From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from zeniv.linux.org.uk (zeniv.linux.org.uk [62.89.141.173]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C83811FB3; Mon, 4 Aug 2025 03:23:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=62.89.141.173 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754277799; cv=none; b=edl+ONeseaRpS67c8Pjheo2RnnGVOTGh/HXOEdpFMVOn6wtq4qXOmOrKnA5CEz0aWYVoBVWCAHQDnO6Ls3hZCKmTGau8TlP/T0CKQEsm1XAGV7WaY5B09w3wokvAwuuJTkD7+bX5x1G/w2l99TK2vn8ijQmbuZIefwvpP5JYMv8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754277799; c=relaxed/simple; bh=rkHrsiltpyorC3JdIlb1s8D1l44/yq7sco9JKsORU8w=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=MzU1mEGRF/dGP/BH92wcsruSCohzqs8MLwAelHPaTlZQ44rTy1EYVSBzMF7ouVQpjD+WvsC2lr1KP7igbaAvyeblAXufho93i48NTJXXZJWzyPmEY/W7mO1gjj5ZK2tmb5H/NMNRraNI+e0ElOICHY7u0LbxSXXY/wiS0frO35w= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zeniv.linux.org.uk; spf=none smtp.mailfrom=ftp.linux.org.uk; dkim=pass (2048-bit key) header.d=linux.org.uk header.i=@linux.org.uk header.b=BnrkU7QJ; arc=none smtp.client-ip=62.89.141.173 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zeniv.linux.org.uk Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=ftp.linux.org.uk Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linux.org.uk header.i=@linux.org.uk header.b="BnrkU7QJ" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=linux.org.uk; s=zeniv-20220401; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=rkHrsiltpyorC3JdIlb1s8D1l44/yq7sco9JKsORU8w=; b=BnrkU7QJRevf9K0bcxD2TMqUgm LANvzmptr0416EUlmWmkx05xjNi2B9yAg9K+AFeFLQ/3I/SVx46NVd/CWVo/Yk3HNRvnPYVpVd4zW jDgdFwXHmqSW+DIHKQl+GHaHB/6IJvTDTpxoX2zr6giR0QI0KjTiAOy821Nkuy0R7Yp8D6LqM8P8d WXuUXfzeAKwAywDeWeBvU+G3bPR2RXjFQLPwBt4lCBtTQecb+8V8nwByjHUis/6b9GwDZmFpUtrqw yvtiEyYsVYOn/nOPol3Y0tSsWmwp2uI0C2HCzu+yEodmdL/ooPfq4iQBzbk5eMhkt+Vxc7+va+rsJ dVcC9rrQ==; Received: from viro by zeniv.linux.org.uk with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1uiln6-00000006nWu-12W2; Mon, 04 Aug 2025 03:23:12 +0000 Date: Mon, 4 Aug 2025 04:23:12 +0100 From: Al Viro To: Alan Huang Cc: syzbot , kent.overstreet@linux.dev, linux-bcachefs@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com, miklos@szeredi.hu, amir73il@gmail.com, linux-unionfs@vger.kernel.org Subject: Re: [syzbot] [bcachefs?] possible deadlock in bch2_symlink Message-ID: <20250804032312.GX222315@ZenIV> References: <67a72070.050a0220.3d72c.0022.GAE@google.com> <2F4A26BA-821F-4916-A8F6-71EDBA89A701@gmail.com> Precedence: bulk X-Mailing-List: linux-bcachefs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2F4A26BA-821F-4916-A8F6-71EDBA89A701@gmail.com> Sender: Al Viro On Mon, Aug 04, 2025 at 11:02:54AM +0800, Alan Huang wrote: > +cc overlayfs Sigh... 1) ovl_copy_up_workdir() should lock wdir with I_MUTEX_PARENT, same as filename_create(). 2) what the hell is bch2_symlink() need to lock the new inode for? page_symlink() doesn't need that; are there any bcachefs-specific reasons to bother with that?