyi Zhang <zhang.songyi@xxxxxxxxxx>
> > Reviewed-by: Yang Yang <yang.yang29@xxxxxxxxxx>
> > Reviewed-by: Jiang Xuexin<jiang.xuexin@xxxxxxxxxx>
> > Reviewed-by: Zhang wenya<zhang.wenya1@xxxxxxxxxx>
> > Signed-off-by: xu xin <xu.xin16@xxxxxxxxxx>
> > ---
> >  fs/ntfs/aops.c | 6 +++++-
> >  1 file changed, 5 insertions(+), 1 deletion(-)
> > 
> > diff --git a/fs/ntfs/aops.c b/fs/ntfs/aops.c
> > index 5f4fb6ca6f2e..b6fd7e711420 100644
> > --- a/fs/ntfs/aops.c
> > +++ b/fs/ntfs/aops.c
> > @@ -183,7 +183,11 @@ static int ntfs_read_block(struct page *page)
> >  	vol = ni->vol;
> >  
> >  	/* $MFT/$DATA must have its complete runlist in memory at all times. */
> > -	BUG_ON(!ni->runlist.rl && !ni->mft_no && !NInoAttr(ni));
> > +	if (unlikely(!ni->runlist.rl && !ni->mft_no && !NInoAttr(ni))) {
> > +		WARN(1, "NTFS: ni->runlist.rl, ni->mft_no, and NInoAttr(ni) is null!\n");
> 
> So for systems with panic-on-warn, you are still crashing?  Why is this
> WARN() line still needed here?
>

Sorry, I forgot about panic-on-warn. Use pr_warn() may be better.
I'll send a patch-v2 .

> thanks,
> 
> greg k-h