From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from submarine.notk.org (submarine.notk.org [62.210.214.84]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 2222E3A1C9 for ; Wed, 11 Sep 2024 04:03:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=62.210.214.84 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726027385; cv=none; b=l567xmDHZKPbjSfQTYLj27X7GVgflTLFsDaiLmDsarTQKGb+yy9YlYOzN8JvqB6zHZmyDfCOfBQBWswMk5Cy65RYADNjI170BlKtpkNks1khLx1Q4xeMu2ob6uPxm9Mx8YAQGSrcSPcwVcvMcneK3miUBbgi0cznGKmCvQ7dcBk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726027385; c=relaxed/simple; bh=7jRIESI28vc2IwuINcmvQcRSKoOwYYNre2FNHnHRBb4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=jKJ+6qujWU4LNtqGrXswOgbmf6/fElihQ1QvkqebdlrMh+ajS6DnF7TOPId2PeqcZaMACjNkOYUqc8ig+dzIitW7oBlbzq7oBQcnYTD2ikVInS71meF2LSbEB86lsk2+qSBDXfdIFKE1dLk6QX2DBbr6De4+7qyIi4DTbs6oS8E= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=codewreck.org; spf=pass smtp.mailfrom=codewreck.org; dkim=pass (2048-bit key) header.d=codewreck.org header.i=@codewreck.org header.b=DDUXBgxh; arc=none smtp.client-ip=62.210.214.84 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=codewreck.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=codewreck.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=codewreck.org header.i=@codewreck.org header.b="DDUXBgxh" Received: from gaia.codewreck.org (localhost [127.0.0.1]) by submarine.notk.org (Postfix) with ESMTPS id 298C514C1E1; Wed, 11 Sep 2024 06:02:52 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=codewreck.org; s=2; t=1726027375; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=+7R/umzBoSPkJzUQofCvf7cDhPwvj1bDwUnnPr1rnd8=; b=DDUXBgxhcOrKNBwuEKAk1Ro/1pHlwg3BDnfFMQ4vgOPiKoqOZixd1Vi3V5OUZnA3+/6Hbx kjpTKI/TOhOzR7y7Vd4gyW/ghurbbnrjzP38CIQLrJUs/7ddSbx+kLc9KY0OMdz9FUQEzu bpBJ5E5lQwwyswhB2V+cdWOcAmu42AEFcHDAHyBKzPNnKhHLD3OQS+lkbErWw4jT87STze XbC/HPJIGpX8BDGzOHLIZ+hO28xa1I7x7SdCKFTSzcFNsPFPkgadkOb4J8Pe+t5EW5KQqE E1YY9q/khg6nq6X4Pom8yx7J8v1cAvDwuQNLKe49h15pIaBncDyMJ08laYxoIw== Received: from localhost (gaia.codewreck.org [local]) by gaia.codewreck.org (OpenSMTPD) with ESMTPA id ac6668da; Wed, 11 Sep 2024 04:02:51 +0000 (UTC) Date: Wed, 11 Sep 2024 13:02:36 +0900 From: Dominique Martinet To: David Sterba Cc: stable@vger.kernel.org, patches@lists.linux.dev, Greg Kroah-Hartman , Josef Bacik , Anand Jain , Sasha Levin Subject: Re: [PATCH 5.10 064/151] btrfs: change BUG_ON to assertion when checking for delayed_node root Message-ID: References: <20240901160814.090297276@linuxfoundation.org> <20240901160816.526197570@linuxfoundation.org> Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20240901160816.526197570@linuxfoundation.org> (this patch was already merged to stable last window, I was late on review -- this is more feedback for master that has the same code) Greg Kroah-Hartman wrote on Sun, Sep 01, 2024 at 06:17:04PM +0200: > From: David Sterba > > [ Upstream commit be73f4448b607e6b7ce41cd8ef2214fdf6e7986f ] > > The pointer to root is initialized in btrfs_init_delayed_node(), no need > to check for it again. Change the BUG_ON to assertion. > > Reviewed-by: Josef Bacik > Reviewed-by: Anand Jain > Signed-off-by: David Sterba > Signed-off-by: Sasha Levin > --- > fs/btrfs/delayed-inode.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/fs/btrfs/delayed-inode.c b/fs/btrfs/delayed-inode.c > index cdfc791b3c405..e2afaa70ae5e5 100644 > --- a/fs/btrfs/delayed-inode.c > +++ b/fs/btrfs/delayed-inode.c > @@ -986,7 +986,7 @@ static void btrfs_release_delayed_inode(struct btrfs_delayed_node *delayed_node) > > if (delayed_node && > test_bit(BTRFS_DELAYED_NODE_INODE_DIRTY, &delayed_node->flags)) { > - BUG_ON(!delayed_node->root); > + ASSERT(delayed_node->root); Note that if !delayed_node->root we will bug on a null deref immediately anyway. This patch was missing just one line of context, I've added it below: > clear_bit(BTRFS_DELAYED_NODE_INODE_DIRTY, &delayed_node->flags); > delayed_node->count--; > > delayed_root = delayed_node->root->fs_info->delayed_root; So, ASSERT doesn't feel appropriate -- if you want to protect non-developers from BUGs then the check needs to be spelled out and return early or not enter the if; or it really cannot happen (it used to be a BUG...) and the check can be removed altogether. -- Dominique Martinet | Asmadeus