Re: [External] : [syzbot] [ocfs2?] BUG: unable to handle kernel paging request in ocfs2_unlock_and_free_folios

[Mark Tinguely <mark.tinguely@oracle.com>]

 > The reproducer uses FAULT_INJECTION to make memory allocation fail, which
 > causes __filemap_get_folio() to fail, when initializing w_folios[i] in
 > ocfs2_grab_folios_for_write(), it only returns an error code and the 
value
 > of w_folios[i] is the error code, which causes 
ocfs2_unlock_and_free_folios()
 > to recycle the invalid w_folios[i] when releasing folios.
 >
 > Reported-by: syzbot+c2ea94ae47cd7e3881ec@syzkaller.appspotmail.com
 > Closes: https://syzkaller.appspot.com/bug?extid=c2ea94ae47cd7e3881ec
 > Signed-off-by: Lizhi Xu <lizhi.xu@windriver.com>
 > ---
 >  fs/ocfs2/aops.c | 1 +
 >  1 file changed, 1 insertion(+)
 >
 > diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
 > index 40b6bce12951..89aadc6cdd87 100644
 > --- a/fs/ocfs2/aops.c
 > +++ b/fs/ocfs2/aops.c
 > @@ -1071,6 +1071,7 @@ static int ocfs2_grab_folios_for_write(struct 
address_space *mapping,
 >  			if (IS_ERR(wc->w_folios[i])) {
 >  				ret = PTR_ERR(wc->w_folios[i]);
 >  				mlog_errno(ret);
 > +				wc->w_folios[i] = NULL;
 >  				goto out;
 >  			}
 >  		}
 > --
 > 2.43.0

sorry for the cut and paste reply. My email system rejected and bounced 
the original email.

ACKed-by: Mark Tinguely <mark.tinguely@oracle.com>