FAILED: patch "[PATCH] btrfs: fix log context list corruption after rename whiteout" failed to apply to 4.14-stable tree

FAILED: patch "[PATCH] btrfs: fix log context list corruption after rename whiteout" failed to apply to 4.14-stable tree

[gregkh]

The patch below does not apply to the 4.14-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 236ebc20d9afc5e9ff52f3cf3f365a91583aac10 Mon Sep 17 00:00:00 2001
From: Filipe Manana <fdmanana@suse.com>
Date: Tue, 10 Mar 2020 12:13:53 +0000
Subject: [PATCH] btrfs: fix log context list corruption after rename whiteout
 error

During a rename whiteout, if btrfs_whiteout_for_rename() returns an error
we can end up returning from btrfs_rename() with the log context object
still in the root's log context list - this happens if 'sync_log' was
set to true before we called btrfs_whiteout_for_rename() and it is
dangerous because we end up with a corrupt linked list (root->log_ctxs)
as the log context object was allocated on the stack.

After btrfs_rename() returns, any task that is running btrfs_sync_log()
concurrently can end up crashing because that linked list is traversed by
btrfs_sync_log() (through btrfs_remove_all_log_ctxs()). That results in
the same issue that commit e6c617102c7e4 ("Btrfs: fix log context list
corruption after rename exchange operation") fixed.

Fixes: d4682ba03ef618 ("Btrfs: sync log after logging new name")
CC: stable@vger.kernel.org # 4.19+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 27076ebadb36..d267eb5caa7b 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -9496,6 +9496,10 @@ static int btrfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 		ret = btrfs_sync_log(trans, BTRFS_I(old_inode)->root, &ctx);
 		if (ret)
 			commit_transaction = true;
+	} else if (sync_log) {
+		mutex_lock(&root->log_mutex);
+		list_del(&ctx.list);
+		mutex_unlock(&root->log_mutex);
 	}
 	if (commit_transaction) {
 		ret = btrfs_commit_transaction(trans);

Re: FAILED: patch "[PATCH] btrfs: fix log context list corruption after rename whiteout" failed to apply to 4.14-stable tree

[Sasha Levin]

On Mon, Mar 23, 2020 at 03:43:02PM +0100, gregkh@linuxfoundation.org wrote:
>
>The patch below does not apply to the 4.14-stable tree.
>If someone wants it applied there, or to any other stable or longterm
>tree, then please email the backport, including the original git commit
>id to <stable@vger.kernel.org>.
>
>thanks,
>
>greg k-h
>
>------------------ original commit in Linus's tree ------------------
>
>From 236ebc20d9afc5e9ff52f3cf3f365a91583aac10 Mon Sep 17 00:00:00 2001
>From: Filipe Manana <fdmanana@suse.com>
>Date: Tue, 10 Mar 2020 12:13:53 +0000
>Subject: [PATCH] btrfs: fix log context list corruption after rename whiteout
> error
>
>During a rename whiteout, if btrfs_whiteout_for_rename() returns an error
>we can end up returning from btrfs_rename() with the log context object
>still in the root's log context list - this happens if 'sync_log' was
>set to true before we called btrfs_whiteout_for_rename() and it is
>dangerous because we end up with a corrupt linked list (root->log_ctxs)
>as the log context object was allocated on the stack.
>
>After btrfs_rename() returns, any task that is running btrfs_sync_log()
>concurrently can end up crashing because that linked list is traversed by
>btrfs_sync_log() (through btrfs_remove_all_log_ctxs()). That results in
>the same issue that commit e6c617102c7e4 ("Btrfs: fix log context list
>corruption after rename exchange operation") fixed.
>
>Fixes: d4682ba03ef618 ("Btrfs: sync log after logging new name")
>CC: stable@vger.kernel.org # 4.19+
>Signed-off-by: Filipe Manana <fdmanana@suse.com>
>Signed-off-by: David Sterba <dsterba@suse.com>

Greg, I'm not sure why you tried this for 4.14 - it's tagged 4.19+ and
we don't have d4682ba03ef618 in 4.14 either.

-- 
Thanks,
Sasha

Re: FAILED: patch "[PATCH] btrfs: fix log context list corruption after rename whiteout" failed to apply to 4.14-stable tree

[Greg KH]

On Mon, Mar 23, 2020 at 12:44:58PM -0400, Sasha Levin wrote:
> On Mon, Mar 23, 2020 at 03:43:02PM +0100, gregkh@linuxfoundation.org wrote:
> > 
> > The patch below does not apply to the 4.14-stable tree.
> > If someone wants it applied there, or to any other stable or longterm
> > tree, then please email the backport, including the original git commit
> > id to <stable@vger.kernel.org>.
> > 
> > thanks,
> > 
> > greg k-h
> > 
> > ------------------ original commit in Linus's tree ------------------
> > 
> > > From 236ebc20d9afc5e9ff52f3cf3f365a91583aac10 Mon Sep 17 00:00:00 2001
> > From: Filipe Manana <fdmanana@suse.com>
> > Date: Tue, 10 Mar 2020 12:13:53 +0000
> > Subject: [PATCH] btrfs: fix log context list corruption after rename whiteout
> > error
> > 
> > During a rename whiteout, if btrfs_whiteout_for_rename() returns an error
> > we can end up returning from btrfs_rename() with the log context object
> > still in the root's log context list - this happens if 'sync_log' was
> > set to true before we called btrfs_whiteout_for_rename() and it is
> > dangerous because we end up with a corrupt linked list (root->log_ctxs)
> > as the log context object was allocated on the stack.
> > 
> > After btrfs_rename() returns, any task that is running btrfs_sync_log()
> > concurrently can end up crashing because that linked list is traversed by
> > btrfs_sync_log() (through btrfs_remove_all_log_ctxs()). That results in
> > the same issue that commit e6c617102c7e4 ("Btrfs: fix log context list
> > corruption after rename exchange operation") fixed.
> > 
> > Fixes: d4682ba03ef618 ("Btrfs: sync log after logging new name")
> > CC: stable@vger.kernel.org # 4.19+
> > Signed-off-by: Filipe Manana <fdmanana@suse.com>
> > Signed-off-by: David Sterba <dsterba@suse.com>
> 
> Greg, I'm not sure why you tried this for 4.14 - it's tagged 4.19+ and
> we don't have d4682ba03ef618 in 4.14 either.

Ah, I thought this was backported, as "simple" grep shows it showing up
in 4.14.110, but that was just a reference to the short git commit id.

I need to fix my scripts to always expand it to the full sha1 to prevent
that from catching.

thanks,

greg k-h