linux-kernel - Re: [PATCH v3] bcachefs: init freespace inited bits to 0 in bch2_fs

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <xjjlqqfu6oulfdndotkwr57z7adt6gaq26g67iiy7qv2pk3wv3@y6hv3sr7smjz>
Date: Sat, 26 Oct 2024 20:31:24 -0400
From: Kent Overstreet <kent.overstreet@...ux.dev>
To: Piotr Zalewski <pZ010001011111@...ton.me>
Cc: linux-bcachefs@...r.kernel.org, linux-kernel@...r.kernel.org, 
	skhan@...uxfoundation.org, syzbot+2b6a17991a6af64f9489@...kaller.appspotmail.com
Subject: Re: [PATCH v3] bcachefs: init freespace inited bits to 0 in
 bch2_fs_initialize

On Sat, Oct 26, 2024 at 01:40:47PM +0000, Piotr Zalewski wrote:
> On Saturday, October 26th, 2024 at 2:30 AM, Kent Overstreet <kent.overstreet@...ux.dev> wrote:
> 
> > On Sat, Oct 26, 2024 at 12:15:49AM +0000, Piotr Zalewski wrote:
> > 
> > > Initialize freespace_initialized bits to 0 in member's flags and update
> > > member's cached version for each device in bch2_fs_initialize.
> > > 
> > > It's possible for the bits to be set to 1 before fs is initialized and if
> > > call to bch2_trans_mark_dev_sbs (just before bch2_fs_freespace_init) fails
> > > bits remain to be 1 which can later indirectly trigger BUG condition in
> > > bch2_bucket_alloc_freelist during shutdown.
> > > 
> > > Reported-by: syzbot+2b6a17991a6af64f9489@...kaller.appspotmail.com
> > > Closes: https://syzkaller.appspot.com/bug?extid=2b6a17991a6af64f9489
> > > Fixes: bbe682c76789 ("bcachefs: Ensure devices are always correctly initialized")
> > > Suggested-by: Kent Overstreet kent.overstreet@...ux.dev
> > > Signed-off-by: Piotr Zalewski pZ010001011111@...ton.me
> > > ---
> > > 
> > > Notes:
> > > changes in v3:
> > > - v2 rebased
> > > 
> > > changes in v2:
> > > - unconditionally set freespace initialized bits to false at
> > > the top of bch2_fs_initialized instead of only if
> > > bch2_trans_mark_dev_sbs fails
> > > 
> > > Link to v2: https://lore.kernel.org/linux-bcachefs/20241021174151.37692-2-pZ010001011111@proton.me/
> > > Link to v1: https://lore.kernel.org/linux-bcachefs/20241020170708.67044-2-pZ010001011111@proton.me/
> > > 
> > > fs/bcachefs/recovery.c | 8 ++++++++
> > > 1 file changed, 8 insertions(+)
> > > 
> > > diff --git a/fs/bcachefs/recovery.c b/fs/bcachefs/recovery.c
> > > index fdf2aa2ffc13..8d4c93a1f5aa 100644
> > > --- a/fs/bcachefs/recovery.c
> > > +++ b/fs/bcachefs/recovery.c
> > > @@ -1029,6 +1029,7 @@ int bch2_fs_initialize(struct bch_fs *c)
> > > struct bch_inode_unpacked root_inode, lostfound_inode;
> > > struct bkey_inode_buf packed_inode;
> > > struct qstr lostfound = QSTR("lost+found");
> > > + struct bch_member *m;
> > > int ret;
> > > 
> > > bch_notice(c, "initializing new filesystem");
> > > @@ -1045,6 +1046,13 @@ int bch2_fs_initialize(struct bch_fs *c)
> > > SET_BCH_SB_VERSION_UPGRADE_COMPLETE(c->disk_sb.sb, bcachefs_metadata_version_current);
> > > bch2_write_super(c);
> > > }
> > > +
> > > + for_each_member_device(c, ca) {
> > > + m = bch2_members_v2_get_mut(c->disk_sb.sb, ca->dev_idx);
> > > + SET_BCH_MEMBER_FREESPACE_INITIALIZED(m, false);
> > > + ca->mi = bch2_mi_to_cpu(m);
> > > + }
> > > +
> > 
> > 
> > I'm also adding a write_super() call here: that's what updates
> > ca->mi.freespace_initialized which the freespace init path will later
> > 
> > check.
> 
> Do you want me to send v4? Or you will add it with separate patch?

I did it as a fixup to your patch